The Change By Growth And Structure, Plant Functional Group Of Woody Plant Of Daming Mountain Evergreen Broad-Leaved Forest After Frozen Disturbance

Freezing rain and snow disasters occur mainly in winter, which is a large-scale disturbance events. In recent years, in the background of global climate warming, to carry out the study about large-scale frozen interference on the south subtropical evergreen broad leaved forest species diversity and ecological processes affecting can provide a theoretical basis for evergreen broad-leaved forest biodiversity protection, conservation of plant species diversity and the sustainable management after the disturb.This research investigated the change by growth and structure, plant functional group of woody plants of Daming Mountain evergreen broad-leaved forest community after super frozen disturb in2008, the results showed that:(1) After frozen disturbance, Daming Mountain evergreen broadleaf forest community with the diameter enlargement, the size of the density of trees level changes margins, with DBH class increases, the density of trees is similar to "J" type distribution. Class Ⅰ population density changes over time has decreased first and then increased, Class Ⅱ, Ⅲ tree population density changes with time have increasing trend. Class Ⅳ, Ⅴ change over time all show increases and decreases, but the magnitude of fluctuations are small.(2)The Daming Mountain evergreen broadleaf forest community in2010populations of basal area growth rate is greater than2011’s. In2010, there are92species of basal area growth rate showed positive growth, accounted for81.42%;19species of basal area growth rate presents negative growth, accounted for16.81%;2species of basal area growth rate of growth, accounted for1.77%; in2011, there are68species of chest basal area growth rate showed positive growth, accounted for60.18%;45species of basal area growth rate presents negative growth, accounted for39.82%.(3)The species population growth rate is greater than30individual/year include Machilus pauhoi、Cinnamomum jensenianum、Diospyros morrisiana、 Engelhardia roxburghiana、Erythroxylum sinense、Macropanax rosthornii, in which the annual growth rate of Machilus pauhoi is88individual/year; the population of annual deaths were greater than5individual/year include Ampelopsis megalophylla、Stauntonia chinensis、Huodendron biaristatum, in which the average annual death individuals for Huodendron biaristatum is25individual/year.(4)The Darning Mountain evergreen broadleaf forest dominant population spatial distribution pattern was aggregated distribution, degree of aggregation is extremely obvious, but the extent of aggregation is different. Species’ Population aggregation degree strengthen are Huodendron biaristatum、Sabia limoniacea; species’ population aggregation degree from weak to strong are Acer fabri、Machilus pauhoi、Linder a metcalfiana、Elaeocarpus japonicus、 Diplospora fruticosa、Ficus heteromorpha; The degree of aggregation has been weakened are Litsea suberosa、Diospyros morrisiana、Macropanax rosthornii; aggregation degree from strong to weak is Eurya loquaiana.(5)After frozen disturbance, Daming Mountain evergreen broadleaf forest community3.2hm2plots of species richness is change year by year, the number of species has changed from big to small, the species number is reduced in2010but rebound in2011.(6)The change of important value is not obviously by the dominant species in communities after frozen interference, only shows some small fluctuations. Importance value maximum of the upper level is Huodendron Biaristatum, after the frozen disturbance its important value in reducing year by year in the first three years of recovery; the advantage of some species in the community is not large such as Machilus pauhoi、Lindera metcalfiana、Engelhardia roxburghiana、Castanopsis fabri、Rehderodendron kweichowense, mainly because of its existence of a large number of seedlings and saplings, its important value rise year by year.(7)After frozen disturbance, Daming Mountain evergreen broadleaf forest plant community species diversity index and evenness index changes little, species richness index change more obviously.(8)After frozen disturbance, Daming Mountain3.2hm2evergreen broadleaved forest, with diameter class increased, the individual number shows declining tendency, individual number or density of small level is the biggest, and then suddenly dropped sharply, and from one diameter to the larger diameter, the number of individual decrement ratio is larger, and the diameter is bigger, its change is not obvious. The number of individuals with diameter class distribution shows the "J". The community recovery in the first year, in2009, the number of individual maximum diameter is1diameter class, since2010,2011, diameter class of1individual number lower than in2009, and the diameter of2individual number is increased.(9)In2011, the average height of community of4.29m, a decline than the average height of6.00m of the community in2009.2009,2011annual Arbor community A (the height of more than25m), C (high≤10m) two layers of individual number proportion in the total individual number ratio are on the rise, but the C layer of the individual number decreased significantly, while B layer (10-25m height between) in individual numbers and percentages are obviously drop.(10)The total number of individual is720in2010, the death of the species number is97; The total number of individual is463in2011, the death of the species number is95.The survival curves shows that, Huodendron biaristatum、 Engelhardia roxburghiana close to the Deevey type Ⅰ, the death of the individual are larger individuals; Machilus pauhoi、Acer fabri、Litsea suberosa close to Deevey type Ⅲ, childhood mortality is higher.(11)According to the survey results, by calculating the important value, select30dominance species for DCA analysis, through4stand structure factor (basal area, frequency, number of individuals, the important value) as the basis, the Daming Mountain evergreen broadleaf forest community species divided into4categories functional group, their basal area, frequency, number of individuals, the important values change regularly with the type of life and its position in the community. Functional group of the species composition also change year after year.