Infodoc : Sciences, Techniques et Culture

In Sabah, Malaysia, logging operations leave substantial areas denuded of vegetation and topsoil. These sites are prone to erosion and slow to become reforested. Stands of pionneer trees established in these heavily disturbed sites may provide environmental conditions that foster recruitement of persistent forest species. results of a field experiment indicate that recruitment of pioneer trees in recently logged sites is limited more by site conditions than by availability of seeds. In lightly disturbed areas, where the canopy is open and soils are uncompacted, seed addition does not increase the density of pioneer tree seedlings; resprouting vegetation covers such gaps within 3 mo following logging. On landings and skid trails, pioneer seedling densities increase initially following [...]

In Sabah, Malaysia, logging operations leave substantial areas denuded of vegetation and topsoil. These sites are prone to erosion and slow to become reforested. Stands of pionneer trees established in these heavily disturbed sites may provide environmental conditions that foster recruitement of persistent forest species. results of a field experiment indicate that recruitment of pioneer trees in recently logged sites is limited more by site conditions than by availability of seeds. In lightly disturbed areas, where the canopy is open and soils are uncompacted, seed addition does not increase the density of pioneer tree seedlings; resprouting vegetation covers such gaps within 3 mo following logging. On landings and skid trails, pioneer seedling densities increase initially following seed addition but 12 mo after seeding, densities of pioneer seedlings are similar to those on unseeded areas. High seedling mortality in seed addition plots on skid trails and landings indicate that conditions on these compacted and nutrient poor sites during the first year after logging are unfavorable for the persistence of pioneer seedlings. On log landings, seedlings recruit adjacent to debris and bark fragments more frequently than expected by chance. Eighty percent of artificial seeds sown on landings and skid trails were washed away by overland water flow after three storms. The scattering of bark fragments and other small debris over denuded sites may assist seed capture and increase seedling survival temporarily, but many seelings die within a year. Improving harvesting practices to minimize the area scraped and compacted by heavy machinery will be more effective management than attempting to rehabilitate these areas following logging. The broadcasting of seeds of pioneer trees onto landings and skid trails immediately after logging may be a reasonable management option for hastening tree cover in denuded areas, but only if it is combined with site preparations that improve conditions for the survival of pioneer tree seedlings.