ANALYSIS OF WOODY PLANT DIVERSITY
Phytogeography is the study of origin, environmental relationships and distribution of plants both in time and space. It is divided into two – descriptive phytogeography describes the actual distribution of plants in different parts of the world and interpretive phytogeography explains the reasons for such a distribution. Woody plant communities are a unit of vegetation having a definite and regular assemblage of plant populations that forms a conspicuous local feature of the area. Study of plant communities is known as phytosociology.
Woody plants are either trees & shrubs that produces wood as its structural tissue. Total forest and tree cover in india is 789,164 containing very dense, moderate and open forest (State forest report, 2013). Based on type of seed produced woody plants are of two types gymnosperms (ovules is exposed) and angiosperms (seeds found inside the fruit). Total number of gymnosperms in india is 74 having 8 endemic and 7 threatened species whereas in angiosperms is 18043 in numbers having 4036 species are endemic and 1700 are threatened (Chapman, 2009, Singh & Dsah, 2014). Jurassic period, is the best time for gymnosperms. About 16 genera and 53 species of living gymnosperms have been reported in India. The four phyla of gymnosperms are differentiate to each other of their leaf structure. In coniferophyta having needle or scale like leaves, cycadaphyta having pinnate leaves, gingkophyta having leathery leaves with a wax layer on both sides and gentophyta having fan shaped leaves. Radiation of angiosperms marks the transition from the Mesozoic era to the Cenozoic era. In 1990s, plant taxonomists divided the angiosperms into two main classes i.e. monocots are about 65,000 species, ex. bamboos, grasses & palm whereas in dicots is about 175,000 species, example sal, teak & neem.
The woody diversity is mostly rich in tropics because tropics have had a more stable climate than the temperate zones. The woody diversity is important for commercial, biological, scientific, aesthetic and ecological point of view. The loss of woody diversity by deforestation, land conversion, invasive species, fragmentation, land quarrying and development activities. The afforestation, preventing or reducing deforestation, preventing over grazing, setting up national parks & biosphere reserves etc, undertaking social forestry programs like van mahotsav, chipko and movement for planting and protecting trees on a large scale is to be protect the woody diversity. Woody plant diversity is essential for the enhancement of food production, ecological balance, mitigation of environmental pollution and natural calamities. We need joint effort from all section of people of the society for conservation of woody plant diversity.