Dynamics of a Neotropical Forest: The First Decade

尽管最近取得了进展，但其组成、结构和 物种丰富的热带森林的动态， 热带树木，仍然在很大程度上未知。 很少有长期研究 有大量的热带森林 足以进行个别树种的生活史分析，或 社区层面的分析。 这项研究将监测 命运（增长，生存和恢复）超过四分之一 数以百万计的树木被单独标记、绘制和识别， 在50公顷的永久性森林中有306种树苗和灌木 在巴拿马的巴罗科罗拉多岛的阴谋。 两次普查的情节 第一次是在1980年至1982年， 1985年第二次。 1990年的这一更新对以下方面特别重要： 有很多原因 在第一次人口普查期间， 巴拿马中部地区发生60多年不遇的干旱， 重死亡率在许多树种的阴谋，以及 物种相对丰度的变化。 没有任何一次类似的干旱 发生在这次普查期间。 因此， 评估重大突发事件对社区的影响， 气候事件对树木死亡率，生长， 和回收。 最近的调查还将揭示 每个物种的种群变化方向保持不变 在过去十年中保持一致。 它还将改善 分析树木生长和存活措施目前的业绩 每棵树的位置不仅取决于它当前的 生物和物理环境，但也作为其功能， 过去的业绩和最近的环境历史。 第一 时间，在何种程度上，个别树木的生长速度是 可以测试时间自相关。 根据一个 假设，只有增长最快的个体生存下来， 树冠 如果这是真的，那么树冠层的成年人可能 比平均和随机尺寸估计的年龄小- 人口的增长率通常是 金属 最后，但并非最不重要的是， 因为目前的地块数据，这是由一个相当大的 科学家们的说法已经不再准确。 基于 初步茎数，估计该地块已 已经经历了约10 - 12%的工厂总营业额， 直径大于1厘米。

In spite of recent progress, the composition, structure and dynamics of species-rich tropical forests, and the demography of tropical trees, remain largely unknown. Few long-term studies of such tropical forests exist that have population samples adequate for life history analyses of individual tree species, or for community-level analyses. This research will monitor the fate (growth, survival, and recuitement) of over a quarter of a million individuallly tagged, mapped, and identified trees, saplings, and shrubs of 306 species in a 50 ha permanent forest plot on Barro Colorado Island, Panama. Two censuses of the plot have been completed, the first between 1980 and 1982, and the second in 1985. This 1990 recensus is particularly important for a number of reasons. During the first census interval, the worst drought in more than 60 years occurred in central Panama, causing heavy mortality in many tree species in the plot as well as shifts in relative species abundance. No comparable drought has occurred during this census interval. Thus it will be possible to assess the community-level effects of a major episodic climatic event on longer-term patterns of tree mortality, growth, and recuitment. The recensus will also reveal whether the direction of population change for each species has remained consistent over the past decade. It will also enable an improved analyses of tree growth and survival measures current performance of each tree as a function of not only of its current local biotic and physical environment but also as a function of its past performance and recent environmental history. For the first time, the extent to which individual tree growth rates are temporally autocorrelated can be tested. According to one hypothesis, only the fastest growing individuals survive to reach the canopy. If this is true, then canopy adults may be much younger than ages estimated from averaged and randomized size- specific growth rates in the population--the usual projection metnods. Finally, but not least, the recensus results are needed because the present plot data, which are used by a sizeable number of scientists, are no longer accurate. Based on preliminary stem counts, it is estimated that the plot has already experienced about 10-12% total turnover in plants with diameters greater than one centimeter.