Vine management for reduced-impact logging in eastern Amazonia

The presence of vines interconnecting the canopies of tropical forest trees has been thought to increase the damage to neighboring trees when a tree is felled during selective logging, resulting in larger canopy gaps and possibly prejudicing future timber harvests. To ameliorate this problem, vine cutting prior to logging has been recommended as a forest management tool. However, at present, little information exists on the economic and ecological impacts of vine cutting on tropical forest management. We undertook a study of vine management in a 210 ha forest stand. Our first objective was to determine vine species composition, stem densities, and the abilities of different vine species to resprout following cutting. Secondly, we assessed the degree of tree canopy connectedness due to vines and the amount of damage associated with felling trees with intercrown vine connections. Finally, we looked at the costs of vine cutting as a forest management tool. Vine density was found to differ among forest phases, being three times greater in young building phase forest than in mature forest. We encountered 63 species of vines in two (2 x 1400 m) transects and among the most common species, the degree of resprouting following cutting differed significantly. Typically, vines connected each tree to the crowns of from three to nine other trees. Felling trees with many vine connections resulted in canopy gaps that were twice as large as those created in the felling of vine-free trees. Although vine cutting prior to logging can reduce logging damage, it costs approximately $16 ha(-1), on average. This is equivalent to 8% of the profits of a typical logging-only operation in the region. Reductions in the cost of vine cutting could come with the development of species-specific cutting prescriptions that would reduce the total number of vine stems cut by focusing cutting efforts on aggressive species likely to cause silvicultural problems. (C) 1997 Published by Elsevier Science B.V.