Monday, 23 January 2017

natural vegetation

India is one of the twelve mega bio-diversity countries of the world. With about 47,000 plant species India occupies tenth place in the world and fourth in Asia in plant diversity. There are about 15,000 flowering plants in India which account for 6 per cent in the world’s total number of flowering plants.
What is Natural vegetation Or Virgin vegetation?
Natural vegetation refers to a plant community which has grown naturally without human aid and has been left undisturbed by humans for a long time. This is termed as a virgin vegetation.
Huge diversity in flora and fauna kingdom is due to the following factors.
 Relief which include Land and Soil.
Climate which include Temperature, photoperiod and precipitation.
(a)    land- The nature of land influences the type of vegetation.
                The fertile level is generally devoted to agriculture.
                The undulating and rough terrains are areas where grassland and woodlands                    develop and give shelter to a variety of wild life.
(b)   Soil-  The sandy soils of the desert support cactus and thorny bushes while
Wet, marshy, deltaic soils support mangroves and deltaic vegetation.
The hill slopes with some depth of soil have conical trees.
© Temperature-  fall in the temperature affects the types of vegetation and its growth, and changes it from tropical to subtropical temperate and alpine vegetation.
(c)    Photoperiod- The variation in duration of sunlight at different places is due to differences in latitude, altitude, season and duration of the day also affected typs of vegetation.
(d)   Precipitation- Areas of heavy rainfall have more dense vegetation as compared to other areas of less rainfall.
Q why forests are important for human beings?
Ans Forests are renewable resources and play a major role in enhancing the quality of environment.
They modify local climate, control soil erosion, regulate stream flow, support a variety of industries, provide livelihood for many communities and offer panoramic or scenic view for recreation.
It controls wind force and temperature and causes rainfall. It provides humus to the soil and shelter to the wild life.
Ecosystem
All the plants and animals in an area are interdependent and interrelated to each other in their physical environment, thus, forming an ecosystem. Human beings are also an integral part of the ecosystem.
Q How do the human beings influence the ecology of a region?
Ans They utilize the vegetation and wild life.
The greed of human beings leads to over utilization of these resources.
They cut the trees and kill the animals creating ecological imbalance.
As a result some of the plants and animals have reached the verge of extinction.
Define Biome.
A very large ecosystem on land having distinct types of vegetation and animal life is called a biome.
TYPES OF VEGETATION The following major types of vegetation may be identified in our country
(i)                 Tropical Evergreen Forests
(ii)               (ii) Tropical Deciduous Forests
(iii)              (iii) Tropical Thorn Forests and Scrubs
(iv)             (iv) Montane Forests
(v)               (v) Mangrove Forests.
Tropical Evergreen Forests.
Heavy rainfall (200cm)  areas of the Western Ghats and the island groups of Lakshadweep, Andaman and Nicobar, upper parts of Assam and Tamil Nadu coast.
trees reach great heights up to 60 metres or even above.
There is no definite time for trees to shed their leaves. these forests appear green all the year.
 Common trees are ebony, mahogany, rosewood, rubber and cinchona.
The common animals are elephants, monkey, lemur and deer. The one horned rhinoceros are found in the jungles of Assam and West Bengal.
Tropical Deciduous Forests.
They are also called the monsoon forests and spread over the region receiving rainfall between 200 cm and 70 cm.
  Forest-type shed their leaves for about six to eight weeks in dry summer.
These forests exist, northeastern states, along the foothills of the Himalayas, Jharkhand, West Orissa and Chhattisgarh, and on the eastern slopes of the Western Ghats.
Teak is the most dominant species of this forest. Bamboos, sal, shisham, sandalwood, khair, kusum, arjun, mulberry are other commercially important species.



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