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Understory Diversity and Biomass of Polar-Birch Secondary Forest and Larch Plantation in Over-cutting Forest Area of Changbai Mountains

Author: HeLieYan
Tutor: KangXinGang
School: Beijing Forestry University
Course: Forest Management
Keywords: Understory vegetation Biomass model Diversity Birch secondary forest Larch plantation
CLC: S718.5
Type: Master's thesis
Year: 2011
Downloads: 188
Quote: 3
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Abstract

For this article Birch secondary forest and larch plantation index Gleason richness, Shannon index, Simpson index and Pielou index Birch different density of secondary forest and larch plantation species diversity in different ages, and compare differences in the two forest types, at the same time build a wider distribution of understory shrub layer 10 species the Canopy area Ac Canopy volume Vc, the square of the ground diameter and plant height product D2H arguments biomass model, and accordance with the form of shrubs arbor shrub (backbone obvious), the the typical shrub (more branches and the trunk is not obvious) to build a mixed-species model selected R2 larger, SEE smaller model as the optimal model and establish Model two forests, shrub and grass biomass and its allocation feature last Stand Factors and understory vegetation species diversity of understory vegetation biomass, the main conclusions are as follows: (1) two kinds of forest types have shown less than herbaceous understory shrub diversity diversity, but the diversity of understory vegetation differences in the two forests and different density or of different ages in the same forest type, the performance of secondary forest shrub diversity for Birch above the plantation, but the herbal diversity is lower than the larch plantation; canopy density of 0.8, the largest number of Birch secondary forest understory shrub species; canopy density of 0.6, the diversity and evenness of shrub most herb richness and diversity are highest; larch plantation after canopy closure shrubs, herbaceous species diversity increases with age. (2) shrub biomass model form of multi-cubic equation and the power function, the independent variables used in various optimal equation Vc and D2H arbor mixed shrub species model estimation accuracy is higher than the typical shrubs mixed species model, arbor shrub stem, root model estimation accuracy is higher than the leaves, branches model, typical shrubs dry sticks model than leaves, roots model. Most single-species organ the biomass model estimation accuracy than mixed species of Biomass model. (3) Birch secondary forest understory shrub herbaceous biomass of 7327.67 kg · hm-2, the larch plantations shrubs herbaceous biomass total 35863.17kg · hm-2, the two forests, understory biomass are shrubs main, but these two forests with different density and different stand age understory vegetation biomass quite different, Birch secondary forest stand density, shrub and grass biomass, stand density 0.8 to 1.0. minimum, shrub and grass biomass, canopy density 0.8, shrub biomass, and canopy density of 0.6, herbaceous biomass. Larch plantations, shrub and grass biomass increases with age increases, increased shrub biomass accounted for the proportion of the biomass of understory vegetation increases with age. (4) Birch secondary forest understory shrub mainly distributed in the dry, followed by the branches and roots, minimum for leaf the larch plantations shrubs biomass is mainly distributed in the dry, followed by root. Birch secondary forest understory shrub biomass composition dominant arbor shrub biomass mainly composed of shrubs in different ages larch plantations, mainly composed of the 39 years of of larch plantations shrub biomass Typical Shrubs pearl plum, Prunus species, of larch plantation for 52 years the largest species of shrub biomass contribution rate is spent Kai maple, followed Syringa reticulata arbor shrubs. Different densities Birch secondary forest shrubs, herbaceous aboveground part and underground part biomass allocation are manifested as shrub aboveground biomass is greater than the underground part of the biomass, herbal underground biomass greater than the above-ground biomass, while the larch Lin With increasing age, the aboveground biomass of understory vegetation gradually increasing the proportion of the total biomass of understory vegetation. (5) Birch secondary forest understory vegetation biomass is mainly affected by the impact of the canopy density, shrub biomass increased with increasing canopy density, but increases to a certain stage, when the stand canopy when (the canopy density = 1.0), shrub biomass but reduced herbaceous biomass decreased with increasing canopy density; larch plantation of shrubs, herbaceous biomass with stand age and per Hectare area increases. Birch secondary forest shrubs and herbaceous biomass diversity index value variation is not obvious, the larch plantation shrubs biomass as the diversity index value increases and decreases, while the herbaceous biomass with increasing diversity index values increases.

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