PARENT SESSION
Poster Session # 10: Soil Ecology.

Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Structural and functional restoration effects on soil microbial activity in two contrasting ecosystems.

Boerner, Ralph^*,1, Waldrop, Thomas², Brinkman, Jennifer¹, Callaham, Mac², ¹ Ohio State University, Columbus, OH, USA² U.S.D.A. Forest Service Southern Research Station, Clemson, SC, USA

ABSTRACT- As part of a national-scale evaluation of the consequences of structural and functional restoration treatments in ecosystems that historically had frequent fire, we determined the effects of reintroduction of dormant season fire (functional restoration) and thinning from below (structural restoration) on soil organic matter characteristics and microbial activity in South Carolina pine-oak and Ohio oak-hickory ecosystems. In South Carolina the three blocks in which treatments were imposed varied in age and size distribution whereas in Ohio they varied in parent material and site fertility. In the pine-oak ecosystem, fire resulted in reduced acid phosphatase and chitinase activity in the youngest block, but not in the older two. Thinning resulted in reduced chitinase activity in the oldest block. Phenol oxidase activity was reduced by both burning and thinning in the oldest block. Multiple regression indicated that posttreatment enzyme activity in this pine-dominated ecosystem was most closely linked to pretreatment soil carbon content and posttreatment soil C:N ratio. In the oak-hickory ecosystem, acid phosphatase activity was reduced by burning in all three blocks, whereas chitinase activity was unaffected. Phenol oxidase activity was increased by fire in the most fertile block. Thinning reduced acid phosphatase activity, but only in the least fertile block. Multiple regression indicated that posttreatment enzyme activity in the hardwood-dominated ecosystem was most closely linked to posttreatment soil carbon content, and to a lesser extent posttreatment soil C:N ratio, soil moisture, and soil texture. These preliminary results suggest that the consequences of restoration treatments on soil microbial activity may vary within and among ecosystem types in relation to their effects on the quality and quantity of soil organic matter.

Key words: microbial activity, restoration, soil, forests