Study On Ecological Function Of Different Phyllostachys Edulis Stands In Northern Fujian Province

Moso bamboo (Phyllostachys edulis), which is most widely distributed in South China, has the largest amount and highest economic value among the bamboo species. It has not only high economic and social values, but also other important ecological functions, such as water and soil conservation. With large areas of hills and mountains, the Northern Fujian Province, is major region of P. edulis's distribution and cultivation. Because of extensive management of P. edulis plantations, the soil erosion, soil productivity maintenance and others ecological problems are very serious. Therefore, it is a important scientific issues that how to enhance the ecosystem service function in cultivating and utilizing P. edulis resources in high-effect and on a large scale. In this paper, the community structure and major ecological functions (biodiversity, soil property, water and soil conservation) of six types of forests—Evergreen broadleaved forest (CK_K), Cunninghamia lanceolata forest (CK_S), P. edulis pure foresty (T_ZC), eight P. edulis and two broad-leave tree mixed stands (T_ZK1), six P. edulis and four broad-leave tree mixed stands (T_ZK2()typles T_ZK1 and T_ZK2, the proportion of broad-leaved tree is about 20% and 40% respectively)and Mixed forest of C. lanceolata and P. edulis (T_ZS) were studied. The aims were to compare the difference of different P. edulis forests's compositive ecological functions, provide theoretical and technical guidances for P. edulis forest silvilcuture, controlling of water and soil loss and sustainable management in hilly area of Southern China, and also accumulate field experience for researching bamboo forestry's ecological functions. The main conclusions are as follows:(1) Stand vegetable research were carried by using community survey, and the results were that the plant species in those six stands were belong to 86 families, 166 generas and 231 species which included 80.40 percent families and 78.31 percent generas that were composed one or one to four species. Among them, there are 30 species of pteridophyte from 13 families and 21 genera, 2 species of gyrmnosperms from 2 families and 2 genera, and 199 species angiosperms from 71 families and 173 genera. There are 55 families, 90 generas and 118 species, 76 families, 128 generas and 156 species, 68 families, 120 generas and 148 species, 38 families, 54 generas and 60 species, 42 families, 57 generas and 64 species, 73 families, 109 generas and 129 species respectively in T_ZC, T_ZK1, T_ZK2, T_ZS, CK_S and CK_K stands.βdistribution model was better in fitting tree height, DBH and age distribution pattern.(2) Through bio-diversity analyzing, the number of communities species increased with the rate of broad-leaved species of plantation, and CK_K had abundant species(S), the highest Margalef richness index(R), Simpson index(D), Shannanon-Weiner index(H′), Pielou evenness index(E) and evenness-dominance-abundance index(Z), the lowest ecological dominance(λ) in the tree layer. In the shrub layer, the biggest S, R, D, H′and Z were in T_ZK1, the biggest E was in CK_K, and the biggestλwere in T_ZS and CK_S. In the herbaceous layer, T_ZK2 had the biggest S, R and Z, CK_K had the biggest D, H′and E, and CK_S had the biggestλ. On the community level, S and R were biggest in T_ZK1, the biggest D, H′and E were in CK_K, the biggest Z was in T_ZK2, and T_ZS had the biggestλ. The nonlinear relationship between bio-diversity indices and community biomass was not significant.(3) Soil property status had been studied through multiple parameters and several quantitative methods in all test stands. The soil physical properties analyzing showed that CK_K had the best soil physical properties, T_ZK1′s secondly, while, CK_S′s was worst. According to soil chemical properties research, CK_K soil had the best soil chemical properties, which was highest among nutrients contents in all stands. On the contrary, T_ZS′s chemical properties was worst, many of its soil nutrients were lest. The soil enzyme activity of T_ZK1 was the best, the max value of oil enzyme activity of six were in it stands, CK_S′s soil enzyme was worst because of soil enzyme activity value were worst. The percent of the Bacteria in microorganisms was more than 96.20%, so the rate of soil bacteria was higher than that of soil fungi and actinomycetes, and the number of soil fungi was lest. The magnitude of soil property comprehensive indexes of different test stands was CK_K>T_ZK1>T_ZC>T_ZK2>T_ZS>CK_S, this indicated that T_ZK1′s soil property was best in bamboo forestry. There existed highly significant or very significant negative relationship between the fractal dimension of soil micro-aggregates and many soil property indexes of soil physical and chemical properties, soil enzyme activity and soil microbiology quantity, and it is good for soil micro-aggregates fractal dimension in evaluating soil property, and the value of soil fractal dimension of different test stands was CK_KZK2ZK1ZCSZS.(4) The water-holding capacity of canopy,litter layer,and soil were further studied in all test stands,and the results showed interception by canopy (391.19mm) and the average canopy interception rate (17.33) of CK_K were highest, While, in bamboo forestry, T_ZS's interception by canopy(366.95mm) and its rate (16.26%) were much more than any other, the second in T_ZC foresty(335.71mm and 14.88%), the lest in T_ZK1 foresty(325.25mm and 14.41%), the interception by canopy and its rate were in very significant nolinear relationship with rainfall and throughfall respectively. The storages of different decomposed state and total forest litter are differed with stand, and the biggest storage of undecomposed litter, half-decomposed litter and decomposed litter were all in CK_S, by contraries, all of them were lest in T_ZC stands, and the second biggest of total litter storage in CK_K. The water-holding capacity of litter and its absorption rate changed not only with litter decomposed state, also with immersion time, and the curve regression model of them had been established. Soil water content decreased with the soil depth, and the maximum in CK_K followed by T_ZK1, and the minimum in CK_S, the their average soil water content of three layers (0²0cm, 20⁴0cm and 40⁶0cm) were 1125.67 t·hm-2, 1100.60 t·hm-2 and 1008.87 t·hm-2. In all, the water-holding capacity of forestry were highest (747.20mm) in CK_K, the second (696.53) in CK_S, the lest (641.17) in T_ZC, and in bamboo forestry, the biggest was T_ZS (683.26mm) followed by T_ZK1 (656.73mm).(5) Soil anti-erodibility of six stands showed that the content of organic matter, water stable index, soil structure coefficient, infiltration velocity, root weight, root length, and soil anti-scourability index decreased with the depth of soil, while, the damage rate of soil structure, aggregate degree, disperse rate and its coefficient increased with soil depth, indicating capability of soil anti-erosion decreased with the increase soil layer. The soil water stable index, anti-scourability index and the content of organic matter were in highly significant or very significant correlation with many soil physical and chemical properties indexes and soil biological activity indexes after Correlation Analysis and Principal component analysis, and they all had higher positive loading in the first principal component, so they can be used as a comprehensively quantitative index to evaluate the soil erosion resistance. The value of soil erosion resistance comprehensively quantitative index in different test stands was T_ZS>T_ZK2>T_ZK1>CK_K>CK_S>T_ZC, it indicated that bamboo forestry especially T_ZS, has better soil erosion resistance.(6) Comprehensive evaluation on six types of forests'main ecological functions showed that the decreasing order of it in different stands was CK_K>T_ZK1>T_ZK2>T_ZC>T_ZS>CK_S, this indicated that there is trend that forest ecosystem function enhanced with the increase of the rate of the broad-leaved tree, and P. edulis forestry especially T_ZK1, had better forest ecosystem function. So, increasing percent of broadleaved species can be used to guide improving P. edulis forestry ecological function in cultivating and managing P. edulis forestry.