Saproxylic beetles on aspen in commercial forests: a simulation approach to species richness.

摘要

European aspen (Populus tremula) is important in boreal forests because of its rich fauna and flora. In Finnish commercial forests, however, aspen stems, especially large ones, are rare. Alternatives to aspen in managed mixed (boreal) forests were studied with a decision-support system which included an ecological simulation model and a database on saproxylic beetles (and their habitat requirements); biodiversity was assessed according to the number of beetle species in the 3 forest management programmes compared. These were thinning from below with or without the retention of aspen (as green retention trees), and thinning 4 diameter classes by species (aspen, Norway spruce, Picea abies, and birch, Betula pendula and B. pubescens). The simulationresults showed that large aspen stems maintain the richness of beetle species in a forest. Such stems appear in commercial forests if green-retention trees remain after regeneration felling (thinning).