ALBERT

Description: A review is presented of the shortcomings of most existing taper equations which predict diameter along the stem as a function of tree height and diameter at breast height. A new computerized system is developed that has many desirable features for tree profile prediction. This new system consists of two mathematical functions, one describing the upper bole and the other describing the lower bole. The two functions are linked together at the inflection point and are continuous at that point. Tests of this model on 32 species age and locality groupings of British Columbia species show that although there is still a slight bias near ground level, the prediction of diameter inside bark is almost perfect over most of the length of the trees.

Description: Damage caused by the white-spotted sawyer, Monochamusscutellatus (Say), to felled white spruce, Piceaglauca (Moench) Voss, in northern Alberta was studied to provide data for improving a damage assessment technique. Numbers, density, and size of larval entrance holes, length of larval galleries, and diameter of adult exit holes were examined on three 122-cm-long log sections cut near the butt, middle, and top of each of 30 trees. Information on larval development and survival and adult emergence was also obtained.Size of larval entrance and adult exit holes and gallery length decreased from the butt to top of the tree, numbers of entrance holes were similar at the three stem positions, and density of entrance holes increased from butt to top on both south and north aspects. The density of entrance holes around the logs showed two maxima, while the mean density was approximated slightly above midlevel on south and north aspects. Larval galleries extended to an average maximum depth of 7.5 cm into the wood. About 25% of adults emerged 1 year after oviposition, the rest emerged after 2 years. Mortality of M. scutellatus within the logs averaged 71%. The results are discussed in relation to sampling problems for damage assessment in felled and standing fire-killed trees.

Description: Some theory and observations are presented on the factors governing the start and spread of crown fire in conifer forests. Crown fires are classified in three ways according to the degree of dependence of the crown phase of the fire on the ground surface phase. The crown fuel is pictured as a layer of uniform bulk density and height above ground. Simple criteria are presented for the initiation of crown combustion and for the minimum rates of spread and heat transfer into the crown combustion zone at which the crown fire will spread. The theory is partially supported by some observations in four kinds of conifer forest.

Description: Oleoresin viscosity, flow (rate, duration, and total amount), and rate of crystallization were determined for Pinuselliottii Engelm., Pinuspalustris Mill., Pinustaeda L., and Pinusechinata Mill, in central Louisiana, U.S.A. Physical properties of the oleoresin and tree morphological characteristics (diameter at breast height, growth rate, height, crown ratio, and age) were not strongly related in either of the four species. Pinuselliottii oleoresin was extremenly viscous, crystallized very slowly, and flowed at a slow rate over a long period, and total yield was moderate. Pinuspalustris oleoresin was of moderately high viscosity and very high yield and had a high rate of flow. Pinustaeda and Pinusechinata oleoresin had, on the average, low viscosity, a moderate to low total yield, a short duration of flow, and rapid rate of crystallization. A discriminant function analysis revealed that 19% of the Pinustaeda and 6% of the Pinusechinata trees had oleoresin properties more similar to Pinuspalustris and Pinuselliottii than to the means for their own species. This information is being used to assess tree susceptibility to attack by Dendroctonusfrontalis Zimm.

Description: Previous studies of budworm impact on balsam fir stands have correlated the probability of tree damage and mortality with only a few broad stand characteristics. Improved predictability may be obtainable from a model incorporating foliage production of fir, budworm feeding rate, and tree vulnerability. Some data are presented on the first two variables with comments on further research requirement.

Description: An index was developed that takes into account the combined influence of air and soil temperatures, light, and the availability of soil moisture upon photosynthesis by a unit area of fully exposed foliage of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). The index is derived from a summation of daily estimates of carbon assimilation (milligrams CO2 assimilation per decimeter per day) for an entire year. In a comparison of forest environments in western Oregon the index was correlated to a measure of forest productivity (r2 = 0.99). Furthermore, it suggests that much of the annual carbon fixation occurs during the mild winters characteristic of the region. The ability to assess the effects of frost, soil drought, and other variables separately was valuable in explaining differences between coastal, valley, and mountainous sites.

Description: Distribution of N, P, K, Ca, and Mg in the tree, understory, forest floor, and mineral soil horizons was determined for two series of postfire forest stands in northeastern New Brunswick. Twelve pure jack pine stands (Pinusbanksiana Lamb.) and 11 mixed hardwood stands aged 7–57 years were examined. Regression equations relating aboveground tree nutrient content to diameter for eight tree species were calculated. The jack pine stands demonstrated variable stand density, but adjustment to normal stocking produced a sigmoid nutrient accumulation pattern in the tree layer during the 60-year period. Nutrient accumulation in the tree layer of both series of stands closely approximated biomass accumulation. Understory nutrients formed a significant fraction of the total aboveground pool, particularly in the younger stands. Organic and mineral soil horizon nutrients were found to be highly variable for both series of stands; this was postulated to be a result of the fire origin of the stands, with varying fire intensity and postfire conditions resulting in different nutrient losses from the site.

Description: Twenty-three sugar maple trees, Acersaccharum Marsh., that had been defoliated by hand for 3 consecutive years (1971, 1972, and 1973) and nine undefoliated trees were wounded with a drill bit in March 1974. After two full growing seasons, wound areas on defoliated trees were larger than those on undefoliated trees because more bark tissue died originally around the wounds on defoliated trees, and because there was less wound closure resulting from poorer radial growth. There was no significant increase in internal discoloration, but decay was found in two defoliated trees. In undefoliated trees, wound area was highly correlated with annual growth increment and resistance to pulsed electric current. In defoliated trees, wound area was highly correlated with starch content of the roots; trees with lower starch content had larger wounds.

Description: The beta, Johnson's SB, Weibull, lognormal, gamma, and normal distributions are discussed in terms of their flexibility in the skewness squared (β1) − kurtosis (β2) plane. The SB and the beta are clearly the most flexible distributions since they represent surfaces in the plane, whereas the Weibull, lognormal, and gamma are represented by lines, and the normal is represented by a single point.The six distributions are fit to 21 data sets for which both diameters and heights are available. The log likelihood criterion is used to rank the six distributions in regard to their fit to each data set. Overall, Johnson's SB distribution gave the best performance in terms of quality of fit to the variety of sample distributions.

Description: Peatland types were compared to reveal differences in growth of dominant and codominant trees from undrained and artificially drained sites. The comparisons, based on tree height attained at the age of 100 years, indicate that growth improves by about 6 m in bog types and by about 4 m in fen–marsh types. To allow identification of similar sites in different localities and prediction of growth potential of sites not directly under study, 15 peatland types were assigned to five trophic groups on the basis of macronutrient content of the peat, using an automatic clustering method. The nutrient elements considered are known to influence growth on peatlands. The paper gives an account of site conditions. sampling technique, methods of comparison, and clustering. Detailed results are presented and explained.

Description: Deep plowing was evaluated in the field and simulated in a greenhouse study in an attempt to isolate soil factors responsible for yield effects on a Duagh Solonetz soil. Generally, fertilization provided a more significant yield response than deep plowing in the field or horizon mixing in the greenhouse. In the field, however, deep plowing in combination with fertilization produced an additional 542 kg/ha of alfalfa-bromegrass forage over fertilization alone [Formula: see text]. Also, in fertilized greenhouse treatments, retaining the A horizon on the surface while mixing sub-horizons proved significantly beneficial over mixing all three horizons [Formula: see text]. The main factor responsible for yield effects appeared to be the Ca enrichment of surface and B horizon areas. An increase in the Ca:Na ratio improved water intake rates and reduced water-logging of the soil, thereby providing a more suitable medium for root development and a more efficient use of indigenous and applied N.

Description: More than 50 soil profiles have been examined and analyzed in the Schefferville area, and 5 are studied in detail. Leaching, sesquioxide translocation and surficial organic matter accumulation are the main pedogenic processes. The soils are acid, and leaching is generally confined to a depth of 60 cm. Morphological evidence of podzolization occurs in well drained soils, and analytical data reveal the translocation of Fe, Al and organic matter in the profile. Organic soils develop at sites which are permanently waterlogged and morphological and chemical evidence of gleying occurs in soils that are waterlogged for most of the summer. In soils that are waterlogged for only part of the summer, there is morphological and chemical evidence of podzolization and gleying, as shown by translocation of Fe, Al, Mn and organic matter and by mottling. Because of the reddish-brown parent materials, morphological evidence of soil development is weaker than in soils developed from deposits on the Canadian Shield. Clay mineral transformations are pronounced, with the decomposition of chlorite, kaolinite and mica and the formation of smectite in Ae horizons.

Description: not available

Description: The accumulation of dry matter and N in wheat (T. aestivum L. cv. Manitou) grown on stubble land in lysimeters at two moisture levels and seven rates of N was measured and related to moisture use at five stages of development. In the irrigated lysimeters, leaf areas, plant dry matter and N content increased with fertilizer N. In the dry lysimeters, low rainfall between the shot blade and anthesis stages produced moisture stress; consequently, dry matter production and leaf area were depressed and plants lost significant amounts of N at rates of N 〉 61.5 kg/ha. Rain in the latter part of the growing season permitted the plants to recover and by maturity plant dry matter and N content increased with N. Approximately twice as much plant dry matter was produced in the wet treatment as in the dry for all levels of N. Total evapotranspiration (ET) increased with applied N in the wet treatment, and was much higher than in the dry treatment. It was not affected by applied N in the dry lysimeters. Root weight increased exponentially up to the shot blade stage. Between anthesis and maturity, it decreased in the top 75 cm in the dry and top 30 cm in the irrigated soil profile, while in the deeper segments it remained constant. Root weight increased curvilinearly with increasing N under irrigation. On dryland, rates of N 〉 41 kg/ha depressed root growth at the shot blade stage and at anthesis. Average root yields under wet conditions were 220, 1,920 and 1,425 kg/ha at 3-leaf, anthesis, and maturity, respectively; under dry conditions they were 220, 1,535 and 875 kg/ha. The root weight constituted 76% of the total plant weight at the 3-leaf stage and 15.6% at maturity. The average root N content at maturity made up 9.4–11.5% of the mean plant N. Root density decreased curvilinearly with depth. At the 3-leaf stage about 62 and 23% of the root system was located in the top 15- and the 15- to 30-cm segments of the profile, respectively; at maturity these proportions were 46 and 15%. N did not influence root distribution but irrigation increased root growth in the top 15 cm of the profile by about 5%. Rate of moisture use was directly proportional to rate of root growth.

