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首页> 外文学位 >Stem mapping methodologies and analyses of stem density, plot size, sample size and spatial patterns of large trees in old-growth mixed-conifer and pine forests of the Sierra Nevada and Oregon.
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Stem mapping methodologies and analyses of stem density, plot size, sample size and spatial patterns of large trees in old-growth mixed-conifer and pine forests of the Sierra Nevada and Oregon.

机译：内华达山脉和俄勒冈州的老龄混交针叶林和松林中的大树的茎密度，样地大小，样本大小和空间格局的茎图绘制方法和分析。

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Large trees (>76.2 cm d.b.h.) at seven study sites (16—100 ha) were mapped using a GPS/laser rangefinder/digital compass system that has a measurable, sub-meter, error for any given point. Tree locations mapped with a tape and compass methodology were almost indistinguishable from the GPS maps at short distances, but required more time. Total survey station maps were compared to the GPS-based system and were more accurate at short distances (1 m) and in small plots than, but the total survey station is slower and its error in distance and azimuth can compound unpredictably over long distances and multiple set-up points if the survey grid cannot be reasonably closed in difficult forest conditions.; The actual mean large tree density at the study sites had a range of 8.7–27.3 stems/ha. Density of individual species peaked at 14.9 stems/ha for ponderosa pine, 11.3 stems/ha for Jeffrey pine, 8.2 stems/ha for incense cedar, 6.3 stems/ha for sugar pine, and 4.5 stems/ha for white fir. Both plot size (1000 m2, 4000 m2, or 10,000 m2 ) and the number of samples used (1–30 samples) were comparatively analyzed. In order to achieve a density estimate within one standard deviation of the mean, at least 17, 9 or 5 separate samples are required for plot sizes of 1000 m2, 4000 m2, or 10,000 m2, respectively. As the plot sizes increase, the mean and are median larger; the interquartile range is narrower; the maximum density is smaller and the minimum—zero—is the same.; Both fine-scaled (1 ha) and coarse (>10 ha) stem density and spatial patterns were detected at all study sites. Aggregated patch sizes exist at one, three and eight hectares when all species, study sites and size classes are considered together. The mean patch size of the smallest size class (76.2 –99.9 cm d.b.h.) is 1/5th hectare, while the largest size class (>125 cm d.b.h.) had mean patch sizes of fifteen hectares. On average, large Jeffrey pine trees are clumped at one, four and nine hectares; ponderosa pine at 1/2, two, five and ten hectares; sugar pine at one-quarter, one, five and nine hectares; incense cedar at 1/50th, four and twelve hectares; and white fir at one and a half, four and sixteen hectares.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirement: Microsoft Office.
机译：使用GPS /激光测距仪/数字罗盘系统对七个研究地点（16-100公顷）的大树（> 76.2 cm d.b.h.h.）进行绘制，该系统对于任何给定点都具有可测量的亚米误差。用磁带和罗盘方法绘制的树木位置在短距离上几乎无法与GPS地图区分开，但需要更多时间。将总测量站地图与基于GPS的系统进行了比较，并且在短距离（<1 m）和小地块中的精度更高，但是总测量站速度较慢，并且其距离和方位角的误差在长距离上可能会不可预测地复合如果在困难的森林条件下无法合理关闭调查网格，则需要多个设置点；研究地点的实际平均大树密度范围为8.7–27.3茎/公顷。美国黄松的单种密度最高为14.9茎/公顷，杰弗里松的最高密度为11.3茎/公顷，香柏木的密度为8.2茎/公顷，白松的最高为6.3茎/公顷。样区大小（1000 m 2 ，4000 m 2 或10,000 m 2 ）和使用的样本数（1–30个样本）进行了比较分析。为了在平均值的一个标准偏差内实现密度估计，对于1000 m 2 ，4000 m 2 或10,000 m 2 。随着地块大小的增加，均值和中位数会变大；四分位间距较窄；最大密度较小，最小值（零）相同。在所有研究地点均检测到细密（<1公顷）和粗略（> 10公顷）茎密度和空间格局。当将所有物种，研究地点和大小类别综合考虑时，总斑块大小分别位于一公顷，三公顷和八公顷。最小尺寸类别（76.2 – 99.9 cm d.b.h.）的平均斑块尺寸为1/5 公顷，而最大尺寸类别（> 125 cm d.b.h.）的平均斑块尺寸为十五公顷。平均而言，杰弗里（Jeffrey）大松树丛分为一，四和九公顷。在1 / 2、2、5和10公顷的美国黄松；四分之一，一，五和九公顷的木；第1/50 的香柏木，面积为4到12公顷；一棵半，四和十六公顷的白杉。*； *本论文是复合文件（作为论文的一部分，包含纸质副本和CD）。该CD需要满足以下系统要求：Microsoft Office。

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