Opinion Paper: Forest management and biodiversity

摘要

In this opinion paper we investigate the effects of forest management onanimal and plant biodiversity by comparing protected areas with intensivelyand extensively managed forests in Germany and in Romania. We want to knowthe extent to which differences in diversity of Romanian compared to Germanforests are based on management.The number of tree species was not different in protected and managed forestsranging between 1.8 and 2.6 species per plot in Germany and 1.3 and 4.0 inRomania. Also herbaceous species were independent of management, rangingbetween 13 species per plot in protected forests of Romania and 38 speciesper plot in German coniferous forest. Coarse woody debris was generally low,also in protected forests (14 to 39 m3 ha?1). The main differencebetween Romania and Germany was the volume of standing dead trees (9 to28 m3 ha?1 for Romania), which resulted in larger numbers of forestrelict saproxylic beetles independent of management. Large predators (wolves,bears and lynxes) are only found in regions with low human intervention.Thus, we identified a "cut and leave" type of management in Romania, inwhich clear-felling of forest are followed by long periods of no humanintervention. Forests managed in the "cut and leave" mode contained thehighest diversity, due to a natural succession of plant species and due tohabitat continuity for animals. In Germany intensive management eliminatespoorly formed tree individual and species of low market value during standdevelopment. Forest protection does not ensure the maintenance of more lightdemanding key species of earlier stages of succession unless competition byshade-tolerant competitors is reduced through disturbances.We compare the economics of intensive and extensive management. The "cut andleave" mode delivers less wood to the wood market, but saves expenses oftending, thinning and administration. Thus the net income could be quitesimilar to intensive management at a higher level of biodiversity.Our analysis suggests that forest protection per se does not yet ensure themaintenance of species. Clear-felling followed by natural succession may evenbe superior to the protection of old growth forests, regarding biodiversity.Further research is needed to substantiate this hypothesis.