Description: The accumulation of aboveground dry matter (DM) and nitrogen (N) by spring wheat (T. aestivum L. cv. Manitou) grown on stubble land in lysimeters at two moisture levels (irrigation and natural rainfall) and seven rates of N was measured at five sampling dates. With irrigation, DM increased exponentially with time and N fertilization. This also occurred on dryland except between shot blade and anthesis when DM accumulated more slowly and plants lost 20% of their N at application rates 〉 61.5 kg N/ha. Rainfall after anthesis increased grain yields of dryland crops fertilized with 〉 61.5 kg N/ha more than those receiving less N because the former plants still had residual fertilizer N available to them. Grain yield response to N fertility followed the law of diminishing returns on irrigated land, but on dryland the relationship fitted a logarithmic growth curve. Grain yield when neither water nor N was added was 1,600 kg/ha; it increased by 71, 47 and 300% when water, 164 kg N/ha, and water plus 164 kg N/ha, respectively, were applied. On dryland, grain protein was 15.4% with no N applied and 17.0% at rates 〉 61.5 kg/ha; on irrigation, it increased from 14.1 to 15.7% with increasing N levels. Number of heads and kernels and kernel weight were increased by irrigation but only the two former parameters were increased by N. Dry matter accumulation was related to N concentration in plants by: DM = (%N)−k where k was

Description: In a field experiment with different crops on a loam and a sandy loam soil in a 3-yr period, N uptake by grasses accounted for 64–96% of the N fertilizer added at a rate of 112 kg N/ha annually. The recovery was 40–54% when the rate was 448 kg N/ha. The grass species were more effective than corn in removing N from the soils. Regardless of the rate of fertilizer used, however, the amounts of NO3-N in the soil of corn, fallow and grass plots sampled to a depth of at least 90 cm in the fall were high enough in many instances to account for much of the excess of added N not used by the crop. Corresponding data for NO3-N in the soils in the following spring showed that except for the moderately fertilized grass plots, the fertilized soils were susceptible to considerable loss of excess NO3-N from early fall to the following spring. In several instances, the data indicated a movement of NO3-N, since the amounts were reduced in the upper soil layers and increased in the lower ones during the fall–spring period.

Description: Forms of nitrogen in 92 samples were measured in a study designed to determine the similarities and differences in the nitrogen distribution in various horizons of a wide range of Canadian soils. The samples, representing all of the nine soil orders, were chosen from different climate and vegetation zones. Some peat soils were analyzed also. The data were first grouped according to the nitrogen content of the samples, but the amino acid composition of the soil "protein" did not appear to be related to this. The data were then grouped according to LFH, A, B and C horizons and also according to the Ah, Ap, Ae, Bhf, Bh, Bm and Bt layers. Again, few significant differences in the amino acid composition could be found. Data for the average amino acid composition and standard deviations for 92 mineral soils, 6 LFH and 2 ’O’ horizons of these and 18 peat soils were calculated. Since the analytical and sampling errors appear to be relatively small and would not account for all the variation between samples, there appeared to be real but relatively small and random differences in the amino acid composition of the different samples. The data for the individual soils supported this conclusion; for instance, some samples had very small or barely detectable amounts of hydroxyproline, while with other soils it made up 1–2% of the amino acid nitrogen. The amino sugar composition was more variable and the glucosamine/galactosamine ratio varied from 2:1 for the LFH horizons to 1:1 for the peat soils. In general, however, the soil "protein", which is probably largely the result of microbial degradation and synthesis, is remarkably similar to its amino acid composition. Amino acid nitrogen made up over half of the total nitrogen of the LFH and O horizons. This underestimated the "protein" nitrogen, since there is probably some amide nitrogen (about 5%) not included. In the mineral soils probably about 40% was "protein" nitrogen (including aminde), 5% was amino sugar nitrogen, 18% hydrolyzable unidentified nitrogen and 13.5% was insoluble in the acid used for hydrolysis. Clay-fixed ammonium made up 17% of the total nitrogen and much of the hydrolyzable ammonium came from this.

Description: Rates of hydrolysis of water-soluble sodium pyrophosphate and sodium tripolyphosphate, applied to soil at 200 ppm P, were extremely rapid (about 2–7%/h) during the 0 to 24- or 0- to 48-h period following phosphate application but decreased with time of incubation. Rates of hydrolysis increased linearly and increased about two- to threefold as temperatures were increased from 5 to 35 C or from 5 to 50 C. Inconsistent results were obtained at temperatures above 50 C. Increases in incubation temperature increased the total amount of added polyphosphate hydrolyzed by the soil in 120 h from about 40 to 70% at 5 C to about 80 to 95% at 35 C and 50 C. Water-soluble polyphosphate hydrolyzed at a greater rate than 0.5 N H2SO4-soluble polyphosphate. However, the effects of temperature on rate of hydrolysis of acid-soluble polyphosphate and water-soluble polyphosphate were similar. Polyphosphate hydrolyzed at a greater rate in the noncalcareous Newdale soil than in the calcareous Lakeland soil. Rate of tripolyphosphate hydrolysis was usually greater than rate of pyrophosphate hydrolysis. Rate of hydrolysis of water-soluble polyphosphate, expressed as %/h, decreased exponentially as concentration of applied polyphosphate increased from 200 to 1,600 ppm. However, rate of orthophosphate production per unit time increased exponentially with increased substrate concentration.

Description: After 8 mo of decomposition, under laboratory conditions, the unlimed surface sample (0–15 cm, pH 3.8) of an acid peat bog contained about five times as many microbes as the unlimed subsurface material (15–41 cm, pH 4.1). As measured by CO2-C released and numbers of bacteria and actinomycetes, lime had greater effects on the microbial activity of the surface material. Nitrifying bacteria were present and needed lime to become active. Fungal numbers decreased with lime and only 12 genera were found. Temperature had little effect, whereas pH had a marked effect on the distribution of fungal genera. Fusarium oxysporum, Cephalosporium acremonium and a frequently isolated nematode-destroying fungus Harposporium lilliputianum were found only at pH 7.5 and thus appeared to be alien fungi that responded well to an environment of high pH and cultivation. Before incubation, the unlimed lower sample was higher in carbon, nitrogen and methoxyl but lower in hexose, pentose and uronic acid than the unlimed upper sample. During decomposition there was a tendency for hexose and pentose to decrease, this being more noticeable in the upper material. No appreciable changes in nitrogen, carbon, methoxyl and uronic acid content occurred in either sample. Dry matter lost in the surface ranged from 8 to 13% while in the lower material it was from 2.0 to 3.5%. Despite sufficient NPK and a substantial sugar content, Sphagnum litter decomposes at a slower rate than some tree leaf litters. From the literature it is speculated that the slowness is due to the presence of microbial-inhibiting substances such as phenolic compounds.

Description: Radiocarbon dating was used to determine the mean residence time of the organic matter from a Gleysolic Ap horizon of eastern Canada. The total soil organic matter and the fulvic acids dated modern, the humic acids as 1,220 ± 150 yr B.P. and the humin as 180 ± 100 yr B.P. Acid hydrolysis of the total soil organic matter yielded a soluble fraction dating modern and an unhydrolyzed material dating 1,530 ± 110 yr B.P. Acid hydrolysis of this topsoil appears practical to separate the soil organic matter into two fractions of different stability. Fractionation into fulvic, humic acids and humin may help to give information on the dynamics of the soil organic matter by separating the soil into at least three fractions of varying stability.

Description: Urea was added as a band in the middle of 12-cm-long columns of Wellwood clay loam (pH 6.6) and the soil was incubated at constant uniform temperatures of 10, 15 and 20 C. A similar set of the soil samples was incubated in columns which had a temperature of 23 C at one end and 8.5 C at the other end. At uniform temperatures the rate of disappearance of ammonium and the formation of nitrate from the banded urea was found to increase with increasing temperature. Nitrite was found to accumulate during the incubation period but disappeared with the prolonged incubation at 15 and 20 C. At 10 C incubation, the maximum nitrite accumulation occurred at 12 wk, the longest incubation time used. Various ionic species, NH4+, NO2− and NO3− were found to be nearly symmetrically distributed from the point of placement. When the soil was incubated under a temperature gradient, NO3− and to a lesser degree NH4+ accumulated near the end of the column.

Description: Soil samples collected from the Breton plots, which had received various treatments and had been cropped to a 5-yr rotation of cereals and forages over a 40-yr period, were analyzed to determine the effects of the treatments on soil acidity. Treatments included applications of fertilizers at low rates, infrequent applications of lime, applications of manure and applications of various combinations of these. Those receiving NS, NPS and NPKS were more acidic than the check plots and those receiving lime, lime + NPKS and P as 0–45–0 were less acidic. Plots treated with manure or manure + NPKS were not acidified. Since 1967, a brome–alfalfa mixture has been seeded and on the more acidic plots the established stand contained less than 30% alfalfa as compared to greater than 70% in the lime or P (0–45–0) treatments. Liming one half of each plot in each series in 1972 significantly increased the stand and reduced the aluminum content of alfalfa, especially in the more acidic plots. Alfalfa grown on these more acidic plots had, in general, higher Mn and Al and lower N contents than did alfalfa in the limed portions of the plots. The poor growth of alfalfa on plots receiving NS, NPS and NPKS is attributed to the acidifying effects of the fertilizers being sufficient to inhibit nitrogen fixation and induce some toxic concentrations of Al and Mn in the soil.

