Presentation on theme: "Introduction A forest is an area with a high density of trees (or, historically, a wooded area set aside for hunting). These plant communities cover large."— Presentation transcript:
1 IntroductionA forest is an area with a high density of trees (or, historically, a wooded area set aside for hunting).These plant communities cover large areas of the globe and function as animal habitats, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the Earth's biosphere.The size and slow growth of trees make forests appear stable and permanent, but infact they are dynamic sites of ongoing processes such as Tree-growth, death and Soil formation.
2 MethodologyThe references that bring out summarized account of the forests world-over and the threats being faced by them,have also tried to focus on the more specific threats being faced by each of the forest types described.From varied sources of information, the present general status of the field of Forest genetics and biotechnology and its scope has been provided.The possibilities of using these technologies to attain qualitative and faster results in terms of afforestation, reforestation and forest conservation has also been provided.
3 EcologyForests can be found in all regions capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency is too high, or where the environment has been impaired by natural processes or by human activities.Forests are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation communities.The inhabitants of forest communities interact in complex ways.Trees also serve as temporary respositories for mineral nutrients in ecosystemsNatural or human destruction of forests alters NUTRIENT CYCLES, especially in the case of NITROGEN CYCLE
4 The process of soil development, aided by soil organisms, occurs in all forests. Depending on environmental conditions, different tree species will be dominant at different successional stages.The characteristic group of tree species in a given area is referred to as forest type.Within each type, certain species may be found most commonly under specific soil and climate conditions and at certain times after disturbance
5 Types of forestsForests are differentiated from woodlands by the extent of canopy coverage. In a forest the branches and foliage of individual trees often meet or interlock, but there can be gaps of varying sizes within an area referred to as forestTree species can be divided into groups based on their evolutionary origins;HolarcticNeotropicPaleotropicCapensisForest communities with different genetic backgrounds that grow under similar soil and climate conditions in different parts of world have many similar structural characteristics.Thus forests can be classified as major parts of many BIOMES.
6 ForestryForestry involves the use and management of forest resourcesThe uses of forests can be divided into 2 categories: nonconsumptive and consumptive..Nonconsumptive uses, which remove little from forest, include watershed protection; wildlife and fish habitat; recreation and aesthetic uses.Consumptive uses, by definition, involve extraction of products from forests; this often requires harvesting of trees.
7 ManagementForests are managed for a variety of objectives, ranging from carefully tended plantations to relatively natural areas of no cutting and minimal protection.The intensity of management depends on the growth potential of the forest and various economic and political objectives.The ultimate unit of forest management is the “stand”.A stand is a group of trees of uniform age, species, structure, and growth conditions.Four methods are use to remove trees from forest stands.The most radical is clearcutting or the cutting of all the trees at one timeThe other methods are seed tree cutting, or the cutting of all the trees except for a few trees for reseedingThe shelterwood cutting, or the removal of an old stand of trees in a series of cutting extended over several yearsThe selection cutting or the removal of a few mature trees
8 Each system has its advantages and disadvantages; proper methods must be chosen on the basis of management goals and conditions of the stand in question.The system of LOGGING the stand by clear cutting is appropriate where trees become established and grow without shadeInappropriate selection cutting of mixed-species forests in many parts of the world has left stands of diseased trees of little value that prevent vigorous trees from growing.Silvicultiral techniques constantly change with technological advances. They involve use of fire, machinery, chemicals for preparing stands for regeneration and for removing competing plants; nurseries for growing seedlings; genetic improvements resulting in more efficiently growing trees; fertilizers for increasing growth; remote control machineries for pruning unwanted limbs.It might seem odd to mention fire as one means of forest management, because the enormous destructiveness of great forest fires- such as the one that swept Yellow stone National Park in is well known.
9 ProductsThe use of forests to obtain WOOD, chemicals and other products is consumptive.About half of wood harvested in the world is used directly for fuel.Wood has been used for LUMBER for construction purposes for thousands of years.PAPER was first made from wood about 150 years ago, & it is still made primarily from wood.The cellulose fibers in wood can also be used to make RAYON, photographic film, artificial sponges, synthetic lacquers and other plastics.Various chemicals are made from by-product of pulp and paper manufacture and from independent distillation of wood; these include charcoal, acetic acid, methanol, various oils, and medicinal chemicals.Turpentine and tar may be obtained from destructive distillation or by scarring and scarping the wound of living pine trees.Maple sugar is obtained by taking sap from interior of living maple trees and various trees provide other products.
10 ConservationConservation is the planned management of natural resources to prevent their neglect, exploitation, and destruction.One objective of conservation is prevention of unintentional destruction of forests by disease, insects and other agents.The objectives of conservation have changed along with changes in such related areas as understanding of forest process, human values themselves, demands on forest, availabilities of various resources and technologies.Aesthetically unique areas and high-quality watersheds were set-aside as national parks and forests.In the past few decades, increases in mobility, leisure time, and disposable income have led to more interest in conserving forests for nonconsumptive purpose.Forests have been used for consumptive purpose throughout the world; in tropical regions, where forest soil grow rapid rate.
