A Study on some Symptoms of the Declining and Mortal Pinus massoniana Lamb. Forest on Nanshan Mountain in Chongqing
作 者 ：Liu Hou-tain, Zhang Wei-ping, Shen Ying-wa, Du Xiao-ming, Zou Xiao-yan, Liu Ruo-an, Ma Liang-qingo Du Shi-cai, Lan Kang-hou, Lou Ren, Lou Jia-ju and Tang Qin
Abstract:In 1982, some trees in a 1800 ha forest of masson pine on Nanshan Mountain. Chongqing,were found to be dying, since then, half of the trees have died off and the whole forest isin danger. On damaged trees, the needle became spotted blotch, dieback and even yellow at all, its internal tissue had been destroyed and early defoliated; the root system was undeveloped,and had few rootlets; the branch decreased and died; the growth of stem in height and diameter were weakened. It is showed that the plant has been growing unhealthily. It was alsoknown by the stem analysis that shows the phenomenon of growth weakening since 1967. The result of preliminary study suggests that the declining and dying of masson pineforest in Nanshan Mountain maybe related to environmental pollution.