Keywords :
Gap; Growth of Seedlings; Indigenous Tree Species; Thinning; Two-storied Forest Management
บทคัดย่อ :
Against a background of a shortage of forest resources in tropical areas, this research project aimed to develop silvicultural techniques for indigenous trees on the Sakaerat Silvicultural Research Station in northeast Thailand. A two- storied forest management system was proposed, in which indigenous trees were planted under the canopy of fast-growing trees. Study plots were set up in June 2008 under two separate regimes (one-third and two-third thinning) that were applied to a 20-year-old Acacia mangium plantation and included control plots (unthinned) and gap plots. Seedlings of three indigenous tree species (Hopea odorata, H. ferrea and Xylia xylocarpa var. kerrii) were planted in every plot. The size of the seedlings (diameter at 30 cm above the ground and tree height) was measured every two months from July 2007 to July 2008. Hemispherical photographs were taken at each plot and the sky factor (canopy openness) was calculated. The survival rate of the seedlings was high (>90%) in every species and every treatment. For every species, both stem diameter and height increased as the sky factor (canopy openness) increased. H. odorata and X. xylocarpa var. kerrii were more sensitive to light conditions than H. ferrea, with both showing greater growth in the gap site than in the control plots. With respect to promoting the growth of the indigenous tree seedlings, gap planting was more effective than thinning method.
เอกสารอ้างอิง :
Sakai, A., Visaratana, T., & Vacharangkura, T. (2008) Effects of Thinning on Initial Growth of Indigenous Tree Seedlings in a 20-year-old Acacia mangium Willd. Plantation in Northeast Thailand. Proceedings of the FORTROP II: Tropical Forestry Change in a Changing World, 17-20 November 2008, Kasetsart University, Bangkok, Thailand.
