Green leaves and vegetation play a critical role in climate change. We know that during photosynthesis, plants use carbon dioxide and give out oxygen, thereby reducing atmospheric carbon dioxide. It is said that a big tree uses 1.75 tonnes of carbon dioxide and releases 2.25 tonnes of oxygen per hour.
But how does one measure or assess the green wealth of a region? This can be indicated by comparing the surface area of all the leaves to the land area possessing it. Consider one arecanut farm. Imagine that all the green leaves are removed and arranged on the ground area of the farm touching each other without gaps or overlaps. The leaves may cover the land twice at the maximum.
Consider one healthy jackfruit tree. Imagine arranging the leaves under the crown area next to each other without gaps or overlaps. The leaves may cover the land in which it is grown 500 times or more.
There are many forest patches in the State; some have lost their green wealth while others haven’t. If one takes an estimate of the loss of greenery over a 100-year-period, one can understand the loss of green wealth.
The forest area in Agumbe includes rainforests or super wet evergreen forests with leaves that covered the land area under it 25,000 times, a hundred years back. The same is not true today. Rainforests are such sensitive ecosystems that it is difficult to say how and when the damage will be rectified. The reduction of leaves in the area outside the forest may be 90 per cent in the last hundred years. Also, the development of private holdings in the last hundred years might have reduced the leaf cover.
Hundred years back, the forest area near Shimoga, comprising 9,000 hectares, was a very good stretch of moist deciduous forests without any gaps or enclosures with leaves covering the land area of the tree 2,500 times. Today this forest region is full of expanding enclosures set up by the families displaced by Linganamakki submersion on one side and is under pressure from the developing Shimoga City on the other side. While forming reserve forests, considerable forest areas are left for the use of people and their cattle. All such areas are now reduced to blanks or have been encroached; the reduction of leaves may extend to 95 per cent.
Teak plantations and pulp plantations also have reduced leaf cover considerably. When a moist deciduous forest is converted into a teak plantation, leaves dominate only in single strata with thick ground growth. The teak crown and ground growth may amount to 1,000 times leaf cover, a reduction of 60 per cent from 2,500 times.
Elsewhere in the State, in dry regions such as Holalkere of Chitradurga district, trees such as tamarindus indica (hunse) have in the past been felled for firewood. Here, the leaf cover has dropped by 75 per cent.
Most of the arecanut plantations of today were once evergreen or semi-evergreen forests. So, earlier leaf area of 10,000 times has been reduced to 10 times now — a whopping reduction. The same is the case with coconut plantations and coffee plantations. Almost all coffee plantations were once wet evergreen forests.
About 50 per cent of today’s agricultural land has been converted from forest areas in the last hundred years. It is difficult to assess the leaves of agricultural crops as they are short, rotational and seasonal.
These examples are indicative of drop in leaf cover, and not exact assessments. Yet, they give us a fair idea of the reduction in greenery over the years.
The solution lies in increasing leaf area at least four times in three decades. This needs to be attempted if we are keen on checking climate change. Intensive planting is crucial, especially in areas along river beds.