Community Characteristics Of Quercus Liaotungensis Koidz. In The Lingkong Mountain In Shanxi Province, China

Quercus liaotungensis Koidz. forest is one of the typical vegetation types in deciduous broad-leaved forest regions in the warm temperate zone. It is a major component of forests and widely distributed in north China's Shanxi Province. We chose the community of Q. liaotungensis as our research object. Methods of quantitative vegetation analysis and biogeographic statistics were adopted. We studied the individual adaptation of Q. liaotungensis in different communities of typical areas, the population distribution pattern and community characteristics and trends, summarized its adaptation rule under ecosystem conditions of warm temperate zone and analyzed its inherent mechanism. Our study can offer some scientific references for protection and expansion of germplasm resources and sustainable management of Q. liaotungensis.There exist 182 seed plant species, belonging to 122 genera and 49 families in the Lingkong Mountain, accounting for 31.01%, 16.74% and 7.01% of the total species in Shanxi respectively and for 48.04%, 22.68% and 12.97% of the total in the Taiyue Mountain. Of all the seed plant species, gymnosperm shares four species, four genera of two families, while angiosperm has 178 species, 118 genera of 47 families. World-widely distributed families dominate the flora of the Lingkong Mountain, making up 42.86%. There are significant differences between the number of species and genera that each plant family includes. The distribution types of plant genera in the Q. liaotungensis communities follow an order TempG>TG>PG>ECHG. This well suggests that there are clear temperate characteristics in this area.From structural characteristics of different community types, it can be found that the community structures such as size-class structure and height structure of Q. liaotungensis were rather steady. However, we noted that there was an insufficient reserve of seedlings of Q. liaotungensis population. In the analysis of the community profile, phanerophytes occupied a dominant position in the community among all life form spectra of Q. liaotungensis. The leaves were composed mainly of papery and serrated single leaves. It can be concluded from the analysis of leaf properties and life forms that the phanerophytes with papery single leaves of microphylls and mesophylls in the Q. liaotungensis forest dominate the community profile, having typical features of deciduous broad-leaved forests in warm temperate zone.Analysis of variance (ANOVA) was used in the quantitative analysis on morphological traits of leaves of natural populations of Q. liaotungensis. The result showed that morphological traits of Q. liaotungensis on different parts in the tree differed significantly in eight indices, especially that the upper leaves differed remarkably from the meddle and lower leaves. Leaf morphological traits of different individuals in homologous populations also demonstrated obvious differences. In order to explore the forming mechanism, the law of population distribution and dynamic change of spatial distribution pattern of Q. liaotungensis populations, we analyzed the population pattern of Q. liaotungensis of different community types by combining the methods of fractal feature and judgment of distribution pattern. The result proved that the clumped distribution pattern was dominant in different community types, and the pure forest of Q. liaotungensis showed to be the maturest community type in this area. In addition, in order to expound the competition rule of the main tree species in the forest of Q. liaotungensis, we used niche theory, Lotka-Volterra competition equation and individual tree competition index model for quantitative analysis. The Q. liaotungensis populationwas in a dominant position altogether with Chinese pine, well exhibiting the typical forest community type in the temperate zone. According to prediction of the competition equation, Q. liaotungensis population gradually demonstrated its leading advantage in the pine-oak mixed forest with the development of the community. According to intraspecific and interspecific competition in the community of Q. liaotungensis, intraspecific competition is greater than interspecific competition in the Q. liaotungensis. It indicated that the effect of self-thinning on population dynamics was greater than that of alien-thinning.Q. liaotungensis can not only utilize seeds to breed but also has very strong sprouting ability from stumps. As the regeneration from seedling trees is difficult, the regeneration of Q. liaotungensis relies mainly on sprout regeneration. It can be found that structural characteristics of the Q. liaotungensis community remained similar to those in previous studies. Except for the high percentage of seedling individuals, bottleneck phenomenon can be found to occur in the medium diameter-class structure of Q. liaotungensis seedling tree population in the Lingkong Mountain. Because of the high survival rate and fast growth of seedling population, population quantity of Q. liaotungensis can break smoothly through "the bottleneck". Diameter classes keep relatively stable after "bottleneck", thus solving the problem of "the scarcity of seedling regeneration" in the regeneration of Q. liaotungensis. Sprouting regeneration regulation was analyzed with the indices of basal diameter and height of stumps, height, number and basal diameter of sprouts. The competition intensity among sprouting branches was quantitatively analyzed by the single tree competition index model.The species diversity of Q. liaotungensis in different communities and layers was measured by the methods of Shannon-Wiener index, Simpson index and Pielou evenness index. The result showed that the species diversity indices were different among communities, which resulted from the difference in development periods and the habitat conditions within community; the species diversity indices fluctuated among the different layers, and fluctuation range in shrub layers was larger than that in arbor layers. Q. liaotungensis pure forest was more stable than Q. liaotungensis-Juglans mandshurica community in Lingkong Mountain, which was deduced by analysis of species diversity indices in different communities and layers.Through our investigation on gap disturbance, the formation features of Q. liaotungensis, the impact of gap size and gap age on species diversity and the changes of community characteristics inside and outside gap were analyzed. The result showed that the gap formation was mainly because of the pest damage and the gaps were mainly caused by the fallen Q. liaotungensis or Populus davidiana trees. Most of the gap areas were about 25-50 m2, and the age of gaps less than five years had the highest proportion and those gaps were mainly formed by fallen trees with diameter of 12-16 cm. The gap sizehad greater impact on species diversity of seedlings, shrubs and herbages. Species diversity increased with the enlargement of gap area , generally, and influenced by gap age. Species diversity gradually declined as the gap age increased. In addition, the species composition and diversity were obvious different between inside and outside gap. The number of species inside gaps was significantly larger than that of outside gap.