The Montane Evergreen Forest, Bisale Region

The Bisale State Forest, with an area of about 15 square miles occupies the south-western extremity of the Western Ghats of Mysore. The country is hilly, with altitude ranging from 450 to 3,521 feet. It is covered by evergreen forest, Warmth and moisture determine the nature of growth. Most of the rain falls in the south west monsoon. The humidity, especially during the rainy season, is very high and even in the other seasons, it approaches the point of saturation under the forest roof during the early hours of the morning. Although the forest is never bare of leaves, the growth and reproductive activities are confined to a short time in the April. During the rainy season there is little or no growth. The main growing season is after the rains and before the dry season. The flowering season corresponds to the driest season of the April-January to March. The fruits ripen generally in May and June. Three principal zones of growth are: the semi-evergreen passing on to the deciduous under 800 feet; the evergreen zone from 800 to 2,500 feet; and the bare, grassy hill-tops, over 2,500 feet. The transition from the deciduous through the semi-evergreen to the typically evergreen is gradual but that from the evergreen to the bare hill-tops is abrupt. The evergreen flora shows two distinct associations of tree species, the Dipterocarpus-Vateria type and the Vateria-Elaeocarpus type. The latter is an edaphic variant on the former. The evergreen type is described in detail, along with its storeyed vegetation. The deciduous type has been mentioned briefly. The ecological factors affecting tree growth in these forests and leading to the formation of the climax type of vegetation have been discussed.