Recruitment of lianas into logging gaps and the effects of pre-harvest climber cutting in a lowland forest in Cameroon

Abstract

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-yearold 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. #

Community Composition and Tree Population Structure in Undisturbed and Disturbed Tropical Semi-Evergreen Forest Stands of North-East India

“…Canopy-gaps, created by disturbances, and resulting spatial variability in under-storey light conditions have played a prominent role in expansion of forest diversity [7,53,57]. Such heterogeneities have been considered by many workers to be of fundamental importance in the maintenance and promotion of high tree diversity in tropical forest communities [2,14,28].…”

Nursery growth and rhizobia symbiosis of scandent Leguminosae species native to the Amazon region

“…Some studies have discussed the role of scandent legumes in regeneration in treefall gaps in forests (Grauel and Putz 2004;Schnitzer et al 2004). There is positive correlation between abundance and diversity of pioneer trees and scandent legumes (Schnitzer et al 2000), which may facilitate the process of ecological succession, and speed recovery from disturbances that occur within a forest.…”

Critérios para a amostragem de lianas: comparação e estimativa da abundância e biomassa de lianas no Cerrado

“…Consequentemente, os métodos propostos para a realização de censos e estimativa de biomassa de lianas apresentam diferenças em função da altura, de medidas de diâmetro, dos critérios de inclusão e da forma da parcela , o que dificulta e limita as comparações. Uma das variações metodológicas encontradas na literatura é o local de onde se toma a medida de diâmetro do caule das lianas , que pode variar desde o ponto mais largo até o longo do caule (DEWALT et al, 2000;BURNHAM, 2002), a 130 cm das raízes FARIAS, 2000;MASCARO et al, 2004;SCHNITZER et al, 2004;RICE et al, 2004;SENBETA et al, 2005;MADEIRA et al, 2009) a 20-30 cm das raízes ou próximo do solo (BURNHAM, 2004;GEHRING et al, 2004;GARRIDO-PÉREZ et al, 2008), a 130 cm do solo e a 150 cm do solo (MUTHUMPERUMAL; PARTHASARATHY, 2010). Em razão disso, Schnitzer et al (2006) apresentaram equação alométrica usando dados de diâmetro e biomassa desenvolvida a partir da análise de 424 indivíduos de lianas coletadas independentemente em cinco estudos realizados em florestas tropicais.…”