Description: The effects of dispersion and sieving on the determination of fiber content was studied using four peat materials selected for their range of properties. In addition, a method of particle-size analysis of peat materials and chemical characterization data of the particular-size fraction are presented. Controlling the sieving operation effected a reduction in the coefficient of variation of the fiber content data to 2.7% as compared with 26.7% for the conventional rubbed fiber method. The somewhat more effective dispersion of the peat in 0.025 M pyrophosphate than in water did not compensate for the associated disadvantage of increased ash content of the pyrophosphate-treated samples. Thus, the recommended procedure involves dispersion of peat in water for 16 h. The proportion of the 100-mesh (0.15-mm) fraction reflected both the stage of decomposition and the botanical origin of the peat materials. Thus, particle-size fraction would be useful in the characterization of peat materials. Cation exchange capacity and content of both Fe and P varied inversely with particle size.

Description: Slow release N fertilizers were considered as efficient sources of N for fall application to corn (Zea mays L.). Accordingly, sulfur-coated urea (SCU) and crotonylidene di-urea (CDU) were compared with urea in several field experiments. Neither SCU nor CDU were shown to be advantageous over urea in terms of grain yield. Similarly, the N content of the leaf opposite and below the ear did not show a greater availability of N from SCU and CDU than from urea applied in the fall. Response to residual N from previous applications of urea, SCU, and CDU was obtained for 2 yr after application. There was a tendency for a greater response to residual SCU. The concentration of NO−3 in the 0- to 18- and 18- to 36-cm soil layers was usually less with slow release N fertilizers than urea at early May sampling times. By mid-June, the NO−3 concentration had increased substantially with both urea and the slow release N fertilizers. In 2 yr when urea was also applied in the spring, the NO−3 concentration with spring-applied urea was higher than with fall-applied urea. This reflects the greater loss of N during the winter months with fall-applied urea. After growth terminated in the fall, NO−3 apparently continued to be released from urea and slow release N fertilizers at similar rates. Thus slow release N fertilizers also have potential to contribute significantly to the NO−3 concentration in drainage and groundwaters. In general, there was no noteworthy difference between SCU and CDU in this study. Also, slow release N fertilizers did not show any agronomic advantage over urea when applied in the fall.

Description: Monthly sampling of stem inner bark, roots, litter, humus, and mineral soil was carried out in six 0.1-ha plots in a 47-year-old Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) stand for 1 year. Pairs of plots had received urea fertilization at the rates of 0, 224, and 448 kg nitrogen (N)/ha 4 years previously. Inner bark and roots were chemically analysed to determine concentrations of total N, soluble N, ninhydrin-positive compounds, monosubstituted guanidino amino compounds, arginine, and proline. Concentration of total N was determined in litter, humus, and mineral soil samples, and concentration of mineralizable N was also determined in humus and mineral soil.All sets of data showed an effect of season, but analysis of root soluble N, root guanidino compounds, root arginine, and litter total N were the most satisfactory for distinguishing differences in N level due to fertilizer treatments. For this purpose root sampling was best done in June and July, and litter sampling between January and May. Soluble N concentration was higher in inner bark than in roots, but arginine concentration was higher in roots than in inner bark. Root arginine concentration was high in winter and decreased to a low level in October before starting to accumulate again, suggesting it behaves as a N storage compound. Litter total N showed a decrease in concentration in July and August, followed by a recovery.

Description: Financial maturity rotation of stands is a new concept in the province of Quebec; it has been recently applied to some softwood and hardwood stands. In Quebec the Lands and Forest department has used the maximum of the mean annual physical growth, which does not include economic variables, to determine the optimum length of the rotation. The estimation of optimum financial length precisely considers factors such as prices, operating and management costs, and capital opportunity cost which the manager ought to use for his investment decision. In forestry, as in all other economic activities, financial maturity is a useful and important tool for determining the maximum feasibility of the present investment project.

Description: Gibberellin A3 (GA3) induced prolific pollen cones and seed cones in 1- and 3-year-old yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) trees. In the first experiment, the GA3-induced cones developed normally and the viable pollen was allowed to pollinate the GA3-induced seed cones. Embryo development was normal and mature seeds were produced, of which 55% were filled and 93% of all filled seed germinated. In a second experiment 1-year-old potted seedlings grown in cold frames were treated with GA3 in June and July under natural long days (about 18 h of light) or short days (8 h of light). Under the long days, 4 and 5 weeks of GA3 treatment produced the maximum number of pollen cones and seed cones, respectively. Treatment with GA3 under short days induced fewer cones and gave inconsistent results.Thus, induction of cones in yellow cypress by a foliar spray can be accomplished easily and economically in seedlings or in young trees in a seed orchard under natural long days. When compared with cones which develop under natural conditions, GA3-induced cones produced a higher percentage of filled seed with a high germination percentage.

Description: As part of a 2-year study of the effect of thinning on evapotranspiration in Douglas fir (Pseudotsugamenziesii (Mirb.) Franco), the relationship between stomatal diffusion resistance (rs) and environmental variables were studied. Research was conducted in an unthinned stand (1840 stems ha−1) with negligible undergrowth and a thinned stand (840 stems ha−1) with substantial salal (Gaultheriashallon Pursh) undergrowth. During the daytime rs was mainly related to the soil water potential (ψs) and the vapour pressure deficit (v.p.d.) of the canopy air. Daytime values of rs for Douglas fir ranged from 2 to 60 s cm−1 for values of v.p.d. between 4 and 24 mb (4 and 24 × 102 Pa) and values of ψs between 0 and −12.5 bars (0 and −12.5 × 105 Pa). Although increasing rs was usually associated with decreasing pressure potential of the twig xylem (ψt), increasing rs appeared to be associated with increasing ψt when the v.p.d. was high. Stress history was found to cause a shift in the relationship of rs to ψt, but had little effect on the relationship of rs to v.p.d. and ψs. Daytime values of rs for salal ranged from 2 to 45 s cm−1. This stomatal behaviour suggests that as the soil dried out, salal transpiration accounted for an increasing fraction of the total water loss by the thinned stand.

Description: Gross precipitation and throughfall in the open and under forest vegetation were sampled and analyzed for total content of N, P, K, Ca, and Mg. The results indicate the importance of the tree canopy, Pinusresinosa Ait. and Betulapapyrifera Marsh., in modifying the nutrient content of precipitation passing through the overstory vegetation. Contributions of nutrients to throughfall by the understory vegetation, mainly Coryluscornuta Marsh., were related to the areal coverage of the hazel as well as to high levels of nutrients in the hazel foliage. Gross precipitation annually added relatively small amounts of major nutrients to forest ecosystems in northern Minnesota.

Description: In 1966, numbers of seeds of dwarf mistletoe (Arceuthobiumamericanum Nutt. ex Engelm.) dispersed from two transplanted lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) decreased logarithmically with increasing distance from the trees. In two study areas in 1967–1969. dispersal of seeds from individual plants began in late August and was completed in 2–3 weeks. Differences of up to 2 weeks in the beginning and duration of dispersal were apparent between the areas. On one occasion, a difference in seed dispersal was noted between plants originating from seed collected at the two study areas and growing on a single tree at another location. Seed germination began in middle to late April, and in 4–6 weeks, 10–50% of the seeds had germinated.

Description: Xylem pressure potential was measured in black spruce in interior Alaska to determine the patterns of water stress under conditions of permafrost and long photoperiods. The general shape of the daily stress curve was similar to that reported for other species at lower latitudes. The primary effect of long photoperiods was to shift the times of stress maximums and decreases. Trees on sites with maximum annual thaw depths of 26 and 100 cm equilibrated daily with maximum predawn stress values of about −5 bars (1 bar = 100 kPa). Minimum stress during the day was generally −10 to −16 bars and did not exceed −18 bars for the entire growing season. An abundant water supply in the rooting zone derived from ice in the thawing soil was probably the contributing factor which prevented large seasonal changes in the daily pattern of moisture stress.

Description: A pattern of alternate-year production of strobilus buds and latent lateral buds occurred on bearing shoots in the reproductive zones of the crowns of balsam fir (Abiesbalsamea (L.) Mill.) trees. The timing of all growth events on such shoots and the relative sizes and numbers of organs produced provided a reasonable physiological (source–sink) basis for the biennial production of strobili in this species.

Description: A model fitted to cross-sectional observations is proposed which links the growth of consumption of structural wood materials and paper and paperboard to the economic and demographic growth of developed and developing economies. It was found that the response of consumption per capita to a specific growth of income per capita decreases systematically as the level of consumption attained increases. The consumption functions, for both groups of products, differed significantly for high-income and low-income countries. A set of input-output relationships was also established to estimate the amounts of wood pulp and industrial roundwood required to produce specific amounts of structural and paper materials. Those relationships have significantly shifted during the period 1961–1971, indicating an improvement in the efficiency of raw-material usage by the wood-products industries. The full model was applied to calculate the levels of consumption and of raw-material requirements consistent with Timbergen's indicative world plan (Timbergen, J. 1976. Development and environment aims: an intuitive view. In World modeling: a dialogue. Editedby C. W. Churchman and R. O. Mason. North Holland, Amsterdam, pp. 55–61). Given Timbergen's targets for world economic and demographic growth, a considerable improvement would occur in the balance of consumption between developed and developing countries but consumption per capita of industrial roundwood equivalent would still be three times higher in developed countries by the year 2010. The main growth of industrial roundwood consumption would occur in the paper and paperboard industry which would consume 65% of the world output by the end of the period. Developing countries would by that time become the main market for paper and paperboard products.

