Abstract
This paper describes differences in canopy arthropod community structure and herbivory between old-growth and regenerating coniferous forests at the H. J. Andrews Experimental Forest in western Oregon. Species diversity and functional diversity were much higher in canopies of old-growth trees compared with those of young trees. Aphid bio-mass in young stands was elevated an order of magnitude over biomass in old-growth stands. This study indicated a shift in the defoliator/sap-sucker ratio resulting from forest conversion, as have earlier studies at Coweeta Hydrologic Laboratory, North Carolina. These data indicated that the taxonomically distinct western coniferous and eastern deciduous forests show similar trends in functional organization of their canopy arthropod communities.