ALBERT

Description: With a total area of several million hectares, mountain forests of Norway spruce ( Picea abies (L.) Karst.), silver fir ( Abies alba Mill.) and European beech ( Fagus sylvatica L.) connect the beech-covered lowlands and spruce-dominated alpine regions and still represent the most natural though managed forests in Europe. For sustaining their unique functions and services, their natural gap dynamics are emulated by the combined shelterwood–femel-coupe system. In the 1970s, 22 long-term experimental plots were established in the Bavarian Alps in order to substantiate the formerly mainly experience-based silvicultural prescriptions. After more than 40 years of successive surveys including the integrated evaluation of the old stands and the measurement of natural regeneration, analyses reveal: (1) The reduction of overstorey density is generally associated with a proportional reduction of the overstorey stand growth. So, the recommended 20–40 per cent density reduction of a combined shelterwood–femel coupe may reduce the mean annual increment also by ~20–40 per cent, but part of this loss is compensated by the additional growth of the regeneration. (2) Over time, the natural regeneration is continuously augmented by new recruitment of seedlings and saplings. (3) However, even 40 years after initiating regeneration, spruce is rare in the regeneration compared with fir, beech and other broadleaved species. Further observation will show whether spruce will catch up with the other species or whether it requires either larger disturbances than gap and femel coupes, or possibly planting. Based on these findings, a refined shelterwood–femel-coupe system is proposed and its advantages and disadvantages are discussed.

Description: Partial cutting practices are increasingly used in boreal forests for two major reasons: (1) maintaining age structure and tree diameter distribution according to the principles of ecosystem-based management and (2) increasing tree growth by decreasing competition. This study evaluated the effects of three different partial cutting treatments applied to even- and uneven-aged black spruce ( Picea mariana (Mill.) B.S.P.) stands in north-eastern Quebec, Canada. The effect of partial cutting was assessed by comparing treated and control plots in terms of age structure, diameter and spatial distribution, amount of deadwood and tree radial growth. Age structure and diameter distribution were not different from control plots after partial cuttings applied in both uneven-aged and even-aged stands, but lower deadwood basal area was observed. Tree radial growth generally increased in uneven-aged stands but can be limited by tree age and inter-tree competition. In even-aged stands, tree removal was more uniformly distributed and the overall reduction in inter-tree competition resulted in an increased tree radial growth. Overall, these results suggest that the studied partial cuttings were adequate for maintaining structural attributes and increasing tree growth, but adjustments should be made to treatments to increase the amount of deadwood to a level observed in natural forests and to lower inter-tree competition.

Description: The general belief that intense regeneration measures are financially viable and essential for high sustained yields of commercial forest products has been inadequately tested. This field experiment evaluates effects of three different regeneration intensities 24–27 years after clear-cutting of 14 sites across Sweden. The treatments, designated high (HI), normal (NI) and low (LI), respectively, consisted of: mechanical site preparation and planting of large seedlings at 2 x 2 m spacing, with supplemental planting and pre-commercial thinning (PCT) when deemed necessary; standard local practices; and natural regeneration with no site preparation, artificial regeneration or PCT. Average crop seedling densities were highest and lowest (3359 and 1662 ha –1 ) under the HI and LI treatments, respectively, 4–8 growing seasons after planting. After 24–27 years, HI also resulted in higher mean stem volume (90 m 3 ha –1 ) than LI (36 m 3 ha –1 ) but was not significantly different from NI (65 m 3 ha –1 ) and increasing the regeneration intensity was not consistently positive. In some cases, high planted seedling mortality and generally abundant natural regeneration resulted in minor (or no) differences between the treatments. The results illustrate that current Swedish regeneration standards may need revision in order to reflect contemporary societal and commercial demands.