Description: Dwarf mistletoe (Arceuthobiumamericanum Nutt. ex. Engelm.) infected by the fungus Colletotrichumgloeosporioides Penz. sensu von Arx was examined in two areas of young lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) in southwestern Alberta. The fungus infected 35% and 75% of the dwarf mistletoe plants, 6% and 54% of the aerial shoots, and 7% and 8% of the berries in the respective areas. The number of dwarf mistletoe berries and maximum shoot lengths of dwarf mistletoe plants were significantly reduced by the fungus, and dead plants were more frequent than in areas where the fungus was absent. However, numbers of new dwarf mistletoe plants were not significantly reduced by the fungus. Evidently future increase in numbers of dwarf mistletoe plants and eventual damage to young lodgepole pine in the areas will not be significantly decreased by the fungus.

Description: Environmental factors of bud morphogenesis in young spruce seedlings were investigated by inducing bud set, subjecting the plants to various treatments during bud formation, then counting the numbers of needle primordia formed when bud morphogenesis was complete. Ambient temperatures greatly influenced needle initiation; the optimum was at least 25 °C, and initiation was much slower at 20 and 15 °C. By contrast, light intensities between 3350 and 22 000 lx had little effect. There was no response to photoperiod between 6 and 15 h, but initiation was markedly reduced at less than 6 h. Responses to soil moisture potential were also weak, in the range of 0 to −900 kPa, although a delay in attainment of experimental treatment may have obscured a stronger influence. Bud morphogenesis retarded by unfavourable environmental conditions ceased at the same time as (or earlier than) morphogenesis under favourable conditions. The practical implications of a definite morphogenetic interval are discussed.

Description: A model was described which simulated xylem pressure potential and leaf surface resistance for a white oak (Quercusalba L.) tree and several saplings in central Missouri. The simulation was accomplished using a deterministic approach and was applicable from after leaf maturation in the spring to leaf senescence in the fall. Soil moisture content, vapor pressure deficit, and solar radiation were the required driving variables. The Ohm's law analogy describing water potentials and fluxes in the soil–plant–atmospheric continuum served as the basis for the model. The model was tested with data not used in the original parameter estimation, and very close agreement between observed and predicted values was found. The patterns of xylem pressure potential and leaf surface resistance obtained from simulation runs imply that white oak has a significant amount of stress tolerance and an ability to avoid severe dehydration.

Description: The growth of the share of particle board production (measured as a fraction of total wood-based panels) has been analyzed using data from 25 industrialized countries. The trends in each country during the period 1955–1973 were represented by logistic models, analysis of which suggested the following conclusions. The particle board share of panel production was expected to reach a long-term maximum which could be estimated for most industrialized countries; this maximum varied widely from country to country. In most countries, except for Canada, Finland, Sweden, and the United States, the particle board share seemed close to having reached its long-term maximum in 1973. Countries in which the particle board share grew more initially slowly tended to be those in which the long-term maximum share was higher. The long-term maximum share of particle board was significantly lower in eastern European countries than in market economies. Using information from the other 21 countries allowed inferences regarding the long-term growth of particle board in Canada, Finland, Sweden, and the United States where particle board is still a small part of total panel production. Increasing distance from the Democratic Republic of Germany, which initiated particle board production, and the availability of a large supply of roundwood have generally delayed the time of adoption of particle board. Other things being equal, the growth rates of the particle board share of total panel production appeared to be higher in countries with high economic growth and lower in countries with high wood availability.

Description: Conelet abortion in longleaf pine (Pinuspalustris L.) ranged from 85 to 100% in 4 of 5 years in a clonal seed orchard in southeastern North Carolina. Investigation of the cause of the malady was inconclusive, but freeze damage, seed bugs, and inadequate pollen supply were excluded as principal causes. Where combinations of balanced fertilizers and ammonium nitrate had been used in the orchard, abortion was variable by clone, with some clones showing more abortion under higher fertilizer regimes.

Description: From an analysis of fire records in New Brunswick for the period of 1920–1975, the fire history and rotation patterns are presented. Mean and median annual burns have been 12 000 ha (0.15% of the province) and 2500 ha (0.03% of the province), respectively, but the fire rotations have been widely different for different vegetation types. The most extensively burned vegetation type of red spruce – hemlock – pine has had a fire rotation period of 230 years. Hardwood and high-elevation conifer vegetation types have had fire rotation periods of over 1000 years.

Description: Starch gel electrophoresis was used to survey for genetically determined enzyme mobility differences among 297 megagametophytes of red pine (Pinusresinosa Ait.) from five widely separated geographical sources. Consistent and reproducible enzyme banding patterns were observed with five of the seven isozyme systems assayed. No variation in band mobility was observed in any of these systems. This result stands in contrast with those reported from surveys of allozyme variation in other coniferous species but is consistent with the low degree of genetic variation observed in red pine for higher levels of genetic organization. It is concluded that red pine is genetically depauperate.Possible explanations for restricted genetic diversity are discussed. The most plausible explanation suggests that red pine was at sometime, possibly during the Pleistocene, reduced to a small refugial population and has yet to reestablish equilibrium heterozygosity.

Description: Small black cherry (Prunusserotina Ehrh.) seedlings grow slowly and soon die in low-density cherry–maple (Acerrubrum L.) orchard stands colonized by a dense ground cover of bracken fern (Pteridiumaquilinum L.), wild oat grass (Danthoniacompressa Aust.), goldenrod (Solidagorugosa Ait.), and flat-topped aster (Asterumbellatus Mill.). Studies of orchard stand persistence indicated that allelopathic interference occurred between black cherry seedlings and the herbaceous ground-cover plants. Foliage extracts of fern, goldenrod, and aster inhibited seed germination; aster foliage extract inhibited both shoot and root growth of seedlings growing on cotyledonary reserves; foliage extracts of fern, grass, goldenrod, and aster and root washings of goldenrod and aster inhibited shoot growth and dry weight accumulation of seedlings that had exhausted cotyledonary reserves. Soil from the upper horizons of an orchard stand did not moderate the toxicity of the herbaceous foliage extracts or root washings.

Description: The literature on endogenous gibberellins (GAs) of conifers, and on processes correlated with changes in GA-like substances, or processes affected by exogenous application of GAs is reviewed. It is now apparent that GAs mediate or influence many different growth and development processes in conifers, although just how they evoke the observed responses remains obscure.Practically, the use of certain GAs on conifers should allow advances to be made in the areas of tree breeding (i.e. the promotion of early flowering) and enhancement and regularization of seed production. The possible use of GAs to enhance early vegetative growth is feasible for many species. The use of endogenous GA levels, rate of synthesis, or metabolism as screening techniques in progeny testing, while still speculative, appears attractive.

Description: Methods have been developed to yield total tree estimates of biomass for various components of a tree (trunk, axes, twigs, and needles) and its community of epiphytes (microorganisms, lichens, and bryophytes). Trees were sampled with the help of climbing techniques modified from mountain climbing. Two stages of sampling were involved. First, all units of the population were described so that their weights could be predicted. Second, several units were chosen with probability of selection dependent upon predicted weight and sampled in detail. Biomass estimates from the sampled units were expanded to tree totals with information gathered during the first sampling stage. Internal structure of the crown (tree components and epiphytes) is illustrated by maps of trunk and branch systems and by diagrams of horizontal and vertical distributions. This internal structure was also derived from the first sampling stage.These methods have been applied to nine old-growth Douglas fir trees (Pseudotsugamenziesii (Mirb.) Franco). Data from a single 400-year-old tree (1.46 m dbh, 77 m in height) in the H. J. Andrews Experimental Forest in the western Cascade Mountains of Oregon are presented. Biomass and surface area estimates are as follows: trunk, 26 870 kg, 223 m2; axes (〉4 cm), 1530 kg, 81 m2; living twigs (

Description: not available

Description: Intraprovenance variation in the rate of photosynthetic CO2 exchange was determined for 20 half-sib families of pitch pine. During early seedling development, rates of CO2 uptake were comparable with those for highly productive crop plants and the highest yet reported for conifers. Differences among families were small but statistically significant. Genotype-environment interactions were relatively unimportant, i.e., patterns of photosynthetic response to temperature and light were the same for all families within the limits of error.

Description: Growth responses of a young, naturally regenerated Abiesbalsamea stand managed for Christmas trees in Nova Scotia were measured over the 2 years after application of dolomitic limestone and factorial combinations of four levels of N, two levels of P, and two levels of K. In the first season, nitrogen-treated trees were darker green and had heavier terminal buds. Other significant responses owing to nitrogen were greater numbers of apical and lateral buds in the second season and greater length of leaders, lateral shoots, and needles in both seasons. The only significant main effect of P was on bud development. Neither K nor lime had any significant influence, and no significant interactions among any nutrients were detected. Growth responses did not differ significantly among three rates of N application over the 2-year period indicating.that for short-term cultural purposes the higher rates are inefficient on this site.

Description: This study was designed to estimate the degree of genetic control of the response to sulfur dioxide (SO2) and ozone (O3), alone and in combination, in trembling aspen (Populustremuloides Michx.). Rooted cuttings from 11 randomly selected trees in central Wisconsin were used in the study. Significant interclonal variation was found in the response of the 11 clones to 3-h exposures to 0.50 ppm SO2, 0.20 ppm O3, and 0.35 ppm SO, plus 0.05 ppm O3. Clonal repeatability estimates of 0.464 for SO2 plus O3, 0.620 for O3, and 0.642 for SO2 suggest that much of this variation between clones can be attributed to genetic differences in response to SO2 and O3.

