| Understory in different stands of moso bamboo (Phyllostachys pubescens) and itsrelationship with the status of the soil nutrients have been conducted. The main researchesinclude: the correlation between the stand factors and diversity of understory; comparison ofthe understory between the mixed stands of bamboo-broadleaved /bamboo-coniferous andmanaged pure stands of moso bamboo; the impacts of the different management practices onthe growth of the understory; the relationship between the growth of the understory and the soilnutrients.DEN (the stand density) correlates evidently with the Dominant Index, Simpson DiversityIndex, and the Evenness Index of shrub and Species Richness of herb respectively. Mean DBHcorrelates prominently with dominant indexes, diversity indexes, evenness indexes, speciesrichness indexes of the understory and the number of the shrub species, the number of the herb,respectively,while the LAI (leaf index) and MLA (mean leaf angle) correlate weakly with thediversity of the understory.The linear regression equations were established to estimate thediversity indexes of the understory.The idea,using DEN, D, LAI, MLA and TD to predict thediversity of the shrub or herb, is right. The weak correlation between the understory biomassand stand factors reflects that the determinant of the development of understory was not onlythe stand factors but also the soil status and the microenvironment. It can't reflect the growth ofunderstory if only consider the stand factors.Because of the disturbance of the management, the quantitative characters of understorywere changed effectively, including the height, density frequency,dominance or coverage,important value (IV). The species content, the dominant species, the orders of the speciesimportant value, the species sequence, diversity of the shrub and herb and biomass of theunderstory were various effectively. For example, the species diversity,the evenness of theunderstory was decline in managed stand of moso bamboo. The management also enlarged theIV gap between the species, especially the shrub species. On the other hand, it declined theproportion of the shrub biomass and increase the herb biomass on the whole understoryaboveground biomass. The proportion of the shrub biomass are 95.8%, 57.8% and Less 30% inthe mixed stand of bamboo-broadleaved, bamboo-coniferous and managed stand of pure mosobamboo respectivelyDifferent management measures affect the grOwth of understory with. various degned.Both tending and soiI loosening theCt the sPecies contenL qUanitative characters and dominansPecies effectively BOth declined the diversity of the shrub and herb, biomass proPOrtion, andenlarged the gaP betWeen the dominan species and subdominan sPecies. The impaCt oftending tO shru diversity was evident than soil looSening; otherwise, itS impact tO herbdiversity was less evident than the latteL And the deCline amOUn Of the shrub biomassproPOrtion in Stand with tending was less than the stand with soil looseningChemical herbicide treatment has evident effectS on the understory The componentS ofsPecies, the quantitaive chotrs, the sPecies sequen9e of sbob and herb, the speciesdiversity and biomass have valled aller chemical herbicide treatInent. 5 years after treatmenLthe characters of understory in moso bamboo Stands are close to the tuds that have notreatment. It was indicated that the development of undbory was recoverable, if we adopt lessfrequenCy chemical herbicide treatment and keep the understory in the status of less diStUrbing.The development 0f the understoIy bidinall also shows the direction.The factor analysis on the stand factors and soil nutrition which thect the growth of theunderstory shows that the soil nutrition contribute more to the development of undeniory thanthe stand factors. And the understory is the good indicator of the soil nutrition status. Theuinderstory is favorable for increase the soil oguic matter and soil... |
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