Spatial Distribution And Habitat Associations Of Trees In A Typical Mixed Broad-leaved Korean Pine(Pinus Koraiensis) Forest

The spatial pattern of a tree species is an important characteristic for a forest community as it provides critical information about the community structure, species coexistence, and resource use. We compared the population structure and spatial patterns of major tree species in a9hm2permanent sample plot typical mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains, China with the aim of gaining information supports a better understanding of the underlying ecological processes that controlled the development of the observed patterns. Tilia amurensis and Betula costata of live trees showed L-shaped DBH-class distributions. Abies nephrolepis presented partially normal shaped curve, dead and live trees of Pinus koraiensis presented J-shaped curve. The spatial pattern of live P. koraiensis and A. nephrolepis changed from a clustered distribution at small DBH-class to a random distribution at large DBH-class. There was a positive interaction between live P. koraiensis and other trees. When the scale was larger the individuals of their spatial association would be weakened greatly. An x2-test was used to test the influence of topography to the four major tree species. The result showed that the densities of four major live tree species showed no significantly affected by topography at small DBH-class and showed strong significantly affection at large DBH-class. Sapling of broadleaved species (Sapling I of B. costata and sapling II of T. amurensis) was strong significantly affected by forest canopy condition, and there were no signification on coniferous species under forest gap and closed canopy. These results suggest species differences in favourable canopy and forest floor condition. Differences in life history strategies and site preferences may explain the coexistence of these species.Use point pattern to study the spatial distribution of dead wood. The results showed that there existed greater differences in the densities of different age-class which followed the normal distribution, and the total dead wood density was368.8n-hm"2. Acer ukurunduense (27.8n·hm-2) and B. costata (26.1n·hm-2) were the major broad-leaved species while P. koraiensis (41.6n·hm-2) were the major coniferous species. The density of coniferous dead woods increased as increase of diameter at breast height (DBH) class, and followed J-shape within the scale of<150m. Patterns of total dead wood changed from clumped to uniform distribution with increase of scale. The different DBH groups clumped in different scales, the intensity of assemblage (IA) decreased with increasing DBH-class. The IA of different DBH-class increased with increase of scale. The pattern of different species and DBH-class showed differently, most of them showed clumped, while patterns of broad-leaved and coniferous DBH-class I were changed from random to clump as increase of scale. Dead wood with different existing form and decay class tended to clump distribution in the scale of<150m. We conclude that the spatial pattern of dead wood in this broad leaved-Korean pine forest resulted from long-term interactions between the communication and natural entironment; it also reflected mechanisms of natural regeneration.Understanding spatial distribution patterns of plants have great significance in explaining community assembles process. Ecologists found evidence which suggest the mean functional trait value of an assemblage changes predictably along environmental gradients. Functional traits directly indicate plants ecological strategies, and it is more predictable than species along a resource axes. Study the spatial pattern of functional traits is important to understand species co-existence mechanisms in a community. However, functional traits spatial distribution pattern and whether the same pattern of species existed in a temperate forest still unknown. Above all, leaf traits (leaf area (LA), specific leaf area (SLA) and leaf dry matter content (LDMC)) was studied in a9hm2plot Xiaoxin’an Mountain, Heilongjiang Province. The three traits could reflect different plant strategies directly instead of species and take spatial pattern analysis with these traits. Most of the individuals have big amount of small leaves and random distribution pattern, the individuals with big leaves aggreated in the study area. SLA and LDMC have similar distribution patterns; extremely small trait values have a random distribution pattern. The aggregation intensity was decresd with LDMC. Small leaves are generally belonging to evergreen species, they have enough ability to occupy in poor recouse supplied habitat and tolerance higher competitor among themselves that randmon distribution was found among this species. Big leaves species mostly belong to deciduous species which need more sunshine and fertilize, and they may aggreated grow up in gaps where may appear from typhone in summer. Individuals with high SLA usually means low settle ability probability of plant propagulum while with low SLA may means weak breed ability. Therefore, individuals with extremely small values are randomly distributed. Traits and their species usually have decoupled spatial distribution patterns which may explain traits’distribution is not only determinded by species characters.The distribution of tree species has attracted much attention for its significance in determining species performance and understanding the interactions between species and the environment. In old-growth forests, canopy gap dynamics and life-history traits can play important roles in the spatial distribution of species. In this study, we investigated the spatial distribution of coniferous and deciduous tree species in an old-growth temperate forest at high latitude, with a particular interest in evaluating the effect of gap dynamics on the spatial patterns and associations among species with different life-history traits. Our results showed that the abundance of coniferous species was negatively associated with canopy gap openness, while the abundance of deciduous species was positively associated with canopy gaps. Most of the species exhibited habitat preference caused by gap heterogeneity. For different tree height classes, most deciduous species showed significantly different spatial distributions before and after controlling for gap preference. The intensity of aggregation decreased or the aggregation became random when using a heterogeneous Poisson null model. Coniferous species did not show obvious trends. Significant positive associations were found between the deciduous species pairs; the associations were strong on a scale of<10m, which was consistent with the gap size distribution in the plot. The deciduous species aggregated within gaps at both juvenile and adult stages, while the coniferous species pairs showed no interaction under gaps. The coniferous and deciduous pairs were segregated within the gap sites. We concluded that differences in life-history strategies and site preferences may explain the coexistence of the species.Gaps disturbance is an important drive of the maintenance and the development of stand structure for mixed broadleaved-Korean pine forest. However, most research is limited to the overall change of the early and late seedlings establishment in gaps, they ignored the effects of gaps on seedlings emerged and then died during this period.915perennial seedling ((H)≥30cm, DBH<1cm) quadrats at4m2(2m×2m) were set up in a9hm2plot in a typical mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains. All seedlings in the quadrats were tagged, measured, and identified according to species. We studied the seedlings dynamics of recruitment, mortality and growth rate, discussed the process of seedlings establishing in gaps and shaded understory based on censuses in2006,2008,2010and2012. We found42seedlings species in the plot, gaps significantly promoted the establishment of11seedlings species. The density of regeneration of Prunus padus, B. costata, Ulmus laciniata, Aralia elata, Sorbaria sorbifolia, Maackia amurensis and Picea koraiensis seedlings increased significantly in canopy gaps compared with shaded understory, while P. padus, U. laciniata, A. elata, S. sorbifolia and M. amurensis seedlings showed higher mortality in canopy gaps than shaded understory. Gaps also significantly promoted the growth of A. nephrolepis, U. japonic a, Picea koraiensis, Sorbus pohuashanensis and M. amurensis seedlings. There were31seedlings species emerged in2008and then died in2010and2012, the density of the5species were changed drastically in gaps. Fraxinus mandshurica was one of the seedling species emerged in2010and then died in2012and the only species changed drastically in gaps. It is also discovered that topography and biotic factors as well as canopy gaps combined effected the establishment of seedlings in mixed broadleaved-Korean pine forest.