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Title: Seasonality and partitioning of root allocation to rhizosphere soils in a midlatitude forest

Root growth, respiration, and exudation are important components of biogeochemical cycles, yet data on the timing and partitioning of C to these processes are rare. As a result, it is unclear how the seasonal timing, or phenology, of root C allocation is affected by the phenology of its component processes: growth of root tissue, respiration, mycorrhizal allocation, and exudation of labile C. The objective of this study was to estimate the phenology and partitioning of C belowground across the growing season in a midlatitude forest located in central Massachusetts. Fine and coarse root production, respiration, and exudation were summed to estimate a monthly total belowground C flux (TBCF) in two hardwood stands dominated by Quercus rubra and Fraxinus americana, respectively, and one conifer stand dominated by Tsuga canadensis. We observed significant stand-level differences in belowground C flux and the partitioning of C to root growth, mycorrhizal fungi, exudation, and respiration. The deciduous hardwood stands allocated C belowground earlier in the season compared to the conifer-dominated stand. The deciduous stands also allocated a greater proportion of TBCF to root growth compared to the conifer-dominated hemlock (T. canadensis) stand. Of the three stands, red oak partitioned the greatest proportion of TBCF (~50%)more » to root growth, and hemlock the least. Low root growth rates in hemlock may be related to the arrival and spread of the invasive pest, hemlock wooly adelgid (Adelges tsugae), during the study period. Ongoing research in the eastern hemlock stand may yet determine how whole tree allocation and partitioning change as a result of this infestation.« less
Authors:
 [1] ;  [1]
  1. Boston Univ., MA (United States). Dept. of Biology and PhD Program in Biogeoscience
Publication Date:
Grant/Contract Number:
AC02-05CH11231; EF-1065029; DEB-0743564
Type:
Published Article
Journal Name:
Ecosphere
Additional Journal Information:
Journal Volume: 7; Journal Issue: 11; Journal ID: ISSN 2150-8925
Publisher:
Ecological Society of America
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; belowground allocation; C budget; Fraxinus americana; Harvard Forest; midlatitude forest; minirhizotron; phenology; Quercus rubra; rhizosphere; root growth; Tsuga canadensis
OSTI Identifier:
1332008
Alternate Identifier(s):
OSTI ID: 1336826; OSTI ID: 1377554