山翠池地區玉山圓柏林空間分布

Spatial patterns of Juniperus morrisonicola Hayata forest at the Cuei-Chih area in Mt. Syue

本研究針對雪山翠池地區之玉山圓柏林，進行空間分布調查研究。設置1個100m×100m之永久樣區，計算並統計小樣區內不同株數的頻度分布，以下列5種空間分布指數檢測族群空間分布之型態及強度：變異數／均值比率（I）、負二項參數（k）、聚集指數（IC）、塊集指數（C）及Cassie指標（CA）；並以TSTRAT的林分分層標準，將1ha永久樣區內之玉山圓柏，加以分層。分析結果顯示：玉山圓柏全林分屬於聚集分布。玉山圓柏林以TSTRAT分層模式界定之林分不同發育階段共計分為9層，再將1ha永久樣區劃分不同面積級與9個樹冠層級，進行交叉運算，由上述不同空間分布指標的分析結果顯示，玉山圓柏在不同尺度及不同森林層次上之空間分布均為聚集分布。由聚集強度發現，林分不同發育階段，除了第9層多屬於被壓木，呈現不正常之倒伏現象外，其餘8個森林層次中，第1～4層之林分發育各階段，結構屬較為穩定型態，而第5～8層則顯示幼苗時期林分仍處於相互競爭階段，林分結構較不穩定。

The research investigated the spatial patterns of Juniperus morrisonicola Hayata at the Cuei-Chih Area. A permanent plot of 100 m×100 m was established to examine the numbers of different individual. K-parameter of negative binomial distribution (k), Index of clumping (IC), Index of patchiness (C) and Cassie’s index (CA) were used to analyze the patterns and strength of the spatial distribution. The results revealed aggregative distribution spreading pattern for J. morrisonicola Hayata of all area within different scales and different forest layers. The canopy layers of J. morrisonicola Hayata analyzed with the TSTRAT　Model showed 9 layers. Layer 1 to 4 were sorted by growing steps with stable forest structures. Layers 5 to 8 were in the seedling and juvenile stage under competition and the structures of forests were unstable. The　ninth layer were composed of suppressed woods and most of them were lodging abnormally.