Development of plantation techniques of dipterocarp trees for reforestation

本研究旨在寻找能在野外承受多种环境胁迫的双龙果树种属，并提出育苗育苗方法，以期利用该种属在热带亚洲草原或退化土地上进行环境再造林。根据在泰国那拉提瓦退化沙质土壤上的一个试验性种植地点进行的实地研究和实验室工作，得出以下结论：(1)利用各种环境传感器和数据记录仪在试验点的露天场地和马相思林分内的连续测量表明，马相思遮荫改善了幼苗的微环境；(2)光硬化，在苗圃种植前将遮荫的幼苗暴露在充足的阳光下，提高了6种龙果树属植物的幼苗成活率，分别是：龙果树（Dipterocarpus obtusifolius）、香果（Hopea odorata）、麻风树（Shorea lelesula）、刺梨树（S.roxburghii）、龙果树（S.roxburghii）。(3)从光合特性方面对6种金合欢的耐高温性进行了评价，考察了金合欢作为护理树候选树种的可能性；(4)在退化的沙质土壤上种植的油油树（Dipteocarpus obtusifolius）表现出良好的生长和良好的光合能力；(5)护理树的种植，在种植目标树种之前先种植耐应力树种作为护理树。提高了龙脑果苗的成活率

The present study was aimed at finding out dipterocarp species tolerating multiple environmental stresses in the field and at suggesting ways of nursing and planting seedlings, supposing to use the species for environmental reforestation of grasslands or degraded lands in tropical Asia. According to the field study at an experimental planting site established on degraded sandy soils in Narathiwat, Thailand and to laboratory works, the following findings were obtained : (1) Continuous measurements at open site and within an Acacia mangium stand established in the experimental site using a variety of environmental sensors and data loggers revealed that canopy shading by Acacia mangium ameliorated the microenvironment for seedlings, (2) Light hardening, exposing the shaded seedlings to full sunlight at nursery before planting, improved seedling survival of six dipterocarp species, Dipterocarpus obtusifolius, Hopea odorata, Shorea leprosula, S.roxburghii, Shorea sp., Neobalanocarpus heimii, (3) Possibility as an candidate for nurse tree was examined according to an evaluation of high temperature tolerance of six Acacia species in terms of photosynthetic characteristics, (4) Dipteocarpus obtusifolius showed good growth and excellent photosynthetic capacity when planted on degraded sandy soils, and (5) Nurse tree planting, planting stress-tolerant tree species as nurse tree in prior to planting the target species, improved the survival of dipterocarp seedlings