Malan Forest Liaodong Oak Forest Community Characteristics

Quercus wutaishanica Mayr.,belonging to the family of Fagaceae,is distributed in the western rolling country of liaotung peninsula,the western and northern upland of Hebei province, the southern upland of Heng mountain in Shanxi province,the Loess Plateau in Shaanxi and Gansu province,and Qinling mountain.Q.wutaishanica,which has significant value for environment,is a dominating species of the forest in the warm and temperate zone.Based on the theories and methods of Population,Community,Vegetation and Quantitative Ecology,we investigated the plots and analyzed the samples.Then,the date for researching the inter-specific affinity,species updating, and correlation between vegetation and environment were perfectly acquired.Therefore,making use of some software,the composition,structure,stability and future direction of Q.wutaishanica community in Malan forest region of Ziwuling Mountain on the Loess Plateau were analyzed via a lot of parameter.With an all-around investigation in Malan forest region,thirty plots of 10 m×10 m in eight typical quadrats were established.We surveyed the all arbor(higher than 1.3m),shrub(DBH, Diameter Breast Height,wider than 1cm),and seedling of Q.wutaishanica(shorter than 1.3m),and measured fifteen environmental indexes to describe the spatial position,terrain,and characters of soil.Utilizing the calculation of point correlation,Person's correlation coefficient(r),and the test ofχ~2,the inter-specific association of 69 woody plants was researched.Meanwhile,the correlation between the quantity of seedling and soil indexes,the comparisons of different types of fertility or exposure were analyzed by the means of Principal Components Analysis(PCA),hierarchical clustering method and one-factor Analysis of Variance(ANOVA).Finally,the distribution of shrub under the canopy was interpreted with environmental indexes via Canonical Correspondence Analysis(CCA).Now the results showed that:1.Variance Ratio(VR,=2.27＞1) analysis indicated that the overall association was significant positive.That is,along with the processing of community succession,the inter-specific relationship became positive and more species coexisted.The inter-specific association analysis of 69 woody plants(making up of 2346 pairs) showed that positive association against negative association was close to 4 to 6,whereas the point correlation coefficient was great(4.4 to 5.4),r correlation coefficient was little(3.6 to 6.4).The results of inter-specific association values suggested that they still competed against each other slightly(the relatively steady community could restrain it), without violent competition and resource scarcity.Theχ~2-test also showed that significant association was less than 10%.Therefore,we included that the inter-specific association of the climax forest community was infirm and showed an independent pattern.2.PCA of seedling showed that the separate variance of the four initial components were 44.09%,22.74%,13.07%,and 9.81%,while the cumulative variance of them was 89.71%.The first component greatly represented soil organic matter(SOM),total kjeldahl nitrogen(TKN), alkali-hydrolyzable nitrogen(Ne),humus thickness(H),and effective potassium(Ke).Meanwhile, the correlations between the components and environmental indexes,such as SOM,TKN,and Ne, were 0.941,0.913 and 0.809 accordingly and typically.However,the other three components generally represented defoliation thickness(D),pH,and effective phosphorus(Pe).3.Based upon the integrated fertility index which contained SOM,TKN,and Ne,the thirty plots were divided into three types.By reason of the correlations between them and seedling were significant(SOM:R=-0.418,P=0.022;TKN:R=-0.419,P=0.021;Ne:R=-0.442,P=0.014).Then ANOVA suggested that there were prominent difference between typeⅠand typeⅡ(P＜0.01),and so were typeⅡand typeⅢ(P＜0.05).The amount of typeⅡwas 213 seedlings more than typeⅠ, and 165 seedlings less than typeⅢ.So,the level of fertility was much important for the growth of seedlings.As for exposure,which had significant negative influence(R=-0.575,P=0.001), different types showed different amounts(more/less than 95 seedlings).From north to south,the seedling diversity reduced gradually.And there distributed almost no seedling in the right north and south.Surprisingly,the seedling was few in the southeast and southwest where the light was sufficient.Consequently,we figured that it was essential to evaluate the growth by the height and canopy.4.CCA was available to analyze the distribution of shrub because of various environmental indexes.The four axes revealed about 79.8%environmental information,while the two previous axes held probably 59.1%.The first ax(P＜0.01),which was observably correlated with elevation (Elev),slope(Slop),Ke,and crown density(CD),explained for 23.0%of the spatial distribution of shrub species.Because of the correlations between them(the first ax and Slop(0.828)＆Elev (0.806)) were great,we considered that the first ax revealed the variety of Slop and Elev.The second ax correlated with pH,SOM,and Ne likewise(P＜0.05).And also,the forth ax suggested the variety of SOM,TKN,and Ke.Therefore,we figured that Elev,Slop,Expo,Ke,CD,SOM,and TKN were important environmental factors,while pH,Ne,Pe,and SP were variational factors.The two-dimensional scatter plot of CCA ordination for plots showed that,along with the first ax(from left to right),the Elev and SP increased,the content of Ke and Pe,and CD decreased,and the Expo turned to north.Similarly,along with the first axis(from underside to upside),the scatter indicated that the SP,and pH increased,while the content of SOM,Ne,and TKN decreased.At last,we suggested that the distribution could not be determined just by a single environmental factor but codetermined at the same time.That is,to some extent,the Q.wutaishanica community is steady and mature as the climax forest community.