| Title | Annual carbon balance of Canada's forests during 1895-1996 |
| |
| Author | Chen, J; Chen, W ;
Liu, J; Cihlar, J; Gray, S |
| Source | Global Biogeochemical Cycles; vol. 14, no. 3, 2000 p. 839-849, https://doi.org/10.1029/1999GB001207 |
| Year | 2000 |
| Alt Series | Natural Resources Canada, Contribution Series 20181886 |
| Publisher | Wiley-Blackwell |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | geophysics; remote sensing |
| Program | Climate Change
Geoscience |
| Released | 2000 09 01 |
| Abstract | This paper reports annual carbon (C) balance of Canada's forests during 1895-1996 estimated using the Integrated Terrestrial Ecosystem C-budget model (InTEC) [Chen et al. this issue]. During 1895-1910,
Canada's forests were small sources of 30±15 Tg C yr-1 due to large disturbances (forest fire, insect-induced mortality, and harvest) in late nineteenth century. The forests became large sinks of 170±85 Tg C yr-1 during 1930-1970, owing to forest
regrowth in previously disturbed areas and growth stimulation by nondisturbance factors such as climate, atmospheric CO2 concentration, and N deposition. In recent decades (1980-1996), Canada's forests have been moderate sinks of 50±25 Tg C yr-1, as
a result of a tradeoff between the negative effects of increased disturbances and positive effects of nondisturbance factors. The nondisturbance factors, in order of importance, are (1) atmospheric N deposition (measured by a national monitoring
network), (2) net N mineralization and fixation (estimated from temperature and precipitation records), (3) growing season length increase (estimated from spring air temperature records), and (4) CO2 fertilization (estimated from CO2 records using a
leaf-level photosynthesis model). The magnitudes of modeled nondisturbance effects are consistent with simulation results by the Carnegie-Ames-Stanford Approach (CASA) and are also in broad agreement with flux measurements above mature forest stands
at several locations in Canada. Results for the disturbance effects agree with a previous study [Kurz and Apps, 1996]. The overall C balance from InTEC generally agrees with that derived from tree ring data [Auclair and Bedford, 1997] and from forest
inventories. The combination of our result and that of Houghton et al. [1999] for the United States suggests that North America (> 15°N) was probably a C sink of 0.2-0.5 Pg C yr±-1 during 1980s, much less than that of 1.7 Pg C yr±-1 estimated by
Fan et al. [1998] using an atmospheric inversion method. |
| GEOSCAN ID | 312241 |
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