Description: A healthy, productive and resilient workforce is important to any industry, and supporting the wellbeing of workers is a key factor in achieving this. Worldwide, the forest industry is amongst the most physically dangerous industries to work in. Workplace health and safety strategies have traditionally focused on improving the physical safety of forestry workplaces. It is equally important to consider the broader wellbeing of workers, not only to ensure their quality of life, but also to support a healthy and sustainable workforce with low turnover. To do this, it is critical to understand the work-related factors that affect worker wellbeing. We examine this via a survey of workers in the Australian forest industry. We find that work-related factors known to influence wellbeing in other industries, such as income, job security and workplace culture, are strongly correlated with forest worker wellbeing, that negative perceptions of the forest industry by those outside it are associated with lower levels of worker wellbeing and that the extent to which a forest industry worker has a strong work-related social identity is associated with their wellbeing. Our findings highlight the importance of implementing workplace strategies that consider wellbeing in broader terms than the traditional focus on physical safety.

Description: Botryosphaeria canker is likely the most injurious disease for cork production in the Mediterranean Basin. The exclusion of Benomyl, the standard commercial product used to prevent Botryosphaeria canker, from the EU Pesticide Database in 2003 necessitates the search for new alternatives to prevent cork oak cankering. In vitro experiments showed that every fungicide tested at 10 3 mg l –1 active ingredient was effective in reducing mycelial growth of Diplodia corticola . An initial field experiment showed that cork oak trunks sprayed with Thiophanate-methyl, Carbendazim, Difenoconazole, Pyraclostrobin or Copper-Calcium Sulphate under low-humidity environmental conditions exhibited significant decreases in the number and length of trunk lesions, 3 years post-treatment, compared with untreated trees. A second field experiment conducted under extremely wet conditions showed that only Thiophanate-methyl was effective, 2.5 years after treatments, when sprayed just after peeling. Finally, in a third field experiment, under wet conditions, the preventive effectiveness of Thiophanate-methyl, Copper-Calcium Sulphate and a mix of both fungicides was confirmed, although no synergistic effect of the mixture was measured. Copper-Calcium Sulphate or Thiophanate-methyl, when applied immediately after trunk peeling, is effective for preventive control of Botryosphaeria canker on cork oak and may be considered as an effective replacement for Benomyl.

Description: Forests and trees throughout the world are increasingly affected by factors related to global change. Expanding international trade has facilitated invasions of numerous insects and pathogens into new regions. Many of these invasions have caused substantial forest damage, economic impacts and losses of ecosystem goods and services provided by trees. Climate change is already affecting the geographic distribution of host trees and their associated insects and pathogens, with anticipated increases in pest impacts by both native and invasive pests. Although climate change will benefit many forest insects, changes in thermal conditions may disrupt evolved life history traits and cause phenological mismatches. Individually, the threats posed to forest ecosystems by invasive pests and climate change are serious. Although interactions between these two drivers and their outcomes are poorly understood and hence difficult to predict, it is clear that the cumulative impacts on forest ecosystems will be exacerbated. Here we introduce and synthesize the information in this special issue of Forestry with articles that illustrate the impacts of invasions of insects and pathogens, climate change, forest management and their interactions, as well as methods to predict, assess and mitigate these impacts. Most of these contributions were presented at the XXIV IUFRO World Congress in 2014.

Description: Puccinia psidii is a major threat to members of the Myrtaceae worldwide. New Zealand is still free of P. psidii but possesses significant Eucalyptus plantations as well as valuable native tree species such as Metrosideros excelsa and Leptospermum scoparium that could be at risk in the event of an incursion. As part of preparing for a potential incursion, we generated a barcode reference library for 〉100 diverse species of Myrtaceae occurring in New Zealand by sequencing internal transcribed spacer (ITS), external transcribed spacer (ETS) and maturase K ( matK ), or by obtaining relevant sequences from GenBank. The Myrtaceae DNA barcoding database will enable rapid identification of large numbers of host species in the event of a myrtle rust incursion. We undertook a comparative analysis of the ability for the three mentioned loci to discriminate species. Interspecific divergence was assessed by mean interspecific distance, prime and minimum interspecific distance; intraspecific variation was evaluated by mean intraspecific difference, and coalescent depth. Overall identification efficiency of the three loci sequenced was determined using BLAST1 and Near Distance methods. Barcoding gaps between inter- and intraspecific divergences were also analysed. ITS and ETS share similar mean interspecific distance, prime and minimum interspecific distance values – both higher than obtained for matK . In contrast, in terms of intraspecific variation, matK had higher values than ITS and ETS in all three metrics analysed. ITS had the highest identification success rate for species followed by matK and ETS, respectively, as measured by BLAST1 and Near Distance methods. Overall identification success rate increases when a combination of ITS and matK in particular is used. The sequence data are not only a valuable reference collection for a myrtle rust response but also a national botanical resource.

