Location and topography National budget

108 3. Causes of forest degradation

3.1 Direct causes

In Nepal, forest degradation is identified as a major environmental problem. Most of the forests in the mid-hills are under community management and are well managed Kanel 2004. Forests in the Terai, Shiwaliks and High Mountains are under severe pressure from biotic interference. In general, forests under government management face a high degree of uncertainty MoEST 2006. Crown cover is often taken as a proxy indicator to detect forest degradation. It may, however, not be a sufficient indicator to determine forest degradation. Canopy reduction will reduce carbon sink potential, but it may enhance watershed conservation and biodiversity. The understorey may remain intact. Conversely, loss of ground vegetation or understorey, which may not be detected, could also be a key degradation element, as it affects ecosystem resilience. Sharma and Suoheimo 1995 found that about 45 percent of trees in the Makawanpur and Rautahat districts are affected by rot diseases. Acharya et al. 2012 found degradation of existing forest stock resulting from repeated logging practices; for example the sal forest Shorea robusta used to be well stocked 60 percent basal area, but following repeated cuts, it became a Terai hardwood forest sal basal area 20 percent. The silvicultural practice of ‘selection felling’ is resulting in degradation of previous sal Terai hardwood forests to Terai hardwood Rautianien 1994. It can be inferred that the overexploitation of this species has gradually changed sal dominance. MoEST 2006 estimated that over 28 percent of the total land of the country is undergoing desertification Table 5. Table 5. Land area under degradation in Nepal Source: MoEST 2006. Besides poor forest management, several other drivers have been identified. They include: •฀ Increasing demand for cultivable land – as Nepal has an overwhelmingly agrarian economy, with over 49 percent of the 29 million inhabitants living on 0.6 million ha of cultivable land in the hills, heavy encroachment on forest has continued. •฀ Land acquired for development projects – forests have been targeted for conversion to agriculture, horticulture, plantations, industrial development, roads and other infrastructure development. •฀ Increasing demand for fuelwood – of the total fuel required, 86 percent is fuelwood CBS 2010, the rest being animal dung and agricultural residues CBS 2011. While people are beginning to switch to other fuels, 65 percent of the population is still dependent on wood for their cooking needs CBS 2013. •฀ Increasing demand for fodder and bedding material – the Nepalese agrarian economy is dependent on livestock rearing. According to CBS 2010 there were 7.19 million cattle, 4.83 million buffalo, 8.76 million goats, 0.79 million sheep and 1.06 million pigs. Livestock impose on forests in two ways, i.e. year-round grazing and lopping of trees for fodder. They are also responsible for overgrazing, one of the principal reasons for forest degradation. While this occurs throughout the year in the Terai, it is seasonal in high elevation pastures. About 40 percent of the high mountain forests have crown cover of less than 40 percent Acharya et al. 2012. •฀ Increasing demand for timber – the rapidly growing population places increasing demand on timber for building houses. People exploit timber far beyond their actual needs. In the central Himalayas about 70 m 3 of valuable wood are logged per house, although less than 20 m 3 would suffice if properly and efficiently used Mauch 1974. •฀ Invasive species – invasion of alien species has emerged as an important driver of forest degradation, particularly in the Terai and High Hills. Alien invasive species are proliferating and invading the natural environment leading to destruction and shrinkage of native flora and fauna. Many natural habitats have been degraded by species such as Mikania macrantha, Lantana camara, Parthenium spp. and Eichornia crassipes Paudel et al. 2007. Invasion and Land-use category Poorly-managed forest Poorly-managed sloping terraces Degraded rangelandopen land Area damaged by floods and landslides 1984-2003 Forest encroachment Total Degraded area million ha 2.100 0.290 0.647 0.106 0.119 3.262 Degraded land 36.03 10.00 37.00 0.72 2.04 28.24 Total land area million ha 5.828 2.969 1.750 11.551 5.828 11.551