Impacts of logging on the regeneration of lowland dipterocarp forest in Indonesia

Research into the impacts of logging on the regeneration of lowland dipterocarp forests has been carried out in Central Kalimantan (Indonesian Borneo) as part of the UK Department for International Development funded Indonesian Tropical Forest Management Programme. The paper describes the impact of logging on the radiation environment, dipterocarp seedling growth and mycorrhizal dynamics and assesses the impact of logging on the forest as managed under the Indonesian Selective Cutting and Replanting system (TPTI). The study concludes that soil disturbance associated with the logging operation is the main factor limiting seedling establishment and regeneration. The creation of skid trails is associated with removal of the upper soil layers and the pool of shade-suppressed dipterocarp seedlings. The distance to seed sources limits establishment of new seedlings in large gaps following logging. In relation to improving sustainable management of dipterocarp forests, it is suggested that great care should be taken to apply reduced impact logging techniques to protect the soil and dipterocarp seedlings and mycorrhizal fungi. Logging systems can be modified to maximise the regrowth rate of dipterocarp species while inhibiting that of less valuable pioneer species by limiting the size of individual canopy gaps formed by logging so that their projected ground area does not exceed 650 m. This implies felling no more than two trees per gap.