Research On Community Structure And Ecological Function With Different Thinning Intensities And Close To Nature Management Of Urban Artificial Forest

As one of the most important ecological forest of Shanghai, the overall quality of The Huangpu River water conservation forest directly related to the urban water system coastal protection and the construction and optimization of water-front landscape. In order to evaluate the overall function, explore the close to nature forestry management mode and improve the quality and sustainable development potential of the water conservation forest, this test investigated and analyzed the growing of stand、the undergrowth diversity、the habitat factors of undergrowth、air ion concentration、bacteria concentration of air under4different thinning intensities, which provide theoretical basis for forest ecosystem management. The results showed:(1) Thinning was benefit for the growth of the trees, the DBH、individual volume of different thinning intensities was slightly higher than the CK, while the effect on the height was not obvious. The first year after thinning, the growth rate of the DBH and individual volume on different stands was not obvious,but the second year after thinning was more than the CK respectively and did not show consistent rule.(2) The SLA of the control stand was the highest, the higher strengthening thinning had the higher SLA between the different thinning stands. The LDMC was T2>T1>T3>CK; the leaf N concentrations of Elaeocarpus sylvestris decreased as the strengthening of the tending, but the Cinnamomum camphor a was on the contrary; the leaf P content increased in the same trends generally as the N concentrations.(3) The species of the underground were increased as the strengthening of the tending generally, and the herbal was much more significant. The T2had the highest species richness. Pittosporum tobira and Distylium racemosum was the dominant species of regeneration layer, the second year after thinning the sun-loving plant occurred and increased dramatically. The dominant herbal was a little bit different between different stands. The diversity index of the woody plants of T2was the highest, and the hebal plants of the thinning stands was much higher the the CK, the H index was responsed the most significant. The species richness decreased because of the loss of the summer herbal species in2012.2.(4) After tending, the light transmission conditions for stand were improved, the temperature and the soil temperature increased, the relative air humidity decreased with the strength of thinning. The soil bulk was reduced, the soil total porosity and capillary porosity was slightly increased after thinning of0-10cm, the thinning has no effect on the10-20cm. Soil humidity salinity solid degrees had no obvious effect on the stand. The N concentrations、P content and the SOM of soil was slightly increased after thinning, besides the P content, the N of soil was generally increased as the strengthening of thinning, the N/P and C/N of soil had no obvious change after thinning. The soil of Elaeo carpus glabripetalus forest was slightly alkaline, and the Cinnamomum camphor a-Bischofia polycarpa mixed forest was slightly was slightly acidity.(5) The air anion in summer was much higher than the spring, the concentration of different stands had different patterns as the strengthening of the tending.3(T3) was the highest, and2(T2) was the lowest in summer, but2(T2) was the highest,4(T3) was the lowest in the spring of the Elaeocarpus sylvestris forests.5(T1) was the highest,7(T2) was the lowest in the summer, but8(CK) was the highest,6(T1) was the lowest of the Cinnamomum camphora-Bischofia polycarpa mixer forest. In total, besides the T3intensity with lower air anion concentration, the air anion had no significant correlation with the thinning intensities. The air bacteria of the stands was lower than the open space, the stands with highest RH had much more bacteria, but the concentration of different thinning stands had no obvious correlation as the thinning strengthening.In total, thinning was benefit for the growth of the trees, promoted the growth and regeneration of understory plants, and improved the function of water conservation and fertility status of soil to some extent, but didn’t show consistentrule in early period.