Respiration Rates in the Forest Floor of Birch and Aspen Stands in Interior Alaska

Van Cleve, Keith; Sprague, Diane

This paper presents data on the influence of physical and chemical properties of the forest floor, and moisture and temperature on respiration rates in birch and aspen forest floors in central Alaskan Boreal forests. Physical and chemical properties of birch and aspen forest floors did not differ sufficiently to cause significant differences in forest floor respiration between the two vegetation types. Minimum forest floor moisture contents of 20 to 50% in aspen and 20 to 70% in birch produced marked decreases in forest floor respiration rates. This effect was greatest at 1 and 5°C where respiration dropped to zero. During periods of adequate moisture litter respiration rates were approximately 5 to 10 times greater at 20°C than at 1°C. Maximum average respiration rates during the experimental period, obtained at 30°C, were approximately 0.05, 0.20, and > 0.30 g CO2m-2hr-1 for aspen L, F, and H layers, respectively, and 0.06, 0.21, and > 0.30 g CO2m-2h-1 for birch L, F, and H layers, respectively. Multiple regression analysis showed that temperature is 2 to 5 times more important than moisture in explaining variability in respiration data. For both litter types the respiration rate on a per gram basis of the L layer > F layer > H layer. However, when the volume weight of each litter layer is considered, the respiration rate of the H layer > F layer > L layer.

Respiration Rates in the Forest Floor of Birch and Aspen Stands in Interior Alaska

Series