Secondary Forest Regeneration Under Fast-Growing Forest Plantations on Degraded Imperata cylindrica Grasslands

BACKGROUND

In Southeast Asia, large areas of former rain forest lands are covered by fire-climax Imperata cyclindrica (alang-alang) grass. Grass has potential to colonize varying types and sizes of land preventing regrowth of woody species. Natural forest recovery is inhibited by fires and competition with grass and shrubs. Planting fast growing tree species can create needed micro-climate and speed up regeneration of woody species.  This study compared the regeneration of native tree species under the canopy of tree plantations, riverine areas, and uncultivated grassland areas.

research goals & methods

The study is conducted in the Riam Kiwa plantation area in South Kalimantan, Indonesia. This area has a distinct dry season and deeply weathered, acidic soils, and is considered good for forest plantations.  A Finland-Indonesia Forestry Program established restoration trials covering about 1,000ha. This study sampled 16 stands and inventoried tree species and site characteristics to understand regeneration dynamics under different ground vegetation conditions. 

conclusions & takeaways

The study finds  that commericial plantations could be used to facilitate forest restoration with native trees. However, understory would be damaged during the harvesting operation and with fast-growing species in the canopy, it is unclear if the understory trees would be established enough to survive post-harvest. The  strategy could be used in areas where reforestation is important not just for timber but other interventions such as biodiversity conservation, protected area restoration and riparian zone recovery.