Effect of liana cutting on tree regeneration in a liana forest in Amazonian Bolivia
Lianas, woody climbing plants, are a conspicuous component of tropical forest canopies that might affect prevailing conditions in the forest floor and thus impact tree seedling regeneration. The effects of lianas on tree seedling survival, growth, and density were studied in a lowland liana forest in 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 m2 each, and after an initial set of measurements, all lianas were cut in half of them, while the others plots were used as controls. Tree seedling growth and survival of two tree species were evaluated: Clarisia ilicifolia and Astronium fraxinifolium. Eighteen months after liana cutting, seedlings in liana-cut plots grew significantly taller and produced more leaves than did seedlings in control plots, but survival was not affected by treatment. Seedling growth following liana cutting was significantly higher in A. fraxinifolium than in C. ilicifolia seedlings. Densities of tree and liana seedlings did not change after liana cutting. Gravimetric soil water content was apparently not affected by liana-cut treatment. Canopy openness increased significantly in liana-cut plots, but only by 4%, and only after 26 mo. I conclude that lianas hinder the growth of tree species seedlings differentially, which in turn might shift the balance in competitive interactions between seedlings. Thus, at the study site lianas could affect tree regeneration.