[Major features of decline of Pinus sylvestris var. mongolica plantation on sandy land].
[Major features of decline of Pinus sylvestris var. mongolica plantation on sandy land].
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发表时间：
2004-12
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通讯作者：
Xiangyun Wu;F. Jiang;Xiaodan Li;Yang Xue;S. Qiu
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作者：
Xiangyun Wu;F. Jiang;Xiaodan Li;Yang Xue;S. Qiu
针对辽宁张古台沙地蒙古针叶松人工固沙林的减少，研究了其减少的主要特征。衰落的蒙古松人工固沙林外观灰绿色，针叶极薄，开花结果率低，平均每棵球果数仅为10.4 ~ 16.5个，每千粒种子仅为6.96 ~ 7.39 g，空洞、涩味种子较多。2年生松针叶养分的季节动态相似，即N、P含量降低，K含量增加，表明养分循环不平衡。凋落林2年针叶叶绿素含量较高，健康林1年针叶叶绿素含量也较高，但增加幅度较大。松梢疫病的侵染危害是导致蒙古松人工固沙林衰败的最明显标志。森林退化后，松林高度和胸径明显下降，胸径分布结构“左移”。弱松数量增加15.9% ~ 27.2%，根系减少22.9% ~ 28.9%，其中吸收根（直径< 0.5 cm）减少最严重。
In view of the decline of man-made sand-fixation forest of Pinus sylvestris var. mongolica in Zhanggutai sand land of Liaoning Province, this paper studied the major characteristics of the decline. The appearance of the declining man-made sand-fixation forest of Pinus sylvestris var. mongolica was grey green, its needle leaf was very thin, the blooming and fruiting rate was low, the average quantity of cones per tree was only 10.4-16.5, with only 6.96 g to 7.39 g per thousand seeds, and there were many empty and astringent seeds. The seasonal dynamics of nutrients in 2-year-old pine needle leaf was similar, i.e., the N and P contents decreased, while K content increased, showing that the nutrient cycle was imbalance. The chlorophyll content in 2-year-old needle leaf of declined forest was high, while that in 1-year-old healthy forest was also high but with a wide increasing range. The infected harm of shoot blight was the clearest mark to the decline of man-made sand-fixation forest of Pinus sylvestris var. mongolica. After the forest declined, the height and the DBH of the pine trees decreased evidently, and the structure of DBH distribution moved "left". The quantity of weak pine trees increased by 15.9%-27.2%, the roots decreased by 22.9%-28.9%, and the absorbing roots (diameter < 0.5 cm) decreased most seriously.