Acclimation of Russian forests to recent changes in climate

Area of Science:

• Ecology
• Forestry
• Climate Change Science

Background:

• Boreal forests are suggested to be carbon sinks, but carbon accumulation in living biomass is poorly understood.
• Estimates of carbon sinks in Russian forests vary, with remote sensing data suggesting larger sinks than forest inventories.
• Changes in allometric relationships within Russian forests over four decades are investigated.

Purpose of the Study:

• To analyze changes in allometric relationships among plant parts in Russian forests over the past four decades.
• To investigate the geographical variation in these changes and their correlation with climate variables.
• To assess the implications of these changes for the interpretation of remote sensing data and carbon sink estimations.

Main Methods:

• Analysis of a database comprising 3196 sample plots.
• Application of developed models to forest inventory data.
• Comparison of findings with experimental and mathematical models of tree responses to climate change.

Main Results:

• A continental-scale increase in the proportion of green parts (leaves and needles) in Russian forests was detected.
• Significant geographical variation exists, with the largest increase in European Russia (warmer, wetter) and a decrease in Siberian Northern Taiga (warmer, drier).
• Changes in carbon allocation align with predicted responses to increased temperature and soil drought.

Conclusions:

• Observed changes in tree allometry demonstrate potential acclimation to ongoing warming and altered water balance.
• The shift in the proportion of green parts may lead to systematic overestimation of living biomass carbon sinks by remote sensing methods.
• Further research is needed to refine carbon sink estimates and understand forest responses to climate change.