Patterns of forest use and its influence on degraded dry forests

The present study conducts at the dry deciduous forest in the plains of Tamil Nadu, South India, the pattern of forest utilisation, its socio-economic background as well as its impact on the structure of the forest vegetation. The study area, about 40 km² in extent, includes a Reserved Forest of 10 km² and 19 adjacent villages. The forest is situated on the Kadavakurichi, a small hillock in the centre of the study area. In order to evaluate the relationship between forest utilisation practice and the condition of the forest, the study area was divided into five sub units (watersheds) which differed in the intensity of use. Each watershed was comprised of a part of the Reserved Forest and the villages next to it. Data on forest structure where collected from 500 sampling plots which were demarcated in an even grid patter covering the entire forest. In addition, a small forest around a temple located on the hillock (Temple Forest), which is about 0.15 ha in size and showed well developed, less disturbed vegetation, was surveyed. Through structured interviews among households involved as well as those not involved in product collection, information on forest product utilisation was collected. The Kadavakurichi Reserved Forest consists of thorny scrub averaging two meters in height, with patches of tree savannas up to pure grasslands, kept open through annual fires. The structure of the forest as well as the observed traces on the plants indicates strong degradation. Within the 500 plots, 149 plant species were found out of which the majority (31%) were tree species. Trees covered 31% of the forest area, with an average wood volume index of 0,03m³. Commiphora berryi and Euphorbia antiquorum were clearly the dominating species in both frequency and coverage. Conducting to this, the structure of the Temple Forest was different, with almost 100% tree coverage. Individual trees were up to 12 meters tall and showed a wood volume index of up to 3 m³. The Kadavakurichi RF can be classified as a degraded form of the Dry Deciduous Forest as well as a degraded Dry Evergreen Forest. The composition of species in the Temple Forest indicates a high ratio of evergreen trees if development under low or non human impact takes place. The socio-economic settings of the households that utilise forest products differed significantly from that of the household that do not utilise forest products. Forest product collection was concentrated on three of the five watersheds. Fuelwood was clearly the predominantly used forest product. Regression models were use to test whether the different intensity of forest utilisation determines the vegetation structure. The results showed that the intensity of product collection can not explain the difference in the vegetation fully and indicated the existence of another, stronger influence. This was attributed to forest fires, which occurred throughout the entire forest at different frequencies. The results of the interviews and the observations done in the study period showed that the fires where almost solely of human origin. The urgent need to involve the fire in forest management strategies and the creation of the required political frame work is expressed. In addition suggestion for a management of the Kadavakurichi Reserved Forest under consideration of forest fires are made.