Effects of harvest intensity on the marketable organ yield, growth and reproduction of non-timber forest products(NTFPs): implication for conservation and sustainable utilization of NTFPs

Background: Non-timber forest products(NTFPs) are an important part of forest biodiversity, and the subsistence and trade of local people, especially in less developed countries. Because of the high ecological and economic value, NTFPs have faced the problem of over-exploitation, and the key to solve this problem is to determine the feasible way of sustainable utilization of NTFPs. Harvest intensity is one of the most important and easily controlled utilization factors, which can greatly influence the plant individual survival, growth and reproductive performances,and even the population structure and dynamics. Therefore, we chose two common and important NTFPs species with different marketable parts(i.e., Acanthopanax senticosus with tender leaves and Aralia elata with tender buds)as our study objects. Aiming to determine the optimum harvest intensity for sustainably utilizing both NTFPs species, five levels of harvest intensity treatments(i.e., control, light, medium, high and severe) were designed to assess the effects of harvest intensity on their marketable organ yield, plant growth and reproductive performances.Results: The biomass growth rates of marketable organ and plant growth of A. senticosus under light harvest intensity treatment were significantly higher than those under other harvest intensities. The plant height growth and 1000-seed weight of A. elata under severe harvest intensity treatment were significantly lower than those under control treatment.Conclusions: The light harvest intensity with 25% leaf removal and the high harvest intensity with all terminal buds harvested are the optimum harvest intensity to maintain the sustainable utilization of A. senticosus and A. elata,respectively. These findings could provide managers with basic but practical guidance for making decisions about the sustainable harvest management plan for the cultivated NTFPs species, and further provide a theoretical basis for managers to establish the harvest regulations for wild NTFPs species. Consequently, the local residents or communities can improve their income while ensure the sustainable development of wild NTFPs.