藏东南高山松种群结构及动态特征

ttttt目的ttttt构树林是南京城市近郊次生林的重要类型之一，是构成城市森林的重要组成部分。为了更好地了解构树种群结构与动态，以期为城市森林资源管理与建设提供科学参考依据。ttttttttttttt方法ttttt利用群落学研究的方法，在典型地段设置20个10 m×10 m的样方；结合种群年龄结构、高度结构、冠幅结构、生命表、存活曲线、时间序列预测等手段，对南京仙林地区的构树种群进行了详细的分析。ttttttttttttt结果ttttt(1)构树种群年龄结构呈近金字塔形，其低龄级具有较为丰富的种群数量；中龄级是种群构架的主体部分。(2)构树种群的高生长与直径生长具有显著相关性，其方程表达式为y=0.597 1+3.412 9lnx；受物种本身生物学特性的限制，构树种群高度以10 m以下居多。(3)构树的冠幅以10 m²以下居多，且与种群的高度和直径不存在显著相关性。(4)静态生命表显示，II级和VI级具有较高的死亡率和致死率，这是环境与种群生物学特性相互作用的结果。(5)种群存活曲线表现为Deevey-II至Deevey-III型的过渡类型。(6)种群时间序列预测表明，在理想状态下该种群仍能够较好地维持现状。(7)种群结构动态指数在有干扰和无干扰情况下分别为0.493和0.003，尤其是在具有干扰的情况下偏离0的程度低，说明种群还是具有潜在衰退的可能。tttttttttttttttttt结论ttttt该种群在短期内仍属于稳定的状态，但种群在低龄级向中龄级过渡的过程中存在着一定的风险，因此低龄级种群数量是保持群落结构稳定的关键。tttt

Spatial patterning and population structure of a common woodland herb, Trillium erectum, in primary and post-logging secondary forests

tttttPurposetttttBroussonetia papyrifera forest was one kind of secondary forests in the suburban of Nanjing, which is the main part of urban forest. The aim of this study is to know the structure and dynamic of the population clearly, in order to provide some useful suggestions for the forest management and the urban construction.ttttttttttttttttttMethodtttttBased on the field investigation, setting 20 plots sized 10 m×10 m, the population of B. papyrifera was studied by the methods of age class structure, height class structure, crown class structure, life time, survival curve and time sequence prediction.ttttttttttttttttttResultttttt(1) The age structure of B. papyrifera population exhibited the shape of pyramid in general, which meant that the lower-age populations were more and the mid-age was the main part of the population frame. (2) There was significant correlation between height growth and diameter growth, and the related equation was y=0.597 1+3.412 9lnx. Restricted by the biological characteristics, most individuals of B. papyrifera were less than 10 m height. (3) Most of the crowns were less than 10 m², which was no significant correlation with the height and diameter. (4) Life time indicated that mortality and disappearance rate were high in the stage of II and VI, because it was confined by the environment and population characteristics. (5) The survival curve was a transitional type from Deevey-II to Deevey-III. (6) Ideally, the population would keep stable according to the time sequence. Under disturbance and not-disturbance, population dynamic index were 0.493 and 0.003 respectively, particularly deviating from 0 lightly, which existed the risks of recession potentially.ttttttttttttttttttConclusiontttttPopulation of B. papyrifera in the study area was still in stable condition in future, but the population was still in the risk of transitive stage from youth age to mid age. The youth was the most important part for keeping population stably.ttttttttt