Description: Year-to-year, geographical, and local variations in foliar concentrations of crude fat, nitrogen, total sugars, and starch and in foliar caloric value were determined for maturing, current-year needles of balsam fir (Abiesbalsamea L.). All except geographical variations proved to be statistically significant. Seasonal trends of chemical concentrations in maturing needles were in agreement with previous findings.Much of the variation in foliar caloric value could be explained by changes in foliar concentration of crude fat.Year-to-year changes in foliar nutrients may influence spruce budworm population dynamics.

Description: The use of the infiltration technique to estimate coniferous stomatal activity is investigated by comparing simultaneous measurements of stomatal infiltration pressure (inversely related to aperture) with leaf resistance determined using an aspirated diffusion porometer. The infiltration technique is shown to be incapable of accurately estimating leaf resistances but is able to describe adequately whether stomata are open or closed in both Douglas-fir and lodgepole pine. Furthermore, the infiltration technique allows the collection of information about stomatal status during times when the use of the diffusion porometer is impossible, such as periods marked by cold temperatures, dew, or precipitation.

Description: Survival and growth of coastal and interior provenances of 2-0 Douglas fir (Pseudotsugamenziesii (Mirb.) Franco), after storage for 16 weeks at different temperatures, were examined in two experiments. In the first experiment, plants of two coastal and two interior provenances were grown under three sets of environmental conditions. These provided non-hardy, partially hardy, and hardy stock of each provenance for storage at 2, −5, and −9 °C. Survival, after 8 weeks poststorage growth in the greenhouse, showed that no provenances survived storage well in a non-hardy condition, and that coastal provenances only stored well at 2 °C. Even interior provenances did not store well at −9 °C.In the second experiment plants of four coastal and four interior provenances were lifted on 10 November and again on 8 December for storage at 2 and −2 °C. Survival and stem relative growth rate measurements, made after plants had been allowed 8 weeks poststorage growth in the greenhouse, showed that 2 °C was less deleterious than −2 °C, and that coastal provenances were less tolerant of the lower temperature. Plants stored on 10 November showed better survival than those stored on 8 December, and there was no clear relationship between stem hardiness, measured by an electrical conductivity method, and survival after storage.In a third experiment, two coastal provenances of 2-0 Douglas fir were used to compare the effect of cold storage at 2 °C with exposure of heeled-in stock to open nursery conditions in satisfying the chilling requirement for bud flushing. Flushing of previously unchilled stock, which had been cold-stored for 12 weeks, occurred as rapidly as flushing of similar stock heeled-in in the open nursery for the same period.

Description: The distribution of sapwood and heartwood was analyzed at three different height levels in Abiesgrandis infested and non-infested with balsam woolly aphid. In non-infested trees, there was a highly significant regression between percentage heartwood age and disk age and a less significant regression between percentage heartwood area and disk area. Aphid infestation increased both the number of annual rings of heartwood and the heartwood area. The amount of heartwood in the infested trees was highly variable and dependent upon the degree of aphid infestation. Phenolic composition of A. grandis was similar to western hemlock, with heartwood containing matairesinol, hydroxymatairesinol, conidendrin, and an unknown phenolic glucoside. Sapwood contained several leucoanthocyanidins. Aphid infestation did not alter the phenolic composition of the heartwood, but it did cause the occurrence of a new phenolic in the sapwood. The possible causes of the increased amounts of heartwood in infested trees are discussed.

Description: In a work on soil variability within a given site, a detailed study was undertaken to determine the perturbation on soil horizons by a windfall. A representative windfall of the most frequent type was studied. The arrangement of soil horizons was described for this type of windfall qualified as normal. The mechanisms of this new arrangement of soil horizons are also described. Other types of windfall are briefly described and compared with the normal one. The importance of this phenomenon is discussed in view of the variations in soil properties between (bordering) profiles and its effect to soil development in a given ecosystem.

Description: Broadcast applications of 0, 100, 200 and 400 kg P/ha were made on two Chernozemic soils in 1965. The soils were cropped for 8 yr in a continuous wheat-flax rotation. In each year, crops grown on the phosphorus treatments yielded more and had higher phosphorus content than crops grown without added phosphorus. Over 8 yr of cropping, 100 kg P/ha was the most efficient treatment in increasing yield. Yield increases beyond 100 kg P/ha were either not significant or only marginally significant. Wheat used twice as much phosphorus as did flax. Together the two crops used approximately 30, 22 and 14% of the 100, 200 and 400 kg P/ha applied. The NaHCO3-extractable phosphorus level of the 100 kg P/ha treatment after 8 yr of cropping was reduced to about 8 kg P/ha which is considered to be inadequate for crop production. Soils treated with 200 and 400 kg P/ha contained high levels of NaHCO3-extractable P (20–54 kg P/ha) and little response in yield to additional P would be expected in the near future. Annual variation in yield and phosphorus uptake by the crops were affected by water supply. In years of high water supply, yield and phosphorus uptake were generally higher than in years of low water supply.

Description: Several laboratory methods for estimating lime requirements of acid soils were compared using 24 soils from Alberta and northeastern British Columbia and 15 from elsewhere in Canada. The Peech, Schofield, Woodruff and SMP (Shoemaker et al. 1971) buffer methods were equally well correlated with lime requirements for raising soil pH to 5.5 or 6, which in turn were highly correlated with the amounts of soluble and exchangeable Al and organic matter in the soils. The SMP buffer method is recommended for use as the diagnostic index of lime requirement to achieve pH 5.5 or 6 because of its speed and simplicity. A refinement is suggested for Alberta and northeastern B.C. soils on the basis that lime need not be added to achieve pH 5.5 but should be added to reduce Al below the toxic level for sensitive crops. The lime requirements to reduce Al in those soils were highly correlated with the amounts of 0.02 M CaCl2-soluble Al they contained and it is recommended that the 0.02 M CaCl2-soluble AI be used as the diagnostic index of lime requirement. Lime requirements related to SMP (pH) and 0.02 M CaCl2-soluble Al are presented.

Description: Some physical, chemical and mineralogical properties of five albic and six spodic horizons were studied in an attempt to relate their composition to their charge properties. The samples investigated contained less than 3% clay and had specific surface areas less than 30 m2/g. pH values measured in M NaF were lower than 9.5 for the A2 horizons but higher than 10.5 for all the Bir horizons studied. Mineralogy of the clay fraction was studied by using X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis along with selective chemical dissolution analyses. Chloritized vermiculite was the dominant phyllosilicate in the Bir samples, while montmorillonite dominated in the clay fraction of most of the A2 samples. Amorphous constituents, as determined by acid ammonium oxalate and 0.5 N NaOH extractions, represented up to 40% of the clay-sized fraction of some of the samples. Primary minerals such as quartz, feldspars and to a lesser extent hornblende and magnetite were the major constituents of the coarser fractions. The change in chemical and mineralogical compositions of the A2 and Bir horizons sharply reflected the variation that existed in their overall electrochemical behavior as shown by the potentiometric titration curves. A2 horizons usually behaved like a constant surface charge system, while the Bir samples reacted like a constant surface potential system with PZC values varying between pH 4.1 and 4.9.

Description: Bottom sediments from two streams draining agricultural land in New Brunswick were analyzed for organochlorine and organophosphorus insecticide residues. Most samples contained appreciable quantities of DDT plus metabolites (up to a total of 2.07 ppm), about one-third contained smaller quantities of endrin (up to 0.45 ppm) and approximately one-fifth contained dieldrin (up to 0.01 ppm). No other organochlorine and organophosphorus insecticides were detected. The highest residue levels were found in the watershed with the more intensive agricultural production and in proximity to fields producing intertilled crops.

Description: Granular monoammonium phosphate (500 μg P/g soil) was applied in the field to three soils of an Oxbow catena. Changes in the inorganic P forms controlling P concentration or intensity (Ie) in soil solution during the ensuing 2½ yr were determined by equilibrium solubility product and related quantity/intensity analyses. In the Calcareous and Orthic control soils, Ie was controlled by impure hydroxyapatite. After P addition, it was controlled by dicalcium phosphate dihydrate and octocalcium phosphate. Marked changes in the quantity of labile P caused negligible changes in values for Ie. Therefore, in these and similar Chernozemic soils, Ie should adequately reflect the availability of residual P to plants. In the Gleysol after P addition, Ie was determined by adsorbed P or by the solubility of aluminum/iron-bound P forms. For this and similar Chernozemic soils, the quantity/intensity data indicated that estimates of the availability of residual P will require a measurement of its capacity to maintain Ie at the root–soil interface against depletion by plant uptake rather than a measurement of Ie alone.

Description: not available

Description: The adsorption of Dyfonate (O-ethyl-S-phenyl ethylphosphonodithioate) was studied on humic acid (HA) saturated with various cations (Fe3+, Al3+, Cu2+, Zn2+, Co2+, Mn2+, Ni2+, Ca2+, Mg2+, and H+). The amount of Dyfonate adsorbed was affected by the cation with which the HA was saturated. The adsorption process could be described empirically by a Freundlich-type isotherm. The K and [Formula: see text] constants of the Freundlich equation decreased and increased, respectively, with increase in temperature. The data suggest a physical type of adsorption.

Description: Surficial chemico-hydrologic studies were conducted for 4 yr at eight sites in an Alberta irrigation district to determine the changes with time in soil salinity under existing management and to relate these changes to soil and groundwater characteristics. Both the electrical conductivity (EC) and sodium adsorption ratio (SAR) of the saturated soil extract increased over a 4-yr period for soils with glacial till within 60 cm of the surface. With till at depths of 150 cm and greater, the EC and SAR appeared to be stable. High water tables were encountered most frequently in the spring, when snow was melting, soil thawing, precipitation high, and evapotranspiration low. A correlation between salinity of subsoil and groundwater was evident. At one site, the EC of the groundwater increased with time, at four sites it was unchanged, and at three sites it decreased.

