ORGANIC-MATTER DECOMPOSITION FOLLOWING HARVESTING AND SITE PREPARATION OF A FORESTED WETLAND

Organic matter accumulation is an important process that affects ecosy stem function in many northern wetlands. The cotton strip assay (CSA) was used to measure the effect of harvesting and two different site pr eparation treatments, bedding and trenching, on organic matter decompo sition in a forested wetland. A Latin square experimental design was u sed to determine the effect of harvesting, site preparation, and relat ive position within the wetland on organic matter decomposition at soi l depths of 5, 10, and 20 cm. Repeated measures analysis of variance w as used to test for treatment effects on organic matter decomposition, soil temperature, and soil oxidation depth. Cellulose decomposition i ncreased at each soil depth as site disturbance increased, with beddin g > trenching > whole-tree harvest > reference. The cellulose decompos ition response was correlated with changes in soil temperature; the te mperature coefficient Q(10) equaled 6.0, which is greater than previou sly reported values. Position within the wetland relative to an adjoin ing river affected the decomposition and soil oxidation depth. Because the rate of decomposition is strongly controlled by temperature, high er rates of organic matter decay are expected to continue on harvested and regenerated sites until canopy closure reduces soil temperature.