Selection of dipterocarp species for enrichment planting in a secondary tropical rainforest

Abstract

The selection of species for enrichment planting that involves native species in a secondary lowland dipterocarps forest as one of the tropical rainforest types should be conducted to maintain the sustainable management of tropical rainforests. The research of species trial of dipterocarp species was planted under a randomized complete block design with four replications. The following parameters were examined: survival rate, diameter breast height (DBH), pilodyn penetration (PP), and stress wave velocity (SWV). The survival rate (F = 1.72; p = 0.047), DBH (F = 6.67, p < 0.0001), and pilodyn penetration (F = 14.19; p < 0.001) significantly differed at 12.5 years after planting. The survival rate of Shorea leprosula was the highest (85%) of all the species, and the survival rate of other species, namely, S. macrophylla, S. ovalis, S. johorensis, S. scaberima, and S. parvifolia, was more than 70%. The best growth of DBH parameter was observed in S. platyclados. The DBH growth of S. platyclados 12.5 years after planting were 27.62 cm (mean annual diameter increment [MADI] = 2.2 cm/year). The species whose growth in DBH was similar to those of S. platyclados were S. leprosula, S. parvivolia, and S. ovalis. However, stress wave velocity (SWV) was not significantly different among dipterocarp species (F = 1.26; p = 0.234). Pilodyn penetration (PP) was significantly correlated with DBH (Pearson’s correlations = 0.306; p < 0.001), whereas stress wave velocity was not significantly correlated with DBH and PP (p > 0.05), and their Pearson’s correlations were 0.043 and −0.012, respectively. These results suggested that each dipterocarp species varied in terms of their growth and wood properties. Thus, choosing the species for enrichment planting in secondary tropical rainforests depends on the characteristics of each species and the desired final product of forest management.