- 期刊
琉球松線蟲受害材性質之研究
Study on the Properties of Nematode Infested Pinus luchuensis
摘要
本省松樹線蟲萎凋病為害之蔓延，受多方囑目，而為林業上之一重要課題，若欲執行整治，勢必涉及受害林木之處理，本簡報提出重要之受害木材料分析結果供參考。松樹林木於為害後，木材之含水率降低許多，但仍然維持在纖維飽和點以上，由伐採原木之斷面，立即可見是青變，隨伴者亦常見鑽木昆蟲之通道及幼蟲，微生物亦會隨這些通道向木材內部逐漸叢生。進行熱鹼溶液溶解度之測試，證實其隱藏之木材腐朽菌存在可能性亦大增，在不同期限為害木材之熱鹼溶解度隨之增高。松材線蟲為害產生之木材對衝擊抵抗力急速衰退，在為害木之半年期限內即有發生，同樣的在試材上之劣化現象，亦顯示在木材靜曲強度之結果中，使得松木材質之變異性增加。
並列摘要
The pine trees with known times of kill by nematode infestation were sampled and some of the wood properties were studied. The moisture content of the wood in the standing nematode-killed tree decreased significantly when compared to that of a living tree. A difference in moisture content with increasing height and depth from bark in the bole was noted. The test results showed that the moisture content of wood remained near or above fiber saturation point and the heartwood tended to hold slightly higher moisture content than the sapwood after one year of kill. The warm and humidity environment in northern Taiwan and the resulting high moisture content of the wood caused a fast rate of fungaI activities in the wood. The observations of the sample bolt cross sections demonstrated that blue stain fungi prevailed in the wood. Some blue stains penetrated deeply into the heartwood and covered entire cross section of the trunk. The results of increased solubility in one percent hot sodium hydroxide solution indicated that the existence of rot in association with the blue stain. Changes in wood properties as a result of nematode-kill were indicated by the results of the toughness tests on living and nematode-killed wood. The mean toughness dropped within half of the year after the kill. The drop in mean toughness continued with time after kill. The progressive deterioration of nematode-killed wood was shown by static bending properties. The modulus of elasticity of the wood was reduced more than the modulus of rupture. In general, the variations in the tested results of various wood properties increased with time since kill.