Acacia mangium, a nurse tree candidate for reforestation on degraded sandy soils in the Malay Peninsula

Abstract

We investigated the suitability of Acacia mangium Willd., a fast-growing tropical leguminous tree, as a nurse tree for reforestation with indigenous species on severely degraded sandy soils in southern Thailand. Planting A. mangium yielded a survival rate of 91% and satisfactory growth (7.7 m height, 56 mm dbh, 59 Mg dry weight ha-1 aboveground biomass) 45 months after planting, indicating the species' suitability for reforestation. Three dipterocarp species (Dipterocarpus alatus Roxb. ex G. Don, Hopea odorata Roxb., and Shorea roxburghii G. Don.) planted simultaneously with A. mangium showed better growth than when planted alone. Seedlings of all three dipterocarp species that survived transplanting showed better survival when planted with A. mangium. The findings suggest A. mangium is an effective nurse tree for dipterocarp seedlings. The carbon and nitrogen contents of surface soil did not increase in the A. mangium stands. Microclimate measurements showed moderated air temperature, relative humidity, and soil temperature in the mixed planting. The moderated microclimate under the A. mangium canopy is thought to be responsible for the improved growth of the dipterocarp seedlings. If dipterocarp seedlings are planted after A. mangium grows enough to provide shade, initial survival rates should improve. Copyright © 2005 by the Society of American Foresters.