Bamboo control of forest succession:: Guadua sarcocarpa in Southeastern Peru

Forest inventory data is presented as the basis for a conceptual model of bamboo-dominated forest successional dynamics in southwestern Amazonia. Forest succession is arrested in stands dominated by bamboo (Guadua sarcocarpa, Londo (n) over tildeo and Peterson) as demonstrated by data on tree size class distributions and seedling mortality. Mean percent mortality of tree seedlings (greater than or equal to 1 m height, < 1 cm dbh) was over twice as high in forest plots dominated by bamboo (B+) versus forest plots without bamboo (B-). Soil texture data did not correlate with distribution of bamboo-dominated forest stands; however, bamboo-dominated stands do appear to be associated with perched water tables. Canopy light penetration, as calculated from hemispherical photographs, was significantly higher in B+ plots as compared with B- plots; thus competition for light does not appear to explain arrested succession. Data on soil water content and stem damage to tree seedlings and saplings suggests that root competition and mechanical crushing by bamboo may cause arrested forest succession. Soil water content (0-10 cm) was significantly lower in B+ plots. On average, over four times as many seedlings and saplings were classified as having stem damage in B+ plots as compared with B- plots. Saplings of a given dbh were on average 29% taller in B- plots than those in B+ plots. We propose that the occurrence of bamboo-dominated forests can be explained by an interplay between mechanical properties of soils, wind disturbance, and elevated rates of tree mortality in the presence of bamboo. (C) 2002 Elsevier Science B.V. All rights reserved.