Effect of liana cutting on tree regeneration in a liana forest in Amazonian Bolivia

Lianas, woody climbing plants, are a conspicuous component of tropical fore st canopies that might affect prevailing conditions in the forest floor and thus impact tree seedling regeneration. The effects of lianas on tree seed ling survival, growth, and density were studied in a lowland liana forest i n Bolivia. Gravimetric soil water content and canopy openness were measured to evaluate whether these factors changed as a result of liana cutting. I established 24 square plots of 900 m(2) each, and after an initial set of m easurements, all lianas were cut in half of them, while the others plots we re used as controls. Tree seedling growth and survival of two tree species were evaluated: Clarisia ilicifolia and Astronium fraxinifolium. Eighteen m onths after liana cutting, seedlings in liana-cut plots grew significantly taller and produced more leaves than did seedlings in control plots, but su rvival was not affected by treatment. Seedling growth following liana cutti ng was significantly higher in A. fraxinifolium than in C. ilicifolia seedl ings. Densities of tree and liana seedlings did not change after liana cutt ing. Gravimetric sail water content was apparently not affected by liana-cu t treatment. Canopy openness increased significantly in liana-cut plots, bu t only by 4%, and only after 26 mo. I conclude that lianas hinder the growt h of tree species seedlings differentially, which in turn might shift the b alance in competitive interactions between seedlings. Thus, at the study si te lianas could affect tree regeneration.