Description: Future forests are being shaped by changing climate and disturbances. Climate change is causing large-scale forest declines globally, in addition to distributional shifts of many tree species. Because environmental cues dictate insect seasonality and population success, climate change is also influencing tree-killing bark beetles. The mountain pine beetle, Dendroctonus ponderosae , is a major disturbance in Pinus forests of the western US. Using a mechanistic, phenology-based demographic model driven by downscaled daily temperature data, we describe recent and future spatial and temporal thermal suitability for mountain pine beetle population growth in a topographically complex region. Trends in model-predicted growth rates among Global Climate Models were similar and suggest that, relative to future trends, mountain pine beetle population growth within the past 60 years was most optimal at middle elevations and least optimal at the lowest and highest elevations. This trend aligns with observed mountain pine beetle-caused tree mortality that was greatest at middle elevations between 1997 and 2013, as estimated from Aerial Detection Surveys. However, thermal suitability for optimal phenological synchrony was predicted to shift in recent years, and by the end of the century, the best thermal habitats for mountain pine beetle will be at the lowest and highest elevations. Mechanistic demographic models are valuable tools for modelling future thermal regimes that may be both beneficial and maladaptive for mountain pine beetle population growth and subsequent tree mortality.

Description: Forest degradation is a major issue for policy-makers that is exacerbated by no clear and globally accepted definition of the term. For forest managers, a loss of forest productive capacity is one form of forest degradation. We present a quantitative method to assess forest degradation from a productivity perspective. Our method uses a standard stocking chart and calculation methods based on standard forest inventory data, to derive a clear threshold value for stocking, below which a forest should be considered degraded. The method is illustrated using the example of a self-regenerating Nothofagus production forest type from Chile. For that forest type, we determined that harvesting trees to below a specific basal area relative to site type, resulted in a loss of resilience, an unpredictable shift in ecosystem state, and a degraded condition. Our method illustrates how over-harvesting can degrade the long-term productivity of a stand and forest resilience. Nevertheless, it is important to consider that forests can also be degraded from other perspectives, such as loss of biodiversity, carbon, or protective functions as a result of excessive disturbances. Ecosystem management requires that managers consider degradation from a range of perspectives. We see the quantified approach used here as a way to provide practitioners with, in part, a transition from sustained yield to ecosystem management with an ultimate objective of providing a pathway towards adaptive management of complex systems and avoiding degradation.

Description: The Asian longhorned beetle (ALB), Anoplophora glabripennis (Coleoptera: Cerambycidae), is one of the most harmful invasive species in Europe and North America, causing enormous economic damage to broadleaved trees growing in urban parks and gardens. As a quarantine species, everywhere it has been introduced ALB has led to the application of expensive eradication programmes often associated with additional indirect costs due to the loss of ornamental value connected with the presence of trees in urban areas. The aims of this article are to quantify the impact of ALB in terms of tree mortality and their ornamental value during the first year eradication of an infestation in Northern Italy, and to perform an economic assessment of the eradication programme vs inaction. During the first year of eradication 367 ALB infested trees were removed from the infestation area at a total cost of about 48 000, comprising scientific advice (21 per cent), tree survey (38 per cent) and plant removal (41 per cent). The ornamental value of the infested trees was assessed at about 850 per tree. The ALB eradication programme allowed a reduction of 52 per cent of the damage expected in the following year, corresponding to an ornamental value of about 300 000. The ornamental value of the saved trees was ~6 times higher than the costs for their protection.