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Temperature Effects on Aspen Tree Inputs of Carbon and Nutrients to Soil
Reference
King, J.S., Pregitzer, K.S. and Zak, D.R. 1999. Clonal variation in above- and below-ground growth responses of Populus tremuloides Michaux: Influence of soil warming and nutrient availability. Plant and Soil 217: 119-130.

What was done
The authors grew four clones of aspen at two different temperatures (approximate 5C differential) and two levels of soil N-availability (high and low) for 98 days, while measuring photosynthesis, growth, biomass allocation, and root production and mortality.

What was learned
The higher of the two temperature regimes resulted in increased rates of photosynthesis (65%), more whole-plant growth (37%), and enhanced root production and turnover.

What it means
The authors conclude that "trembling aspen has the potential for substantially greater growth and root turnover under conditions of warmer soil at sites of both high and low N-availability." Furthermore, they say "an immediate consequence of this will be greater inputs of C and nutrients to forest soils due to greater rates of biomass production above- and belowground." In addition, they note that "higher rates of root production and mortality should substantially augment C delivery to forest soils and possibly result in greater nutrient availability." Consequently, we again can say, as we have previously said about many other situations, warmer is definitely better than colder, as the extra warmth stimulates a whole host of biological phenomena.