Description: Yield of barley (Hordeum vulgare L.) on land broken out of fescue (Festuca rubra) sod decreased with delay in time of breaking. Without nitrogen, but with phosphorus and potassium, the 4-yr (1969–72) mean yields were 2.89, 1.97, 1.61 and 1.24 tonnes/ha for plots broken in July, August, September and May, respectively. Increasing rates of nitrogen up to 90 kg N/ha resulted in yield increases which were nearly linear and similar for all breaking dates. With 90 kg N/ha yields were 4.09, 3.90, 3.28 and 2.96 tonnes/ha for plots broken in July, August, September and May, respectively. In a second experiment conducted for 2 yr, (1972 and 1974) an application of more than 90 kg N/ha did not result in further increases in yield of barley except in the plots broken in September. Uptake of N by barley (grain and straw) as with yield of barley grain was essentially linear and increased with increasing rates of N fertilizer. A delay in breaking from July to the following May resulted in a decrease of around 20 kg/ha of soil NO3-N in the top 60 cm of soil. Between September and May, the difference was only 1.2 kg/ha. This difference in soil NO3-N would not account for the yield differences obtained, since without fertilizer N the plots that were broken in September yielded about as much as those broken in May and fertilized with 22 kg N/ha. Soil moisture measurements in spring prior to seeding generally showed a decrease with delay in breaking. The differences were small and alone would not account for the wide variations in yields. It was observed that the seedbed condition was better with early than late breaking and that regrowth of fescue was markedly less on the plots broken in July than on the plots broken in September or May. The combined effect of these factors apparently limits the production of barley on recently broken grass sod.

Description: The techniques and procedures to be followed in the investigation of cadmium in soils and waters require careful evaluation in the interpretation of cadmium results. It was found that cadmium was adsorbed on the surfaces of rubber stoppers as well as on filter paper surfaces when in contact with solutions containing cadmium. The extent of error introduced through experimental techniques increased as the cadmium concentration in solution decreased.

Description: Determinations were made of the relative decomposition rates of samples taken from pasture plots on a blanket bog which had been drained, limed and variously fertilized for 8 yr. Under all three temperature regimes of incubations employed in the laboratory, samples of plots receiving fritted trace elements (FTE) and NPK fertilizers lost significantly less (22–29%) carbon than those of plots treated annually only with NPK. Subsequent measurements of bulk densities of the field plots confirmed the mitigating effect of FTE applications on biological degradation and humification of this organic soil. Chemical analyses and preliminary trials indicated that the increased Cu levels in the FTE-treated soils, although obviously not biocidal, may have inactivated some extracellular degradative enzymes in the soil at an accelerated rate, thus slowing degradation. Acid phosphatase activity was studied as an example. Indeed, this activity, both before and after laboratory incubation, was significantly lower in the FTE + NPK-treated material than in the one treated annually with NPK alone. The former also inactivated (in 20 h) 30% more of an added acid phosphatase preparation than did the latter. Also, this and several other organic soils lost significant proportions of their phosphatase activities upon incubation with 0.5% Cu. This treatment with Cu also curtailed the loss of carbon as CO2 from samples of the pasture plots on the Mesic Fibrisol.

Description: The forest floors of 20 soils supporting adult forest growth in New Brunswick were sampled and subjected to a study of P solubility in various reagents and P retention in the presence of variable amounts of Al. The organic surface accumulations contained from 430 to 1,280 ppm total P. After drying at 60 C, 6–28% of the total P was soluble in distilled water. Similar proportions of P were extracted with 0.002 N H2SO4, and slightly larger proportions by anion exchange resin. Extraction with 1 N HClO4 removed from 13 to 36% of the total P. Major portions of added [Formula: see text]were recovered by resin extraction from the organic substrates. Addition of Al reduced the recovery of added [Formula: see text] by various degrees, depending on the amount of Al added and origin of the organic sample.

Description: Principal component analysis was used to illustrate the evolution of chemical properties of a soil under sugar maple–beech forest, following two levels of thinning (30 and 50% of basal area). This multivariate analysis technique clearly showed that there were no significant differences between treated and untreated soils 10 yr after thinning.

Description: A preliminary thermodynamic characterization of water adsorbed on peat of sphagnum origin has been completed. The characterization has indicated that this organic material has a reactivity with respect to water which is similar to that of a montmorillonite clay. Under the relatively dry conditions of this study, less water was adsorbed by samples with a very low rubbed fibre content. The relative partial molar heat content of the adsorbed water approached the latent heat of fusion at water contents of about 16%. Additional measurements are required in the range of relative vapor pressures of 0.0–0.5 in order to determine if Halsey’s theory for adsorption on heterogeneous surfaces is applicable to the adsorption of water on peat.

Description: High rates of chemical fertilizer and barnyard manure were applied separately and together to barley (Hordeum vulgare L.) grown on three Gray Luvisolic soils for 6 successive yr. The fertilizers were applied annually with the N–P–K rates greater than 110–50–40 kg/ha. The manure was applied initially at 134 tonnes/ha and at 150 tonnes/ha before the fifth crop. Moisture use by the barley was measured for the last five crops. Average yields of barley were 1,530, 3,270 and 3,950 kg/ha for the nil, manure and fertilizer treatments, respectively. The manure + fertilizer treatment gave little or no further increase in yield over the fertilizer treatment. Efficiency of moisture use was generally more than doubled by the fertilizer and fertilizer + manure treatments. These treatments also greatly increased the use of soil moisture reserves, the greatest increase being for Beryl fine sandy loam, followed by Hazelmere loam and the least for Nampa clay loam. Soil moisture reserves at harvest time were depleted more under the fertility treatments than under the control plots. However, by the following spring, soil moisture reserves were nearly equal under the different plots having been replenished by fall and winter precipitation. These results show that on stubble land, moisture restricted yields much less than nutrients did and, on that basis, continuous cropping of Gray Luvisolic soils is discussed.

Description: In situ measurements of soil water matric potential and root xylem water potential in a Douglas fir forest using a Wescor HR-33T dew-point microvoltmeter and PT51-10 hygrometers are described. Root xylem water potential measurement required tangential insertion of the hygrometer into the root xylem and sensor protection from plant resins using gypsum powder. Soil water matric potential measurements were compared with matric potentials computed using gravimetric and neutron meter measurements of soil water content and laboratory soil water retention data, while root water potential measurements were compared with measurements made using the pressure chamber method. The comparisons showed agreement to within ± 0.3 bar over an 8-bar range. There was good agreement between soil water matric potentials determined using the dew-point and psychrometric modes of operation of the instrument. The root xylem water potential showed a marked diurnal response to atmospheric demand.

Description: Response of two forested Luvisolic soils to phosphorus fertilization was compared using chemical extractants known to be effective in removing certain soil phosphorus compounds. Fifteen months following fertilization application, the Mercoal series (Bisequa Luvisol) showed total phosphorus decreases in each of the soil horizons or layers sampled. To sampling depth, phosphorus concentrations in all but the NH4F extract (mainly aluminum phosphate) were lower in fertilized than in control samples. Vegetative uptake was considered to be mainly responsible for phosphorus decreases and movement, especially noticeable in the deeper mineral horizons. The Coalspur series (Orthic Luvisol) showed an appreciable phosphorus increase in the litter layer although both mineral horizons, Ae and Bt, exhibited losses. The Coalspur soil exhibited increases in soil phosphorus susceptible to all but the NH4F extractant. The data suggest a greater mobility and movement of soil phosphorus in these Luvisolic forest soils than usually observed in cultivated soils. Following fertilization, Mercoal probably had a greater number of phosphorus compounds (reaction products perhaps) more readily available than did the Coalspur.

Description: Undisturbed soil profiles from the middle of the B horizon topped with leaf litters and inoculated with earthworms were kept under laboratory conditions for 100 days. The soil properties examined were pH at three depths, and exchangeable calcium, exchangeable magnesium, nitrate nitrogen, available phosphorus, exchangeable potassium, organic matter and aggregate stability of a mixed soil profile. The effects of the earthworm treatments were to change the pH conditions of the soil, the amount of change varying with the species of earthworm present in a particular soil series. A decrease in exchangeable calcium and exchangeable magnesium in Uplands soil and available phosphorus in Dalhousie soil was also shown. The only effect of leaf litter treatments was to change nitrate nitrogen in Uplands and Dalhousie soils. We estimate that three- or fourfold the experimental time would be required for earthworms to sufficiently work the soil and significantly influence properties of an undisturbed soil core.

Description: Twenty-nine soil samples were selected within a field for similar pH (4.60–4.72) but with widely varying organic matter contents (3.5–20.5%). Exchangeable Al decreased while pH-dependent acidity increased with increasing organic matter content. The implication of these relationships for liming practices is discussed.

Description: The effectiveness of several commercial seeders and an experimental triple-disc press drill was assessed on a silt loam soil at Lethbridge over a 7-yr period on fields receiving chemical weed control instead of tillage between crops. The double- and triple-disc press drills generally failed to penetrate untilled surfaces adequately when soil bulk density in the upper 5 cm exceeded about 1.2 g/cm3 or when the quantity of surface residue exceeded about 3,700 kg/ha. Hoe openers penetrated the soil but failed to clear heavy residues when stubble and straw lengths were excessive (〉 25 cm). In 2 of the 7 yr, yields of spring wheat (Triticum aestivum L.) on small plots seeded with the double- and triple-disc drills were superior to those seeded with the wide-spaced hoe drill (1,159 vs. 721 kg/ha in 1969, and 667 vs. 573 kg/ha in 1973). Yield differences were primarily due to wild oats (Avena fatua L.), which germinated because of the tillage action of hoe openers, in ridge areas between rows and which, despite the use of herbicides, seriously reduced yields from wide-spaced rows (23 and 36 cm). In the other years, yields were similar for all seeding methods. On 0.4-ha chemical fallow fields, yields were up to 51% lower within sprayer wheel traffic areas (bulk densities of 1.2 g/cm3 or greater in the 0- to 5-cm soil layer) because of shallow seed placement when double-disc drills were used but not when hoe drills were used.

