国外松衰退病原因的研究

对安徽省国外松大面积衰退和枯死原因的调查研究表明，造成这种衰退和枯死的现象是多方面因素共同作用的结果，是一种林木衰退病，该衰退病的发生原因：1）诱发因素：温度年较差较大、年降雨量分布不均镁、土壤粘重板结或容重过大、地势低汪积水、土壤瘠薄、林分密度过大；2）激化因素：干旱严重重复发生、割脂过早过度、霜冻、食叶害虫等害虫危害；松针褐斑病等病害侵害；3）促进因素：松枯梢病菌、根腐病菌、立木腐配病菌、天牛、小蠹虫等害虫危害。

Causal factors of decline disease in exotic pine (Pinus taeda and P. elliottii) plantations.

Investigation on the cause of the decline of exotic pine plantations in Anhui Province was carried out from 1995 to 2000. The results showed that the cause might develop from the interaction of three or more sets of factors. The first group of factors called as predisposing factors were high and low temperature and rainfall, poor soil fertility,and excessive soil bulk density, soil moisture, and of stand density;the second group of factors called as inciting factors were insect defoliators, damaging diseases of needles, late spring frost,severe drought,and excessive resin tapping,and the third group of factors called as contributing factors were several biotic agents such as shoot blight infected by Sphaeropsis sapinea, decay wood and root rot by fungi, and bark beetles and wood borers.