Effect of nurse tree species on early growth of Anisoptera marginata Korth. (Dipterocarpaceae) on an Imperata cylindrica (L.) Beauv. grassland site in South Kalimantan, Indonesia.

摘要

The effect of 4 nurse tree species on early growth of the indigenous dipterocarp species Anisoptera marginata, was studied on an Imperata cylindrica dominated grassland site in South Kalimantan. A rationale for the study was that fast-growing nursetree species can ameliorate site conditions in such a way that dipterocarps, which are not able to tolerate open grassland conditions, can be integrated into fast-growing tree plantations. The trial was established with a randomized complete block (RCB)design with 4 replications under a 3-yr-old species trial testing suitable species for Imperata grassland reforestation. At the age of 19 months, the survival rate of A. marginata was 83-98%, with no statistically significant differences between the nurse tree species. Wild boars caused 68% of the total mortality. Height and diameter (D0.05) increments were highest under Paraserianthes falcataria (140.3 cm and 12.5 mm), and differed significantly from those under Acacia crassicarpa (90.0 cm and 8.4 mm),A. mangium (57.7 cm and 5.5 mm) and Gmelina arborea (19.2 cm and 3.5 mm). This can be explained by the higher levels of photosynthetic photon flux density (PPFD) penetrated to the understorey of P. falcataria stands (38-84% PPFD) than the other stands (<30% PPFD). Height and diameter (D0.05) increment of Anisoptera marginata increased until 40-50% PPFD. Results indicate good prospects for the diversification of fast-growing plantations on Imperata grasslands using dipterocarps with wide ecological tolerance, and stress the importance of the relationship between the nurse tree species and the understorey light conditions for the growth of underplanted dipterocarps.