Description: Vorlex and linuron combination treatments of muck drastically reduced the population of molds, while those of the bacteria and actinomycetes remained practically unaffected. The reduction was due to Vorlex; linuron alone exerted an insignificant influence on the populations. Recovered fungi were not pathogenic and the population change had no detrimental effect on Lactuca sativa L. and Avena sativa L.

Description: There was no evidence of leaching of K below the 0- to 30-cm layer following addition of a total of 2,232 kg K/ha to a loam and a sandy loam soil in 3-yr field experiments. Grasses contained higher concentrations of K and recovered considerably more of the added K than did corn.

Description: The effects of single applications of 100, 200, and 400 kg/ha of P were measured under field conditions on Chernozemic soils in Manitoba and Saskatchewan for 8 yr. All applications of P increased the yield of wheat and increased the amount of available P in the soil. The addition of P with the seed did not increase the yield on plots that had received 100 kg/ha of P or more, except in 2 yr at one of the four test locations. On extremely P-deficient soils in Manitoba, 21% of the broadcast P (applied at 100 kg P/ha) was recovered by grain in 8 yr; the percent recovered was lower from the 200 and 400 kg P/ha at all sites (15 and 9%, respectively) but the amount of available P remaining in the soil was greater. Single large applications of 100 kg/ha of P were shown to be effective over the 8-yr period. Higher rates of application showed little advantage over 100 kg P/ha in the 8 yr but would probably remain effective for longer periods.

Description: Combined applications of ammonium nitrate (449 kg/ha) and gypsum (4.48 tonnes/ha) were added annually to a bromegrass sod for 4 yr. The soil was a Brown Solodized Solonetz with an exchangeable sodium percentage (ESP) of 17 and 33 in the Ap and Bnt horizons, respectively. The significant effects of the combined applications were to reduce exchangeable Na, increase water infiltration and depth of Ca penetration, and provide small increased yields over that of ammonium nitrate alone. Analysis of columnar peds from the Bnt horizon showed that inped penetration of Ca had occurred at the expense of Na. These studies indicate a synergistic effect, whereby the solubility and penetration of gypsum are enhanced by ammonium nitrate.

Description: Correlations were made among chemical criteria used for taxonomic soil classificaton. The compared tests were: oxalate Δ (Fe + Al), pyrophosphate-extractable (Fe + Al), oxalate-extractable Al, pH-dependent cation exchange capacity (ΔCEC), ratios of pyrophosphate-extractable (Fe + Al) over clay or over dithionite-extractable (Fe + Al), and finally soil pH measured in 1 M NaF. Significant correlations were found among various measured parameters. However, no single test was found to be reliable as a single criterion when applied to the taxonomic classification of Quebec soils. The two chemical tests, pyrophosphate-extractable (Fe + Al) and its ratio over clay, combined with morphologic criteria appeared useful for classifying Quebec Podzols. A few soils, which presented discrepancies from chemical criteria were found difficult to classify, thus suggesting the possibility of establishing new sub-groups in the Canadain soil taxonomic classification system.

Description: A method has been devised to relate the yields of wheat, oats and barley to the agroclimatic subregions of Alberta, the soil capability for agriculture and the soils of Alberta, using yield data supplied by the Alberta Hail and Crop Insurance Corporation. Four management practices are included: crops grown on stubble, fallow, stubble-fertilized and fallow-fertilized. Duncan’s multiple range test was used to test the validity of the differences in yields between the agroclimatic subregions, soil capability classes for agriculture, soil series and management practices. This information allowed for the development of economic assessment of a land resource which could be utilized for land evaluation and land use planning.

Description: An investigation was carried out on the uptake of several long-lived radioisotopes by grasses growing on uranium tailings. Field plots of creeping red fescue (Festuca rubra L.), reed canary grass (Phalaris arundinacea L.), redtop (Agrostis alba L.) and climax timothy (Phleum pratensis L.) which have been growing for 4 yr were sampled in this study. The tailings and the plant tissue were analyzed for uranium, thorium, radium-226, lead-210 and polonium-210. Sedimentation within the tailings area gave two zones: one of sands and one of slimes. The slimes contained significantly more radium-226, lead-210 and polonium-210 than the sands. There was no difference in uptake behavior by grasses growing in the sands and those growing in the slimes. Creeping red fescue (Festuca rubra L.) showed an anomalous uptake of lead-210, but other than this, all four grass species showed similar uptake behavior. Only uranium and radium-226 were significantly higher in the grasses from the tailings than the control.

Description: Electron spin resonance (ESR) spectrometry was used to determine weighted average equilibrium functions [Formula: see text] for water-soluble complexes formed between fulvic acid and divalent manganese. [Formula: see text] values ranged from 0.2 × 10−2 (at pH 6.15) to 0.5 × 10−3 (at pH 6.45) and were in excellent agreement with [Formula: see text] values determined previously for Mn–fulvic acid complexes by an ion-exchange method. The ESR method was found to be more sensitive, convenient and faster than the ion exchange procedure. From the data presented in this and in earlier publications it appears that MnII is bound simultaneously electrostatically and by hydrogen-bonding as Mn(OH2)62+ to fulvic acid donor groups in outer sphere complexing sites. These complexes are likely to be unsymmetrical.

Description: The herbicide atrazine was applied pre-emergence to corn plots which were drained by separate drains (average depth 70 cm). Water samples were collected from the tile outlets, extracted with chloroform, and the atrazine content determined by gas chromatography. The discharge of atrazine residues monitored over a 4-yr period ranged from 2.75 to 8.69 g/ha annually. The concentration varied between 0.5 and 3.50 μg/liter of water. Losses of atrazine were greater from plots under a continuous corn crop and a high fertility level than from plots under rotation corn and low fertility.

Description: Samples of granular materials illuminated with a 20 m Watt (average power) laser energy source at a wavelength of 337.1 nm differed in their fluorescence spectra over a wide range of wavelengths from approximately 380 to 660 nm. The fluorescent yield was usually higher with increased fineness of grain size and with increased concentration of clay (〉 10% of under 2-μ grain size). However, sandy soils containing a low content of clay (i.e. 

Description: Runoff from seven predominantly agricultural watersheds in southwestern Quebec and southeastern Ontario was monitored from May 1974 to May 1975 for total soluble phosphorus (TSP) Bray 2 extractable phosphorus, sediment and discharge. Although watershed unit area soluble P losses were small, only exceeding 1 kg/ha in watersheds with a high fraction of organic or impermeable soils, average stream TSP concentrations always exceeded the 10 μg P/liter value often considered a critical threshold in accelerating eutrophication. Sediment P losses were less than 1 kg/ha from any watershed but comprised from 14 to 80% of watershed P loss. Increased watershed area of row cropping (predominantly corn, potatoes) was associated with increased soluble but not sediment P loss. Decreased sediment P loss occurred from watersheds with a higher proportion of permeable soils.

Description: The amount of cultivated acid soil in Alberta and northeastern British Columbia was estimated from pH values of farm samples analyzed by the Alberta Soil Testing Laboratory, and the effect of soil acidity on crops was assessed from field experiments on 28 typical acid soils. The field experiments consisted of two cultivars of barley (Hordeum vulgare L.) and one cultivar each of rapeseed (Brassica campestris L.), red clover (Trifolium pratense L.) and alfalfa (Medicago sativa L.) grown with and without lime for 2 yr. There are about 30,000 ha of soils with a pH of 5.0 or less where soil acidity seriously restricts yields of all four crop species. There are approximately 300,000 ha with a soil pH of 5.1–5.5 where liming will on the average increase yields of alfalfa by 100%, yields of barley by 10–15%, and yields of rapeseed and red clover by 5–10%. There are a further 1,600,000 ha where soil pH ranges from 5.6 to 6.0 and liming will increase yields of alfalfa by approximately 50% and yields of barley, rapeseed and red clover by at least 4–5%.

Description: The degree of decomposition (humification) of 10 peats, ranging from undecomposed to completely decomposed, was determined by the following methods: (1) von Post’s method using 10 classes of humification, (2) pyrophosphate-soluble organic matter determination using an index derived from Munsell color charts, (3) unrubbed fiber content in percent of total, (4) rubbed fiber content in percent of total. All four methods provided reliable and useful information. The von Post method requires no instrumentation and is therefore most suitable for field use. It is the least time-consuming and the cheapest of the four methods. The pyrophosphate method is best suited to use in a laboratory. It does not always readily differentiate grades of well humified and completely humified peats. Both methods of determining fiber content require instrumentation and a steady, running stream of water. The rubbed fiber content more accurately characterizes the amounts of undecomposed fiber in peat. In the range of humic peats the two latter methods tend to differentiate fewer classes than does the von Post method. For the convenience of the reader the four methods are described in detail in the Appendix.

Description: To simulate the effect of dew formation on microbial growth in semiarid soils, air-dry loam was exposed to moisture condensation by incubating soil in a sine wave temperature incubator in which the diurnal temperature was 27.5 and 4 C and the relative humidity was 45% at 27.5 C. In an open system, condensation increased the soil moisture from about 1.4 to 4% (by weight) which is equivalent to a moisture suction of −1,930 and −200 bars, respectively. Even at such high suctions, condensation caused marked increases in bacteria and actinomycetes as assessed by plate and direct counts. A pure culture of Arthrobacter oxidans, a typical nonsporeforming soil bacterium, responded in a manner similar to the natural bacterial flora. Neither temperature per se, spore germination, nor contamination by airborne microorganisms was responsible for these increases. It was hypothesized that at such high suctions, moisture distribution in the soil must be heterogenous in order to permit bacterial growth.

