Intercropping Short Rotation Timber Species with Teak: Enabling Smallholder Silviculture Practices

Community forest management for timber production requires short- and long-rotation companion species to fulfill the demands of the timber industry, improve farmer welfare and maintain environmental sustainability. Four species (Falcataria moluccana, Neolamarckia cadamba, Acacia mangium and Gmelina arborea) were tested as short-rotation timber crop companion species for teak (Tectona grandis) on dry-rocky soil in the Gunungkidul community forest. The selection of short-rotation timber species was based on growth performance and survival rate at the teak site. Two years after planting, the viability of G. arborea (87.3%) and A. mangium (78.2%) was significantly (p < 0.05) higher than that of N. cadamba (40.6%) and F. moluccana (18.0%). G. arborea and N. cadamba achieved the best growth in terms of height, diameter, basal area, and volume, with the growth of A. mangium and F. moluccana being significantly inferior. Gmelina arborea has the ability to adapt to teak sites, grow well, and accompany teak. Neolamarckia cadamba demonstrated good growth with potential as a teak companion, and it demonstrated limited drought tolerance on the dry-rocky soils of the study sites. Acacia mangium had a high survival but produced slow growth, indicating that it required an advance evaluation in future years. Falcataria moluccana has different growing site requirements to teak so the performance was relatively poor at the study site. This mixed pattern provides benefits to farmers through commercial thinning of short rotations species, 5–8 years post establishment. Thinning operations will also increase the productivity of residual teak stands. The diversification of timber species in community forests can provide earlier returns, enabling the adoption of silviculture management by smallholders and communities.