Spatial Point Pattern Analysis on Typical Mixed Forest Fallen Wood in the Forest of Inner Mongolian Greater Khingan Mountains

Relying on the Ecological Station of Inner Mongolian Greater Khingan Mountains,this paper studied different tree species and different tree diameter fallen wood distribution patterns in three typical mixed forests including Larix gmelinii-Betula platyphylla mixed forest,Populus davidiana-Betula platyphylla mixed forest and Betula platyphylla-Larix gmelinii mixed forest through the method of point pattern analysis.The results show that:(1)the fallen wood distribution pattern in both Larix gmelinii-Betula platyphylla mixed forest and Betula platyphylla-Larix gmelinii mixed forest present an aggregated distribution.While in the Populusdavidiana-Betula platyphylla mixed forest,it presents a random distribution.(2)the Larix gmelinii fallen wood in three typical mixed forests tends to be a random distribution,while the Betula platyphyllafallen wood and Populus davidianafallen wood are mainly with aggregated distribution.The Betula platyphylla and the Larix gmelinii in Betula platyphylla-Larix gmelinii mixed forest exist a large scale of competition in the 1-23 mscale and they have no significant distribution relationship.The Populus davidiana and the Betula platyphylla have a strong competition between each other in the 1-7mscale,while it has no significant distribution relationship in the large scale.(3)the distribution patterns of differenttree diameter fallen wood in three mixed forest are different.Large diameter tree is mainly with random distribution.Both the small and medium-sized diameter tree species present an aggregated distribution.The large scale diameter fallen wood and the small and medium-sized diameter fallen wood have a strong competition in small scale,as well as the medium-sized diameter fallen wood and small scale diameter fallen wood.