Higuchi P, Silva A C, Louzada J N C, Machado E L M
Departamento de Engenharia Florestal, Universidade do Estado de Santa Catarina, Lages, SC, Brazil.
Braz J Biol. 2010 May;70(2):271-7. doi: 10.1590/s1519-69842010000200006.
The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance from the propagules source, the higher the tree density and the lower the mean tree height. The population showed different spatial distribution patterns according to the spatial scale and diameter class considered. While small trees tended to be aggregated up to around 80 m, the largest individuals were randomly distributed in the area. A plausible explanation for observed patterns might be limited seed rain and intra-population competition.
本研究的目的是评估繁殖体来源的影响以及树木大小等级对生长在桉树人工林冠层下的巴西木瓣树个体空间格局的影响。为此，在巴西东南部拉夫拉斯市一片3.16公顷的桉属和伞房桉属人工林的林下，对所有土壤高度处直径（dsh）>1厘米的巴西木瓣树个体进行了绘图。附近最大的巴西木瓣树成熟个体被视为繁殖体来源。采用线性回归评估繁殖体来源距离对种群参数（密度、断面积和高度）的影响。通过Ripley K函数评估树木的空间格局。总体格局表明，繁殖体来源距离对树木的空间分布有很大影响，主要是对小树，这表明离繁殖体来源越近，树木密度越高，平均树高越低。根据所考虑的空间尺度和直径等级，种群呈现出不同的空间分布格局。小树在80米左右的范围内倾向于聚集，而最大的个体在该区域内随机分布。对观察到的格局的一个合理的解释可能是种子雨有限和种群内竞争。
