Successive droughts over past two years have brought focus back on planting trees. The idea is drawn from the age-old wisdom that forests are necessary for rain. However, the persisting demand for fuel, fodder and other forest products, and forestland for infrastructure development, is severely impacting forests. To meet the challenge of increasing demand for forest products and to address forest degradation, forest practitioners raise plantations following sound ecological principles.
According to the UN Food and Agriculture Organisation (FAO), forest plantations constitute 7% of the total 3.999 billion hectare (1 billion = 100 crore) of the forests globally. In India, since independence, forest plantations have been raised over 55 million hectare (mha; 10 million = 1 crore), which is about 17% of the total geographical area of the country (328.7 mha).
Similarly, in Karnataka, forest plantations over 2.345 mha have been raised up to 2014-15, which is ab-out 12.3% of the area of the state (19.2 mha). Thus the commonly held perception that an area equal to the size of the state has been afforested till date is not based on facts.
Forestry plantations in Karnataka consist of two types of tree species, namely, long-rotation and short-rotation species. Rotation-age of a tree species in forest management denotes the age at which a tree is felled and utilised. Long-rotation species are either not targeted for felling (for example, honge, tamarind and neem) as they provide pods, seeds, fruits etc or are felled at a high maturity age (teak is felled at 80 years or more). Short-rotation species (poplar, casuarina, acacia, silver oak and eucalyptus), on the other hand, are raised with the objective of providing fuel wood, pulpwood, poles and small timber and are normally felled after 8-15 years of planting.
Of the 2.345 mha plantations raised by the Karnataka Forest Department (KFD) and forest corporations in the state, 0.968 mha (5.2% of the area of the state) are long-rotation species plantation and remaining 1.377 mha (7.1%) are short-rotation species plantations. The proportion of long-rotation to short-rotation species plantations is 41:59. The short-rotation species plantations show up as forest cover for about 10 years and then disappear since reaching rotation-age they are felled.
However, the long-rotation species plantations remain for longer time and contribute to forest cover on a more permanent basis. Further, long-rotation species planted in contiguity with the existing forest areas show up as expanding forest cover. However, those planted away from forests in isolated small blocks (less than 1 ha) or as linear strips (road sides, canal banks etc) add to overall tree cover, which is in addition to the forest cover. As per the forest and tree cover assessment report by the Forest Survey of India (FSI), the area under tree cover in Karnataka has build up to 0.56 mha.
The estimate for the extent of long-rotation species plantations in Karnataka (0.968 mha) includes lavender, spices, tea and cane plantations which do not actually contribute to forest cover. Excluding such plantations, the best estimate for total extent of long-rotation species plantations that could contribute to forest cover is 0.86 mha. If all of these plantations were carried out on the barren lands and had matured, the forest cover in the state would have increased by 0.86 mha, which is 4.5% of the area of the state.
However, majority of these plantations were carried out in the forestlands under the administrative control of the KFD. The objectives of raising such long-rotation species plantations over forestlands include: to fill the gaps in forest canopy; to restore degraded forest areas; to improve the can-opy density of a forest; or, to raise plantations of commercially important timber species (teak) by removing a mixed crop of native species (this is no longer in practice now).
These plantations, carried out with forest restoration and improvement objectives, contribute by improved quality of forests and can hardly be expected to expand the forest cover. Plantation efforts of the KFD have served largely to mitigate the impact of ever-increasing demand for biomass from forests.
Efficacy of plantations
A recently concluded study for Western Ghats Karnataka Landscape has shown that plantations carried out in the eastern fringes of the Ghats, which are under high biotic pressure, have successfully restored tree cover in such areas. Raising plantations in the freshly evicted encroached forestlands have helped in securing such lands against re-encroachment.
It is believed that the plantations raised in the forest-community interface zones have, to a large extent, successfully buffered the biotic pressure and thereby helped in conservation of remaining natural forests. It is only logical to expect that if plantations in forest-community interface zones were not raised, more natural forests would had been subjected to degradation leading to loss of ecosystem services such as reduction in quality potable water, loss of soil and loss of biodiversity.
According to a recent study, the observed data from the Indian Meteorological Department shows that rainfall in the Western Ghats has reduced by about 7% since 1950. Apart from the atmospheric circulation related causes, the fragmentation, degradation and loss of forests in the Western Ghats may also have contributed to such reduction in rainfall through weakening of ‘forest hydrological pump’ action of the Western Ghats forests.
Raising plantations of native tree species can help restore forests and potentially mitigate the declining trend of rainfall in the Ghats. The rainwater received in the Western Ghats forms the basis for life in peninsular India.
Planting activity in the state becomes particularly important in view of the need for securing forests against climate change risks. Scientifically drawn plantation programmes can potentially help forests to adapt under future climate. Further, in view of the growing water stress and impacted food production, there is a need to intensify plantation programme in Karnataka by availing of all the available lands and involving all the stakeholders.
(The writer is Additional Principle Chief Conservator of Forests, Water Resources Department, Karnataka. Views are personal)
