Document: AND-3-59-74

Field measurements of root respiration in sugar maple and red pine forests indicate no temperature acclimation.

BURTON, A.J.* and K.S.PREGITZER

Michigan Technological University, Houghton, MI 49931, USA ¹

Abstract:
Fine root respiration rates were measured in the field throughout the snow-free season for a sugar maple forest and a red pine plantation in Michigan. Respiration was determined for fine root samples (< 1 mm diameter) using an infrared gas analyzer configured in an open system. An aluminum cuvette base, buried in the soil to a depth of 18 cm, allowed the roots to be maintained at ambient soil temperature during respiration measurement. Objectives of the study were to determine the effects of soil temperature and soil moisture availability on respiration rates and to learn if respiratory Q₁₀ values previously determined in the laboratory were applicable to field conditions. Soil temperature and soil moisture were both important predictors of root respiration. These two factors explained 93% of the variation in root respiration observed among sample dates at the red pine plantation and 90% of the variation among sample dates at the sugar maple forest. Declines in root respiration associated with soil moisture deficits coincided with measured reductions in soil respiration at both sites. Root respiration rates measured in the field from April through November increased exponentially with temperature, with Q₁₀ values that were only slightly less than those determined for a temperature series in the laboratory (2.3 vs. 2.6 for sugar maple and 2.9 vs. 3.0 for red pine). These data suggest that little if any temperature acclimation occurs under field conditions for root respiration of these two species.

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This abstract is being presented at: 10:30 AM in session:
Poster Session #13: Decomposition and Soil Respiration.