Roughly speaking, at least four climatic zones with many sub-types, may be recognized: the truly tropic, intensely hot and wet (over 75 inch rainfall), prevailing on the plains and tablelands of the lower half of the peninsula; the hot and dry (below 15 inch rainfall) climate of the Northwestern Indus plain and plateau; the moderately warm and dry to humid (30-75 inch rainfall) climate of the Ganges plain and central plateau; and the temperate to alpine, humid climate of the Himalaya mountains, with snow and ice in winter, and moderate heat in summer.
In keeping with this great diversity of climate, both as to temperature and humidity, there is a great variation in the character and development of the forest cover. At least six types can be recognized, namely the evergreen forest, found along the West coast, in Burma, Andaman Islands, and the sub-Himalaya zone, which is composed of broadleaved species with a dense undergrowth of small trees and tangled lianas (vines), but few shrubs, as is characteristic of most tropical forest; the deciduous forest, mainly in the interior of Central India, with Sal, Teak and Ironwood as characteristic trees; the arid region forest, found in the Punjab, in Raiputana, and in Sindh, of varying composition, from the open shrub forests of the latter province, composed of acacias, tamarisk and mesquite, to the denser, more diversified, dry, low tree forest of the former; the alpine coniferous forest of the Himalayas and of the mountains of Afghanistan, Belutchistan, and Burma, composed of pine, deodar, juniper, with oak, walnut, boxwood, approaching our own forest types. In addition, there may be segregated the coast forest, of small extent, composed of trees which, like the mangrove, will bear salt water; the overflow forest along rivers; and river forests in the desert regions, of which latter large areas exist.
The natural differences in the forest cover are emphasized by the action of man, who for many centuries has waged war against the forest, clearing it permanently or temporarily for agricultural purposes, or else merely burning it over to improve grazing facilities, or for purposes of the chase.
Statistics, except of government properties, are somewhat doubtful. Apparently, the forested area of the whole of India comprises somewhat over 40 per cent. of the land area. The government forests, settled and unsettled, represent at present about 24 per cent. of the area under British rule (149 million acres), not over 20 per cent. being under cultivation, leaving about 56 per cent. either natural desert, waste, or grazing lands.
The great forests of India are in Burma; extensive woods clothe the foothills of the Himalayas and are scattered in smaller bodies throughout the more humid portions of the country, while the dry northwestern territories are practically treeless wastes. Large areas of densely settled districts are so completely void of forest that millions of people regularly burn cow dung as fuel, while equally large districts are still impenetrable, wild woods, where, for want of market, it hardly pays to cut even the best of timbers.
The great mass of forests in India are stocked with hardwoods, which in these tropical countries are largely evergreen, or nearly so, although the large areas of dry forest are deciduous by seasons; only a small portion of the forest area is covered by conifers, both pine and cedar, these pine forests being generally restricted to higher altitudes in the Himalayas. The hardwoods, most of which in India truly deserve this name, belong to a great variety of plant families, some of the most important being the Leguminosæ, Verbenaceæ, Dipterocarpeæ, Combretaceæ, Rubiaceæ, Ebenaceæ, Euphorbiaceæ, Myrtaceæ, and others, and a relatively small portion represented by Cupuliferæ and other families familiar to us. The most important, valuable species are Teak, Sal, and Deodar.
In the greater part of India the hardwood forest consists not of a few species, as with us, but is made up, like most tropical forest, of a great variety of trees unlike in their habit, their growth, and their product; and, if our hardwoods offer on this account considerable difficulties to profitable exploitation, the case is far more complicated in India, several thousand species entering into the composition. In addition to the large variety of timber trees there is a multitude of shrubs, twining and climbing plants, and in many forest districts also a growth of giant grasses (bamboos), attaining a height of 30 to 120 feet, which is ready to take possession of clearings. These bamboos, valuable as they are in many ways, prevent often for years the growth of any seedling trees, and thus form a serious obstacle to the regeneration of valuable timber. The growth of timber is generally quite rapid, although to attain commercial size, Teak requires usually a rotation of 150 years. But in spite of their rapid growth and the large areas now in forest capable of reforestation, India is not likely—at least within reasonable time—to raise more timber than it needs. In most parts of India, the use of ordinary soft woods, such as pine, seems very restricted, for only durable woods, those resisting both fungi and insects (of which the white ants are specially destructive), can be employed in the more permanent structures, and are therefore acceptable in all Indian markets.
At present, Teak is the most important hardwood timber, while the Deodar (a true cedar) is the most extensively used conifer. Teak occurs in all moist regions of India except the Himalayas, grows usually mixed with other kinds, single, or in clumps, is girdled two or three years before felling, is generally logged in a primitive way, commonly hewn in the woods and shipped—usually floated—as timber, round or hewn, and rarely sawn to size.
In 1905-6, the cut in the State forest area was 240,000,000 cubic feet, timber (25%) and fuel, of which 20 per cent. was given to grantees or those holding rights of user free of charge, and less than 2 per cent. was exported. In addition, over 200 million bamboos and nearly two million dollars worth of by-products, such as lac, caoutchouc, cutch, gambier, myrobalans, were secured.