Abstract:

Coniferous forests rarely occur in the tropics, but they play a unique role in maintaining biodiversity and habitat heterogeneity of tropical forest ecosystems. The Bawangling forest region (BFR) contains the largest tropical coniferous forest in China; this forest is dominated by Pinus latteri in the canopy layer and by a diverse variety of broadleaved species in the subcanopy and understory layers. Based on the relative dominance of the broadleaved species in the communities, we selected a “pure” stand and a mixed stand to analyze the spatial patterns and associations of the species in the canopy, subcanopy, and understory layers with a spatial point pattern analysis method. The results of the study were as follows: in the “pure” stand, the trees in the canopy layer showed aggregated patterns, whereas in the mixed stand, they showed aggregated patterns at smaller scales and random patterns at larger scales. In the “pure” stand, species in the subcanopy layer showed aggregated patterns at smaller scales and random patterns at larger scales, but they primarily showed aggregated patterns in the mixed stand. The trees in the understory layer showed random patterns in the “pure” stand and aggregated patterns in the mixed stand. With the increase in scale, the spatial associations between canopy and subcanopy species and between canopy and understory species changed from no association to positive associations in the “pure” stand. However, they changed from no association to negative associations in the mixed stand. The spatial associations between species in the subcanopy and understory layers were positive at all scales. These results indicate that the spatial patterns of broadleaved species are mainly controlled by the dominant conifers in the canopy layer in this natural tropical coniferous forest.

Key words: point pattern analysis, interspecific associations, tropical natural coniferous forest, mixed coniferous-broadleaved forest, Pinus latteri, Hainan Island