Carbon storage in forest soil of Finland. 1. Effect of thermoclimate
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- LISKI, J. & WESTMAN, J. Biogeochemistry (1997) 36: 239. doi:10.1023/A:1005711024022
A total of 30 coniferous forest sites representing two productivityclasses, forest types, were investigated on a temperature gradient(effective temperature sum using +5°C threshold 800–1300degree-days and annual mean temperature –0.6–+3.9°C) inFinland for studying the effect of thermoclimate on the soil C storage.Other soil forming factors were standardized within the forest types sothat the variation in the soil C density could be related to temperature.According to the applied regression model, the C density of the 0–1 mmineral soil layer increased 0.266 kg m–2 for every 100 degree-dayincrease in the temperature sum, and the layer contained 57% and28% more C under the warmest conditions of the gradient comparedto the coolest in the less and more productive forest type, respectively.Accordingly, this soil layer was estimated to contain 23 more C ina new equilibrium with a 4°C higher annual meantemperature in Finland. The C density of the organic layer was notassociated with temperature. Both soil layers contained more C at thesites of the more productive forest type, and the forest type explained36% and 70% of the variation in the C density of the organic and 0–1m layers, respectively. Within the forest types, the temperature sumaccounted for 33–41% of the variation in the 0–1 m layer. Theseresults suggest that site productivity is a cause for the large variation inthe soil C density within the boreal zone, and relating the soil C densityto site productivity and temperature would help to estimate the soil Creserves more accurately in the boreal zone.