Description: The average soil pH of 10 organic soils was significantly influenced by drying and the salt concentration of the suspending media. Accordingly, mean soil pH of field-moist and oven-dried soils was pH 5.0 and 4.5, 4.1 and 3.9, and 3.8 and 3.6 for soils suspended in water, 0.015 M CaCl2 and 1 M KCl. A significant treatment–soil interaction indicated that the soils responded differently to the treatments. No junction potentials were found when the ionic strength of the solution was 0.01 M CaCl2 equivalent or greater. Milli-equivalents exchangeable hydrogen (−0.984**), percent hydrogen saturation (−0.966**) milli-equivalents extractable bases (0.937**) and percent base saturation (0.957**) were more closely correlated with 1 M KCl pH values than with values in the other media. Liming influenced soil pH significantly on all field sites and within 8 h after application on two field sites. The influence of liming on soil pH tended to diminish the year after applications were made. Measured soil pH variability among treatments and replicates at various sampling dates ranged up to 1 pH unit during the growing season. However, it was about 0.2 pH unit on the control treatments with undetectable quantities of residual limestone. The quantity of reacted limestone was established at 25 and 40%, between 23 May and 31 July, on two sites (J.I.V. and S.B.). The reacted limestone was found to be proportional to the application rate.

Description: Grass root production is a major source of C entering Chernozemic soils. The influence of the initial chemical composition of the roots of three grass species on decomposition was studied in a laboratory incubation experiment. Roots of Stipa comata Trin. and Rupr., Stipa spartea Trin. var. curtiseta Hitchc., and Festuca scabrella Torr. were incubated at 28 C for 47 wk. Carbon dioxide production and percent loss of carbohydrate were inversely related to [(C:N) (% lignin)] (% carbohydrate−½). Percent loss of lignin, however, was directly proportional to this factor. This relationship was also found to fit data in the earlier literature. Decomposition rate appeared to be slower in the laboratory in the absence of soil than has been reported for decomposition rates in field soils. The data are discussed with reference to the dynamics of plant residues and organic matter in soil systems. It is postulated that the effect of soil in controlling decomposition may be as great as the effect of the substrate.

Description: The content of cadmium, cobalt, copper, mercury, manganese, nickel, strontium, lead and zinc in several agricultural soils in Alberta was investigated. The abundances of these heavy metals were found to be low and represent levels naturally present in uncontaminated soils. Both pedogenesis and nature of parent material influenced the levels of heavy metals in surface soil horizons. On a local scale, drainage and groundwater effects contributed significantly to heavy metal redistribution in soil. Levels of heavy metals were also determined in seeds and straw of cereal grain crops grown on the soils of this study. Vegetative samples generally contained low amounts of heavy metals and for some of the physiologically essential elements (Cu, Mn, Zn), amounts in the plant material were at or near deficiency levels. Amounts of cadmium, mercury and lead were generally significantly higher in straw than in respective seed samples.

Description: One hundred and sixty-eight forest stands in the northeastern United States with different histories of defoliation and responses to defoliation by the gypsy moth were compared by principal-components analysis (PCA) ordinations. The ordinations were based on tree structure-feature variables. PCA ordinations separated stands into meaningful groups that historically have been either susceptible or resistant to prolonged gypsy moth infestation. The best separation of resistant and susceptible stands occurred when the structure-feature variables were measured separately for tree species in different gypsy moth food-preference classes. Tree mortality after defoliation often was greater in the resistant wet bottom and mesic slope and ridge stands than in the susceptible dry ridge and sand stands. Our ordinations suggest that some stands, as a consequence of high oak mortality, may now be more resistant than before.

Description: The foliage from 11 Douglas-fir fertilizer installations in the American Pacific Northwest were chemically analyzed to find a possible parameter to predict response to nitrogen application. It was found that the trees with high foliar sulphate sulphur reserves had a high response to nitrogen fertilizer while those with low foliar sulphate sulphur reserves had a low response. The basis for the assessment was the known biochemical relationship between nitrogen and sulphur in protein and the necessity for adequate foliar sulphur concentrations for nitrogen to be utilized by the plant. Foliar sulphate sulphur concentration was found to be a better single parameter for determining fertilizer nitrogen requirements than foliar nitrogen concentration.

Description: Two samples taken from tropical volcanic surface soils and one sample from a Canadian Podzol subsurface soil were oxidized with H2O2 under conditions usually employed for the removal of organic matter from soils prior to mineralogical analyses. Between 65 and 82% of the C but only between 23 and 36% of the N in the initial organic matter in the three soils was oxidized to volatile and water-soluble products. Among the latter, small amounts of about 40 different aliphatic and aromatic compounds were identified, most of which were phenolic. Extraction with organic solvents removed n-alkanes and n-fatty acids from H2O2-resistant organic matter, but most of the latter consisted of humic substances strongly bonded to or absorbed on inorganic soil constituents. H2O2-resistant fractions accounted in the case of two soils, initially rich in organic matter, for 12.0 and 7.5% of the air-dry weights of peroxidized soils. The presence of such substantial amounts of H2O2-resistant organic matter may interfere with the dispersion and mineralogical analysis of peroxidized soils, especially those with high initial organic matter contents.

Description: Small clear-cuttings (elliptical, circular, and strip) were made in the commercial boreal forest in Quebec to improve black spruce (Piceamariana (Mill.) B.S.P.) reproduction.Five years after cutting, black spruce layers were as numerous as black spruce seedlings and total softwood reproduction averaged 26 710 stems per hectare (10 810 stems per acre) with 90% stocking. In some cases, white birch stems tripled between the 1st and 5th year after cutting, which may have an important effect on stand composition.Strip cuts gave more stems per hectare than circular or elliptical cuts but stocking was lower. Strips 40 m wide (130 ft) gave better results than those 80 m wide (260 ft).Stocking, although adequate in all these small clear-cuttings, appears to be a more critical factor in the success of softwood reproduction than is density.

Description: The development of a tree volume-estimating method for juvenile trees ranging from 1 to 10 m in height is described and application is suggested. Volume equations are given for coastal Douglas fir (Pseudotsugamenziesii (Mirb.) Franco), lodgepole pine (Pinusconiorta Dougl.), and two spruce species (Piceaengelmannii Parry and Piceaglauca (Moench) Voss) of British Columbia. The method features flexible diameter reference height and a height limit, beyond which the conventional diameter at breast height and volume estimating methods apply.

Description: Fire behavior observations with rates of spread up to 20 m/min (66 ft/min) have been recorded on 40 prescribed grass fires in central Washington and northern California. Physical parameters were also recorded describing the grass fuel array (fuel load, moisture content (≤ 15%), etc.), along with the wind speed (up to 8 km/h) and slope (near zero). These data were sufficient to allow a prediction of the fire spread rate, combustion zone depth, and flame length using the Rothermel fire spread model.A least squares fit of the observed versus the predicted results shows that positive agreement (slope = 1, intercept = 0) is supported for rate of spread. Flame length shows positive agreement for the intercept but not for slope. Combustion zone depth does not show positive agreement for either intercept or slope. The authors attribute the lack of positive agreement to less accurate measurements (ocular estimates) of the flame length and combustion zone depth.

Description: Foliage in mature Quercus spp. crowns was sampled by using a two-phase procedure. The first phase provided estimates of the total count of leaf clusters in the tree crowns. The second-phase sample provided information about the clusters such as dry weight, surface area, and leaf count.

Description: Calculations are presented giving biomass and quantities of nitrogen, phosphorus, potassium, calcium, and magnesium contained in soil, understory vegetation, and standing arboreal components of a low-site, immature Pseudotsugamenziesii (Mirb.) Franco ecosystem on southern Vancouver Island. For the standing arboreal crop, biomass and elemental content of the foliage, live and dead branches, wood, bark, and total tree were estimated, using the formula logeY = a + b logeD2H, where D = diameter breast height and H = total tree height.The soil component contained over 70% each of the total organic matter biomass and nitrogen, calcium, and magnesium content in the ecosystem. Although the soil also contained large quantities of potassium and phosphorus, the vegetative component significantly increased in importance with regard to these two elements. Biomass and nutrient distribution patterns within the standing arboreal crop are discussed in terms of elemental concentrations and distribution between components over the diameter range encountered. The distribution of biomass and the total elemental content among the various ecosystem components are discussed and comparisons are made with related studies.

Description: By cytochemical and electron microscopic methods, the emerging radicle of Pinusbanksiana Lamb. was shown to contain an abundance of food reserves largely proteins, lipids, and starch grains. After 4 days of imbibition, the food reserves were dispersed to the daughter cells that tended to form through a sequence of divisions, linear arrays of adhering cells. The main cytochemical changes were associated with the later stages of imbibition and the consumption of carbohydrates and nitrogenous compounds for the synthesis of newly dispersed macromolecules. Peroxidase (EC 1.11.1.7) not found to any significant extent in the dry embryo, appeared by day 4 in the root cap and epidermal cells. As for DNA synthesis, cells of the quiescent zone were shown by autoradiography to incorporate very little [methyl-3H]thymidine. By contrast, most cells in the radicle incorporated thymidine in advance of the first wave of cell division between 3 to 4 days.The initial tight packing of subcellular organelles and the high lipid content of dry cells made the evaluation of subcellular changes difficult. In the nucleus and cytoplasm, the increase of ribosomes and polysomes was supported by the increased cytoplasmic staining for total RNA and acidic proteins. In emerging radicles, the overall redistribution of organic reserves and the associated subcellular reorganization related to the tactical displacement of cells and to new channels for the initial uptake of water and nutrients from the soil.