Publication Date:
2013-11-26
Description:
[1] Canada's forests play an important role in the global carbon cycle through carbon (C) storage and C exchange with the atmosphere. While estimates of aboveground biomass have been improving, little is known about belowground C storage in root biomass. Here we estimated the contribution of roots to the C budget of Canada's 2.3x10 6 km 2 managed forests from 1990 to 2008 using the empirical modelling approach of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) driven by detailed forestry datasets from the National Forest C Monitoring, Accounting and Reporting System (NFCMARS). The estimated average net primary production ( NPP ) during this period was 809 Tg C yr -1 (352 g C m 2 yr -1 ) with root growth and replacement of turnover contributing 39.8 % of NPP . [2] Average heterotrophic respiration ( R h ) was 738 Tg C yr -1 (321 g C m -2 yr -1 ), which resulted in a net ecosystem production ( NEP ) value of 31 g C m -2 yr -1 (71 Tg C yr -1 ), and on average only 8.7% of NPP remained in the system as NEP . Estimated average root C stocks were 2.38 Pg (1235 g C m -2 ), mostly in coarse roots (≥ 5 mm diameter), and had an average root to shoot percentage (belowground to aboveground biomass) of 25.6%. Detailed monitoring of C exchange between forests and the atmosphere and an improved understanding of the belowground processes and their response to environmental changes are needed to improve our understanding of the terrestrial C budget
Print ISSN:
0886-6236
Electronic ISSN:
1944-9224
Topics:
Biology
,
Chemistry and Pharmacology
,
Geography
,
Geosciences
,
Physics
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