Effects of Temperature and Moisture on Carbon Dioxide Evolution in a Mixed Deciduous Forest Floor

Abstract

Rates of CO2 evolution from forest litter and soil reflect the metabolic activity of the biota, including live roots and organisms responsible for decomposition. The objective of this study was to quantify the relationship of temperature and moisture to forest floor CO2 evolution in a mixed deciduous forest with the expectation of using this relationship to predict temporal changes in CO2 evolution rates in this and other similar forest ecosystems. Mean daily total CO2 evolution, measured via the inverted box method and infrared gas analysis, exhibited a significantly strong relationship with mean daily litter temperature (R = 0.94). Measured rates (3924 g CO2 m 2 year ) were < 3% higher than those predicted from a regression equation with litter temperature as the independent variable. Litter respiration rates measured with a differential respirometer at field temperatures were equivalent to 838 g of CO2 m 2 year. These values were subtracted from total CO2 efflux measurements for an estimate of 3086 g of CO2 m 2 year 1 evolved from the soil (including roots). This rate was within 1% of the 3095 g m 2 year 1 predicted from mean daily litter temperatures. Estimates based on litter temperatures overestimate CO2 evolution under extreme moisture conditions throughout the year and underestimate in early fall, when litter respiration is high—due in part to increased amounts of readily available energy and nutrients from freshly fallen leaves. Additional Index Words: forest soil respiration, forest litter respiration, oxygen uptake. View complete article To view this complete article, insert Disc 3 then click button8