Enrichment Planting to Supplement Natural Regeneration of Valuable Timber Resources and African Blackwood in a Community-Managed Forest of Tanzanian Miombo Woodland

Abstract

African Blackwood (Dalbergia melanoxylon), locally known as Mpingo in Swahili, is a tree species of critical importance in Tanzania, particularly for crafting woodwind instruments such as clarinets and oboes. However, its natural population is declining due to the imbalance between its slow growth rate and high industrial demand for timber. While natural regeneration remains essential for sustaining this species, planting offers a strategic method to supplement resources. Enrichment planting in forest gaps presents a promising approach to integrating conservation with community-based forestry. This study aimed to develop an enrichment planting method to supplement the natural regeneration of African Blackwood (ABW) in local forests. A 1.5-ha permanent plot was established in a community forest, and 1, 503 nursery-raised seedlings (aged over six months) were transplanted at a spacing of 2 m × 2 m. Growth and survival were monitored over five years. Results showed a survival rate of approximately 62% after five years, with a maximum seedling height of 320 cm. The observed survival and growth performance were moderate compared to other Dalbergia species' enrichment planting experiments in monoculture plantations. Growth performance varied spatially, with significant correlations between seedling growth and environmental factors such as soil pH and vegetation structure. These findings demonstrate that enrichment planting holds the potential for sustainable ABW resource conservation in natural forests. Although further long-term monitoring is necessary to evaluate its effectiveness fully, this approach offers a viable strategy for enhancing tree resources and biodiversity in community-managed forests while supporting local development and conservation goals.