The Structure And Spatial Pattern Of Dominant Wood Populations In Secondary Forest In The Northeastern China

Wood populations, as major components, play an important role in forest community dynamics. Populations have a set of attributes that, to a large degree, can reflect role and function of populations, occurrence and variation of inter-specific relationship. We can predict future population dynamics based on the attributes, such as structure, density, age-class and spatial distribution patterns. Understanding the characteristic and spatial patterns of population, especially underlying mechanism, is very important in both ecological theory and forest management.Secondary forest, the most important forest resources in China, from secondary succession following a disturbance that removed the previous forest, was likely very different from previous forest at many aspects, such as population structure, composition, productivity, spatial patterns and ecological functions. We examined structure , age, basal area, stock, and spatial patterns of dominant wood species in secondary forest of the northeastern China.There were 6 dominant wood populations, Betula platyphylla, Fraxinus mandshurica, Acer mono, and others (Phellodendron amurense, Populus davidiana, and Quercus mongolica), the proportions of each species were: 2:2:5:1 by stem number and 4:3:2:1 by basal area, respectively. The curve of age distribution showed that there was slightly positively skewed for total stand age. The dominant age class of Fraxinus mandshurica, with obvious spatial distribution patches, was between 50-70, and of Betula platyphyll and Acer mono, with complicated patch structure, was 40-60 and 30-50, respectivelyThe basal area distributions of dominant wood species were also positively skewed. The spatial distribution patches of basal area with both higher value and lower value exhibited at smaller scales, and with medium value exhibited at relatively larger scales. There was marked gradient variation of patches for Fraxinus mandshurica, and many small patches for Betula platyphylla, and no clearly patches for Acer mono and others wood species. These differences of patterns may reflect difference of developing potential.There were significant stock different among wood species, with decreased in the order of average individual stock: Populus davidiana {Po)>Fraxinus mandshurica (Fr)>Betula platyphylla (Be)>Phellodendron amurense (Ph)>Quercus mongolica (Qu)>Acer mono (Ac). The proportions of total stock of wood species, for (Be):(Fr):(Ac):(Po):(Ph):(Qu), were 0.39:0.35:0.18:0.05:0.03:0.01.The significant positively correlation (R2=0.3212-0.6682) between age and stock indicated that there will a great increase of stock with stand developing.The stem density, in spite of uniform distributed, according to statistics analysis result, was still exhibited spatial clumped patches at certain scales based on kriging maps.