Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Feb 14;109(7):2423-7.
doi: 10.1073/pnas.1111576109. Epub 2012 Jan 30.

Regional drought-induced reduction in the biomass carbon sink of Canada's boreal forests

Zhihai Ma  1 , Changhui Peng, Qiuan Zhu, Huai Chen, Guirui Yu, Weizhong Li, Xiaolu Zhou, Weifeng Wang, Wenhua Zhang
Affiliations

Regional drought-induced reduction in the biomass carbon sink of Canada's boreal forests

Zhihai Ma et al. Proc Natl Acad Sci U S A. .

Abstract

The boreal forests, identified as a critical "tipping element" of the Earth's climate system, play a critical role in the global carbon budget. Recent findings have suggested that terrestrial carbon sinks in northern high-latitude regions are weakening, but there has been little observational evidence to support the idea of a reduction of carbon sinks in northern terrestrial ecosystems. Here, we estimated changes in the biomass carbon sink of natural stands throughout Canada's boreal forests using data from long-term forest permanent sampling plots. We found that in recent decades, the rate of biomass change decreased significantly in western Canada (Alberta, Saskatchewan, and Manitoba), but there was no significant trend for eastern Canada (Ontario and Quebec). Our results revealed that recent climate change, and especially drought-induced water stress, is the dominant cause of the observed reduction in the biomass carbon sink, suggesting that western Canada's boreal forests may become net carbon sources if the climate change-induced droughts continue to intensify.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Locations of the 96 forest plots in Canada's boreal forest. The red and black circles represent plots with respectively decreasing and increasing rates of biomass change. The size of the circle is proportional to the plot-specific slope of the ordinary least-squares regression for the rate of biomass change as a function of the calendar year. Thus, the circle size reflects the rate of annual change in biomass. The background colors of green and light green represent the boreal and hemiboreal regions, respectively. In total, 80 plots (83% of the 96 forest plots) were located in the boreal region and 16 (17%) were located in the hemiboreal region. A total of 70 plots were located in the western region (Alberta, Saskatchewan, and Manitoba) and 26 were located in the eastern region (Ontario and Quebec). In total, 89% of the plots (62/70) in the western region and 46% of the plots (12/26) in the eastern region experienced decreasing rate of biomass change. The shapefiles defining Canada's boreal and hemiboreal zones were developed by J. P. Brandt of Natural Resources Canada (SI Appendix, ref. S16) and were obtained from the agency's Web page (http://canadaforests.nrcan.gc.ca/download; accessed December 23 2011).
Fig. 2.
Fig. 2.
(A) Annual rate of change in aboveground biomass for all Canadian boreal forest plots combined from 1963 to 2008. The dotted lines represent 95% confidence intervals. (B) Annual rate of change of aboveground biomass for the western and eastern regions. (C) Annual rate of change in stand-age–corrected aboveground biomass for all Canadian boreal forest plots combined from 1963 to 2008. The dotted lines represent 95% confidence intervals.
Fig. 3.
Fig. 3.
Plots of the rate of biomass change as a function of stand age for the western and eastern regions. The black line represents the modeled trends from the ordinary least-squares regression model. The red, green, light blue, and blue dots represent the first, second, third, and fourth census, respectively. n is number of censuses for all of the age ranges.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Denman KL, et al. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon, et al., editors. Cambridge: Univ of Cambridge Press; 2007. pp. 501–587.
    1. Angert A, et al. Drier summers cancel out the CO2 uptake enhancement induced by warmer springs. Proc Natl Acad Sci USA. 2005;102:10823–10827. - PMC - PubMed
    1. Stephens BB, et al. Weak northern and strong tropical land carbon uptake from vertical profiles of atmospheric CO2. Science. 2007;316:1732–1735. - PubMed
    1. Piao S, et al. Net carbon dioxide losses of northern ecosystems in response to autumn warming. Nature. 2008;451:49–52. - PubMed
    1. Dixon RK, et al. Carbon pools and flux of global forest ecosystems. Science. 1994;263:185–190. - PubMed

Publication types

LinkOut - more resources