海岸木麻黃海岸木麻黃林演替及人工更新技術之研究(3/4) Study on the plants succession and the artificial regeneration of the coastal Casuarina forests(3/4)

木麻黃是台灣海岸造林最重要的樹種，惟難以在現存林帶內天然下種更新，永續海岸林防風機能。成熟海岸木麻黃林分孔隙隨木麻黃上木枯死而逐年加大，即有其他海岸樹種自然入侵，形成樹種歧異度較高之混合林，唯此時期仍然有木麻黃上木存在，如果不經人為干擾，此些林分之自然演替會導向何處，以及是否會造成防風效能的減退等，皆有待深入探討。本計畫調查老齡木麻黃林及火災後之植群分佈，瞭解現有植生種類分布、下種更新條件及人工更新補助要領，可做為今後海岸木麻黃複層混合林之施業依據。Casuarina is the most important tree species at the coastal plantations in Taiwan. But the natural regeneration is hard to go into effect in the windbreak forest, which is unable sustain the windproof function of the coast forests. The gap size of the mature Casuarina forest was increased by the withered of the upper tree, then the other automatic tree species added into the pure Casuarina coast stands. Even high diversity of the mixed stands, if no any artificial disturbance, whether the windproof function will be reduced or not, and the plants succession will move towards where, which are need more data to prove it. This study is focused on vegetative distribution in the mature Casuarina plantations and the coast stands which were burned by forest fire, and clarify the species of present vegetation, the essential conditions of natural seedling regeneration and the main points of the artificial regeneration by the subsidization. That is the task to stand on the duplicate tree-crows with mixed species in the coastal Casuarina plantations.