Synergy Mechanism Between Soil And Vegetation Of Key Ecological Public Welfare Forest In Changsha

The ecological public welfare forest plays an important role in maintaining and improving human living environment, ecological balance, as well as species protection. With the improvement of the construction of Changsha-Zhuzhou-Xiangtan urban agglomeration, how to protect the forest resource and how to plan the public welfare forest around has become the hot point item. In order to improve the ecological environment quality, protect the forest resource, improve the investment climate and resident environment, realize the goal to build ecological Changsha city, Changsha city has launched the construction of ecological public welfare forest. Research of the soil and vegetation synergy mechanism in ecological public welfare forest area,we can understand the quality of the ecological public welfare forest resources, structural distribution and growth momentum, and also we can know how soil properties effect ecological public welfare forest distribution, it will help to advance the construction of forest ecological system in Changsha. It can provide guidance to optimize the public welfare forest community structure, improve the ecological public welfare forest quality and promote public welfare forest ecological function as well.In this paper, we look the key ecological public welfare forest as the research object, set up 11 pieces of standard sample, and measure 24 soil properties parameter values and 6 vegetation characteristic index value in sample area. According to the soil properties parameter values, use the principal component analysis to evaluate the soil fertility quality, explore the correlation degree between vegetation characteristics and soil properties through the grey correlation method, combined with the coupling model to study the synergy degree between the two parts finally, the main results are as follows:（1）From the aspect of species diversity, the diversity of three different type forests in the public ecological welfare forest is different. The Simpson index and the Shannon-wiener index have the same trend:pine and fir forest>pine forest> Chinese fir forest; but the trend of the Pielou index is the pine and fir forest （0.772）>the pine forest （0.739）>the fir forest （0.693）. The Simpson index and Shannon-Wiener index of the shrub layer is greater than the herb layer and the tree layer in three different type forest. The Simpson index and Shannon-Wiener index of the herb layer is lower than that in the pine and fir mixed forest, but bigger than that in pine forest and fir forest.（2） Pecies biomass in different layer is not alike under three different type forests in the key ecological welfare forest in Changsha. The trend is pin-fir forest(1418 g·^-2)<fir forest(1612.43 g·m^-2)<pine forest(2380.96g·m^-2).But the species biomass trend in the tree layer is pine-fir mixed forest>fir forest>pine forest, the reduce amplitude from pine and fir mixed forest to the pine forest is 26.23%;While the species biomass trend in shrub layer is in contrast to the trees layer, the growth amplitude from pine-fir mixed to the pine forest is 87.20%;The species biomass in herb layer is consistent with that in shrub layer, that is pine forest(1346.97 g · m^-2)>fir forest(485.98 g · m^-2)>pine-fir mixed forest(99.88 g · m^-2).（3） Forest stock volume trend of the key ecological welfare forest in Changsha is pine-fir mixed forest (60.28 m³ · hm^-2)>the fir forest (56.71 m³ ·hm^-2)>the pine forest (51.76 m³ · hm^-2), but the change amplitude is small, the total variable coefficient is 7.61%.（4）Different soil indicators in three type forest have different size. As a whole, the trend of the soil fertility quality is the pine-fir mixed forest （0.274）>the fir forest （0.135）>the pine forest （-0.499）; In particular, the trend of which is the pine-fir mixed forest< Chinese fir forest< the pine forest is the capillary porosity and soil clay; the trend of which is the pine-fir mixed forest>the fir forest>the pine forest is soil bulk density, coarse silt soil, soil powder grain, total phosphorus, total potassium, effective phosphorus and potassium.（5）The soil of the key ecological welfare forest in Changsha is conducive to the development of vegetation community, the correlation between the them is greater than 0.6, the particular trend is the pine forest （0.680）>the fir forest（0.651）>the pine-fir mixed forest（0.649）.（6） Coordination stability between different vegetation and soil properties is slightly different. The coordination between plant Simpson index and the soil is relatively stable under different type forest, the overall variation coefficient is the smallest （1.02%）. The overall variation coefficient of the coordination between the plant volume and the soil is 4.52%. And the coordination between plant Pielou index and the soil properties is the lowest, the total variation coefficient is 8.17%.（7） The coordination between different soil properties and the plant characteristics is different in different type forest. The dominant factor of the pine and fir mixed forest is the soil physical property, the coupling value is 0.713, the synergistic effect of the soil chemical properties is the lowest（0.634）.The dominant factor of the broad-leaved forest is the soil chemistry properties（0.668）,the synergistic effect between the soil biological properties and the plants is the worst（0.615）. The dominant factor of the coniferous forest is the soil biological properties （0.687）, the synergistic effect between the soil chemistry properties and the plants is the worst （0.623）.