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Transcript of FAST-GROWING SPECIES PLANTATIONS – Myths ... › assets › midocs ›...




    May, 2004

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    Introduction.__________________________________________________________ 4

    Relevant Terminologies _________________________________________________ 5

    Plantation definitions: ______________________________________________________ 5

    Fast-growing species: ____________________________________________________________ 5

    Plantation:_____________________________________________________________________ 6

    Fast- wood plantations:___________________________________________________________ 6

    Biological Diversity in general:_______________________________________________ 6

    Species biodiversity measurement and indices: _________________________________ 7

    Alpha, beta and gamma diversity: __________________________________________________ 7

    Species Richness: _______________________________________________________________ 8

    The Diversity Index (H): _________________________________________________________ 8

    The concentration of dominance (Cd): _______________________________________________ 8

    Other indices and concepts: _________________________________________________ 9

    Importance Value Index (IVI): _____________________________________________________ 9

    The Niche concept:______________________________________________________________ 9

    Niche space partitioning and resource sharing: ________________________________________ 9

    Review methods on vegetation & species diversity analysis ____________________ 10

    Materials and Data analysis: _______________________________________________ 10

    Vegetation study and analysis: ______________________________________________ 10

    Density:______________________________________________________________________ 10

    Frequency: ___________________________________________________________________ 11

    Basal Areas: __________________________________________________________________ 11

    Measurement of Cover: _________________________________________________________ 11

    Importance Value Index (IVI): ____________________________________________________ 12

    Calculation of Diversity Indices: ____________________________________________ 12

    Shannon-Wiener Diversity (H): ___________________________________________________ 12

    Concentration of dominance (Cd): _________________________________________________ 13

    Hill’s numbers of N1 & N2: ______________________________________________________ 13

    Index of similarity (Sorensen’s Index- SI) (β- Diversity): _______________________________ 13

    Dominance- Diversity (D-D) curve: __________________________________________ 14

    Findings and discussions_______________________________________________ 14

    Plantations: History and Development:_______________________________________ 14

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    Plantations and the argumentation of their environmental issues:_________________ 16

    Plantations and Biodiversity: _____________________________________________________ 16

    Water Matters: ________________________________________________________________ 18

    Plantations and the Soil: _________________________________________________________ 20

    Plantations and Pests: ___________________________________________________________ 21

    Genetically Modified Trees: Opportunity or Threat? ___________________________________ 22

    Plantations and Global Warming:__________________________________________________ 22

    Fast-growing plantations: possibility to achieve species diversity on degraded lands? 23

    IVI, distribution and species diversity indices of ground flora species under Teak, Acacia and Eu.23

    Dominance Diversity (D-D) curves:________________________________________________ 29

    Effect of seasonal and plantation age aspects on species diversity indices of ground flora: _____ 30

    Effect of tree density on growth development and composition ground flora species: _________ 31

    Conclusions _________________________________________________________ 33

    References: __________________________________________________________ 34

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    AAABBBSSSTTTRRRAAACCCTTT::: Plantation is neither inherently good nor inherently bad. It is a neutral technology which, when

    poorly planned and executed, can cause grave problems; and when well done, can deliver not just large quantities of wood, but a range of environmental and social benefits. Obviously, If, plantations replace natural forest, or take over lands previously used by farmers, they might be considered a bad thing. If, on the other hand, they are sensitively sited on degraded lands and managed by local communities, the opposite will hold true (Cossalter and Pye-Smith, 2003).

    There have been certain possibilities to achieve species diversity on degraded lands by afforestation of fast-growing tree species. All tested species of Acacia, Teak and Eucalyptus seem to be the favorable tree for the growth of the ground vegetation. Species diversity indices of their ground flora vegetation showed higher values than those of open control area. Diversity index (H) was 3.795 under A.catechu, 3.595 under T. grandis and 3.173 in open bhata land, species richness (SR) was 22, 20 & 15, respectively (Verma 2000); Eucalyptus tereticornis suported the maximum species richness (36), followed by Acacia auriculiformis (26), then Tectona grandis (20) and the lowest was recorded for open area (15) (Thapliyal, et al., 2002). Maximum species was recorded in rainy season and minimum in summer under E.tereticornis (Bahar and Jain, 2002). Under Poplar plantation, Lodhiyal (2001) found the short-lived species with maximum H in older stand (9-yr old) and lower H in the younger stands. This is due to lower nutrient levels in older stands and a higher level in the youngers.

    On imperrata-grasslands, fast-growing species plantations of G. arborea, A. mangium and A. crassicarpa in Imperata grassland had early significantly suppressed the development of Imperata cylidrica (reduced dry biomass) and favored the development of other grasses and shrubs, viz., Chromolaena odorata and Clibadium surinamense. There is a significant linear correlation existed in regression analysis between distance of planted trees and grass biomass for four tested tree species A.mangium (y= 1.547x-1.426, r2= 0.95), A. crassicarpa (y= 2.083x-0.669, r2= 0.97), Gmelina arborea (y= 0.926x- 0.886, r2= 0.75) and Paraserianthes falcataria (y= 2.926x- 2.696, r2= 0.96) (Otsamo, 2002).


    Establishing plantations might sound like a laudable activity. Trees, after all, have many

    virtues. They convert water, sunlight and carbon dioxide into wood and oxygen, and it is

    frequently claimed that they regulate the water cycle, stabilize steep slopes against erosion

    and prevent flooding. Trees also provide a habitat for countless creatures and micro-

    organisms, and hundreds of millions of people rely on them for timber, firewood, fruit, nuts,

    resins and other products. Appropriate monoculture plantation of fast-growing species like

    Acacia, Teak, Poplar, etc., has proved to be one of applicable approach for afforestation

    programs, both in economical and ecological purposes, particularly, the only effective choice

    to initially reforest the degraded areas, then to transform into permanent forest (Apel, 2004).

    During recent years the planting of large areas of fast growing trees has sparked off much

    controversy, especially in the developing world. Critics of these “fast-wood” plantations

    include environmentalists, who argue that they are replacing natural forests and causing harm

    to wildlife, water resources and the soil, and local communities, who complain that

    plantations are taking over land which previously provided them with the means to feed

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    themselves and earn a living (Cossalter and Pye-Smith, 2003). This has become a major issue,

    particularly where “fast-wood” plantations are a significant land use.

    100 years have seen a major reduction in global forest cover, especially in the tropics.

    Natural forests have been replaced by a variety of simple agricultural monocultures such as

    rice or industrial forest monocultures made up of fast- growing exotic species such as Pinus,

    Eucalyptus, Acacia or Tectona (Lamb, 2003). Around the world, biological communities that

    took millions of years to develop are being devastated (Sharma, 2003). About 20 per cent of

    all species are expected to be lost within 30 years and 50 per cent or more by the end of 21st

    century (Myers, 1993; Sharma, 2004). The current decline in biodiversity is largely the result

    of human activities from habitat destruction, over-harvesting, pollution and inappropriate

    introduction of exotic plants and animals. The diversity of natural ecological communities has

    never been more valued than they are now, as they become increasingly threatened by the

    environment crises. Efforts are, therefore, needed to conserver biological resources