11 Three solutions to deforestation problem have met with some success; The use of local people in forest management;The “agroforestry”, or the planting of trees in croplands and pastures,The use of financial resources of developed countries.The Food and Agriculture Organization of UN has gained support for the protection of world’s forests and their role in rural development.As scientific knowledge of forest growth expands and a better understanding of detrimental effects of human activity develops, conservation efforts are working to turn the tide and prevent demise of forests as source of consumptive product’s, clean water, wildlife, fish habitats and recreation areas.These efforts are being applied globally to prevent the neglect, exploitation and destruction of forest.
12 Humans and rain forests Throughout history, humans have encroached on rain forests for living space, timber and agricultural purposes.In vast portions of upland tropical forests, the practice of “Shifting Cultivation” has caused deterioration of the primary forest.On the island of Java, the lowland primary forest has been almost totally removed and replaced with rice fields or plantation crops such as rubber.Logging for exotic tropical wood has growth extensively in recent decades, leading to rapid deforestation of rain forests in few placesNumerous organizations are now attempting to reduce rate of the loss.As part of response to deforestation, a number of tropical rain forest sanctuaries have been established around the world.Pharmaceutical companies have also taken an interest preserving tropical rain forests, which may have plants of medicinal value among their many plants.
13 Forest genetics and Biotechnology The subdiscipline of genetics is concerned with genetic variation and inheritance in forest trees. The study of forest genetics is important because of unique biological nature of forest trees and because of social and economic importance of forests, knowledge of forest genetics is important for conservation, maintenance, and management of healthy forest ecosystem; and development of programs which breed high-yielding varieties of commercially important tree species.Variation in natural forestsEven though trees in a forest may be of the same genotype, they could however slightly differ in their phenotype. It is now possible that this can be changed by a method called CLONING.Geographic variation in natural forestsThe term “provenance” refers to a specific geographical location within the natural range of a tree species. Genetic difference among provenances can often be quite large, especially for wide-ranging species occupying many diverse climates.
14 Genetic variation with forest stands In addition to genetic differences among provenances, there is usually substantial genetic variation among trees within same forest stand. Most forest tree species maintain very high levels of genetic diversity within populations.Forest tree breedingBeginning with natural genetic variation that exists in undomesticated tree species, tree breeding programs use selection, breeding, and other techniques to change gene frequencies for a few key traits of chosen species. Use of a genetically improved variety for this reforestation means that the new plantation will grow faster and produce wood products sooner than did the previous stand.
15 Forest biotechnologySeveral laboratory techniques of molecular genetics and biotechnology promise to make major contributions to forest genetics and tree breeding in near future:Somatic embryogenesis is a technique to duplicate selected trees asexually from their vegetative cells, & this allows best trees to be immediately propagated commercially as Clones without sexual reproductionGenetic mapping of some important tree species is well under way, and these maps will be useful in many ways to understand genetic control of important traits, such as disease resistance.Maker-assisted selection is use of some kinds of genetic maps to help select excellent trees at very early ages based on their deoxyribonucleic acid (DNA) genotype as assessed in a laboratory.Functional genomic analysis is an exciting new field of genetics that aims to understand the function, controlled expression and interaction of genes in complex traits such as tree growth.Genetic engineering or genetic modification is the insertion of new genes into trees from other species.
16 Conservation of genetic resources For commercially important species of forest trees, gene conservation is practiced by tree breeding programs to sustain the genetic diversity needed by program. However, conservation of genetic diversity is of major global concern and is important for all forest species toMaintain the health and function of forest ecosystems.Sustain the genetic diversity of noncommercial species that may eventually have economic value.There are many current medicinal and other nonwood products produced by trees, and there are many more future products as yet undiscovered.There are two broad categories of gene conservation programs. In situ programs conserve entire forest ecosystems in forest reserves, national parks, wilderness areas, or other areas set aside for conservation purpose.
17 Indian rain forestIndia's unique topography, terrain, climate and vegetation, brings out natural diversity that cannot be witnessed anywhere else in the world.Tropical forests in India's east present a total contrast with the pine and coniferous woodland of the Western Himalayas.
18 Wildlife conservation in India But due the growing impact of deforestation, few concerned animal lovers are making continuous efforts to save the endangered species as well as those who are on the verge of extinction and save the world from loosing its green heritage.Some of the projects and wildlife conservation programmes in India include Project Tiger, which has been till now the most successful one in protecting and preserving the tiger population.There is the Gir National Park, which is only habitat existing for Asiatic lions in India.The Kaziranga Sanctuary is Assam is another remarkable example of saving the endangered Rhinoceros.There's Periyar in Kerala conserving the Wild Elephants and the Dachigam National Park doing the same to save the Hangul or Kashmiri Stag.
20 ConclusionThis is a paper which mainly comprises of a review of general and popular information available and provides a summarized overview of the forests of the world. It is mainly targeted at the student community at the high-school, pre-university and Undergraduate levels. In view of the pressures of habitat loss, change in the environmental status in view of increasing human threats and the resultant ecological pressures, the scope of the field of forest genetics and biotechnology has been emphasized. Keeping the accounts of the status of forests the world over, special emphasis has been provided regarding Indian forests. The major threats being presently faced have been collated. Based on these experiences and considering the powers vested in the Indian Forest Act of 1927and the possibilities available in the field of Forest genetics and biotechnology presently, an attempt has been made to arrive at a few suggestions.