ISSN:
1573-5036
Keywords:
coarse root excavation
;
core method
;
fine root biomass
;
quantitative pits
;
Quercus douglasii
;
root distribution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract This research adds to the limited data on coarse and fine root biomass for blue oak (Quercus douglasii Hook and Arn.), a California deciduous oak species found extensively throughout the interior foothills surrounding the Central Valley. Root systems of six blue oak trees were analyzed using three methods — backhoe excavation, quantitative pits, and soil cores. Coarse root biomass ranged from 7 to 177 kg per tree. Rooting depth for the main root system ranged from 0.5 to 1.5 m, with an average of 70% of excavated root biomass located above 0.5 m. Of the total biomass in excavated central root systems, primary roots (including burls) accounted for 56% and large lateral roots (〉 20 mm diameter) accounted for 36%. Data from cores indicated that most biomass outside of the root crown was located in fine roots and that fine root biomass decreased with depth. At surface depths (0–20 cm), small-fine (〈 0.5 mm diameter) roots accounted for 71%, large-fine (0.5–2.0 mm) for 25%, and coarse (〉 2 mm) for 4% of total root biomass collected with cores. Mean fine root biomass density in the top 50 cm was 0.43 kg m−3. Fine root biomass did not change with increasing distance from the trees (up to approximately 5 m). Thus, fine roots were not concentrated under the tree canopies. Our results emphasize the importance of the smallest size class of roots (〈0.5 mm), which had both higher N concentration and, in the area outside the central root system, greater biomass than large fine (0.5–2.0 mm) or coarse (〉 2.0 mm) roots.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1004653932675
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