Recruitment of lianas into logging gaps and the effects of pre-harvest climber cutting in a lowland forest in Cameroon
Schnitzer SA; Parren MPE; Bongers F
Forest Ecology and Management
The abundance of lianas (woody vines) and the detrimental impact that they have on tropical rain forest trees is widely recognized. Lianas are particularly abundant in disturbed areas of the forest such as logging gaps and pre-harvest liana cutting has been widely recommended throughout the tropics to reduce the impact of lianas during and following tree harvest. The effectiveness of forest-wide liana cutting however is currently unresolved particularly for reducing liana abundance in logging gaps. Furthermore our understanding of the dynamics and rate of liana colonization in gaps is limited. We tested: (1) the speed at which lianas recruit into logging gaps and their dynamics afterwards; and (2) whether pre-harvest liana cutting actually reduces the abundance of lianas in post-harvest logging gaps. To test hypothesis 1 we compared liana recruitment in new 1 and 6-year-old logging gaps. For hypothesis 2 we compared liana abundance and tree infestation by lianas in 1-year-old logging gaps in which all lianas had been cut 9 months prior to tree felling vs. 1-year old logging gaps in which lianas were not cut. Lianas recruited heavily into logging gaps within 1 year mostly by means of stem sprouts and many of these new stems were apparently able to persist for longer than 6 years. Lianas were significantly more abundant in the root/bole zone of gaps than in the canopy zone mostly due to the vigorous regeneration of stem sprouts. Canopy openness was highest in gaps one year after logging possibly due to the smothering effect of the lianas on developing trees. Although liana abundance increased significantly over the 6-year gap chronosequence direct liana infestation of trees remained the same. Pre-logging liana cutting however significantly reduced the number of lianas and also the number of liana-infested trees in logging gaps. Consequently liana cutting appears to be an effective method to reduce the abundance of lianas and thus minimize their detrimental effects on regenerating trees in logging gaps.