Influence of environment on physiology of plantation forests

摘要

The rising demands for wood-based industries from forests, due to increasing population pressure, energy crisis and ever-increasing pressure for agriculture and other urban uses, the foresters at present are facing challenges from many quarters. Necessarily, attempts have to be made; in fact are already initiated for raising large scale plantations of eucalyptus, poplar, tropical pines, bamboos, acacias, casuarina, etc. To meet this pressing situation, we have to select plantation species which could be concentrated in areas of maximum productivity, besides making optimum utilization of' degraded areas for afforestation (Pandey et al. 1989). Circulation of nutrients also plays an important role in forest and plantation ecosystems. These circulatein relatively large amounts within the ecosystem. Much of the nutrient uptake by trees is returned to the soil by way of litter fall, etc., but an appreciable amount is retained by the bole, bark and branches, which are usually harvested and removed fromthe site. This loss of nutrients is greater with intensive utilization of fast growing short rotation species. The study on biological productivity and cycling of nutrients is, therefore, necessary with a view to maximizing productivity from our limitedforest areas (Shanmughavel, 1995).