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Simulating the carbon balance of a temperate larch forest under various meteorological conditions.

Toda M, Yokozawa M, Sumida A, Watanabe T, Hara T - Carbon Balance Manag (2007)

Bottom Line: An increase in air temperature by 3 degrees C (5 degrees C) reduces cumulative net primary production by 21.3% (34.2%).However, the positive effects of CO2 enrichment (2 x CO2) outweigh the negative effects of warming (<5 degrees C).These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5 degrees C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biosphere Dynamics Research Group, Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan. todam@pop.lowtem.hokudai.ac.jp

ABSTRACT

Background: Changes in the timing of phenological events may cause the annual carbon budget of deciduous forests to change. Therefore, one should take such events into account when evaluating the effects of global warming on deciduous forests. In this article, we report on the results of numerical experiments done with a model that includes a phenological module simulating the timing of bud burst and other phenological events and estimating maximum leaf area index.

Results: This study suggests that the negative effects of warming on tree productivity (net primary production) outweigh the positive effects of a prolonged growing season. An increase in air temperature by 3 degrees C (5 degrees C) reduces cumulative net primary production by 21.3% (34.2%). Similarly, cumulative net ecosystem production (the difference between cumulative net primary production and heterotrophic respiration) decreases by 43.5% (64.5%) when temperatures are increased by 3 degrees C (5 degrees C). However, the positive effects of CO2 enrichment (2 x CO2) outweigh the negative effects of warming (<5 degrees C).

Conclusion: Although the model was calibrated and validated for a specific forest ecosystem, the implications of the study may be extrapolated to deciduous forests in cool-temperate zones. These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5 degrees C.

No MeSH data available.


(a) Simulated seasonal and annual variations in gross primary production (GPP) and net primary production (NPP) and LAI in the Larix kaempferi stand. The vertical axes on the left- and right-hand sides are employed for GPP, NPP and LAI, respectively. LAIs observed in 1982, 1983 and 1984 are also plotted in this figure. (b) Simulated seasonal and annual variations in leaf respiration (Rleaf) and air temperature. The vertical axes on the left- and right-hand sides are employed for Rleaf and air temperature, respectively.
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Figure 2: (a) Simulated seasonal and annual variations in gross primary production (GPP) and net primary production (NPP) and LAI in the Larix kaempferi stand. The vertical axes on the left- and right-hand sides are employed for GPP, NPP and LAI, respectively. LAIs observed in 1982, 1983 and 1984 are also plotted in this figure. (b) Simulated seasonal and annual variations in leaf respiration (Rleaf) and air temperature. The vertical axes on the left- and right-hand sides are employed for Rleaf and air temperature, respectively.

Mentions: The simulated annual gross primary production (GPP) and net primary production (NPP) within the forest in our study over 7 years were 32.6 and 12.1 on average in the range from 31.8 to 33.9 and from 10.8 to 14.7 (ton ha-1 year-1), respectively (Fig. 2(a)). Both GPP and NPP have a similar seasonal trend, i.e., two peaks in spring and autumn. A large decrease in GPP and NPP was shown in summer. The decrease was caused by the increase in leaf respiration (Rleaf) which is mainly controlled by a seasonal change in air temperature (Fig. 2(b)). Rleaf was seven times as large as woody organ's respiration rates (stem and root) and 1.8 times larger than soil respiration on average. Therefore, averaged NPP/GPP was 0.37. In addition, the NPP simulated in the present study was consistent with the results referred to in [32], who summarized NPPs estimated in many Larix forests in the cool-temperate zone in China, and was equivalent to those obtained in other deciduous forests (e.g., 10 ton ha-1 year-1 in the case of a mixed forest which consisted of sugar maple, American beech, and yellow birch in [33]).


Simulating the carbon balance of a temperate larch forest under various meteorological conditions.

Toda M, Yokozawa M, Sumida A, Watanabe T, Hara T - Carbon Balance Manag (2007)

(a) Simulated seasonal and annual variations in gross primary production (GPP) and net primary production (NPP) and LAI in the Larix kaempferi stand. The vertical axes on the left- and right-hand sides are employed for GPP, NPP and LAI, respectively. LAIs observed in 1982, 1983 and 1984 are also plotted in this figure. (b) Simulated seasonal and annual variations in leaf respiration (Rleaf) and air temperature. The vertical axes on the left- and right-hand sides are employed for Rleaf and air temperature, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1904217&req=5

Figure 2: (a) Simulated seasonal and annual variations in gross primary production (GPP) and net primary production (NPP) and LAI in the Larix kaempferi stand. The vertical axes on the left- and right-hand sides are employed for GPP, NPP and LAI, respectively. LAIs observed in 1982, 1983 and 1984 are also plotted in this figure. (b) Simulated seasonal and annual variations in leaf respiration (Rleaf) and air temperature. The vertical axes on the left- and right-hand sides are employed for Rleaf and air temperature, respectively.
Mentions: The simulated annual gross primary production (GPP) and net primary production (NPP) within the forest in our study over 7 years were 32.6 and 12.1 on average in the range from 31.8 to 33.9 and from 10.8 to 14.7 (ton ha-1 year-1), respectively (Fig. 2(a)). Both GPP and NPP have a similar seasonal trend, i.e., two peaks in spring and autumn. A large decrease in GPP and NPP was shown in summer. The decrease was caused by the increase in leaf respiration (Rleaf) which is mainly controlled by a seasonal change in air temperature (Fig. 2(b)). Rleaf was seven times as large as woody organ's respiration rates (stem and root) and 1.8 times larger than soil respiration on average. Therefore, averaged NPP/GPP was 0.37. In addition, the NPP simulated in the present study was consistent with the results referred to in [32], who summarized NPPs estimated in many Larix forests in the cool-temperate zone in China, and was equivalent to those obtained in other deciduous forests (e.g., 10 ton ha-1 year-1 in the case of a mixed forest which consisted of sugar maple, American beech, and yellow birch in [33]).

Bottom Line: An increase in air temperature by 3 degrees C (5 degrees C) reduces cumulative net primary production by 21.3% (34.2%).However, the positive effects of CO2 enrichment (2 x CO2) outweigh the negative effects of warming (<5 degrees C).These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5 degrees C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biosphere Dynamics Research Group, Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan. todam@pop.lowtem.hokudai.ac.jp

ABSTRACT

Background: Changes in the timing of phenological events may cause the annual carbon budget of deciduous forests to change. Therefore, one should take such events into account when evaluating the effects of global warming on deciduous forests. In this article, we report on the results of numerical experiments done with a model that includes a phenological module simulating the timing of bud burst and other phenological events and estimating maximum leaf area index.

Results: This study suggests that the negative effects of warming on tree productivity (net primary production) outweigh the positive effects of a prolonged growing season. An increase in air temperature by 3 degrees C (5 degrees C) reduces cumulative net primary production by 21.3% (34.2%). Similarly, cumulative net ecosystem production (the difference between cumulative net primary production and heterotrophic respiration) decreases by 43.5% (64.5%) when temperatures are increased by 3 degrees C (5 degrees C). However, the positive effects of CO2 enrichment (2 x CO2) outweigh the negative effects of warming (<5 degrees C).

Conclusion: Although the model was calibrated and validated for a specific forest ecosystem, the implications of the study may be extrapolated to deciduous forests in cool-temperate zones. These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5 degrees C.

No MeSH data available.