Final answer:
Nepal's natural vegetation ranges from tropical forests in the Terai lowlands to alpine flora in the Himalayas, with biodiversity threatened by deforestation and soil erosion.
Step-by-step explanation:
The distribution of natural vegetation in Nepal is largely influenced by the country's unique topography, which includes the Himalayan Mountains to the north and the Terai lowlands in the south. The forests of Nepal can be categorized into several types: tropical, subtropical, temperate, subalpine, and alpine, each occurring at different altitudes and accommodating distinct types of vegetation and biodiversity.
In the Terai lowlands of southern Nepal, one can find tropical monsoon forests and grasslands, which offer fertile farmland. Moving northwards, subtropical forests are prevalent in the Mahabharat Lekh and Siwalik Hills. These forests consist of species such as sal (Shorea robusta), chir pine (Pinus roxburghii), and various broadleaved deciduous trees. As one ascends to the mid-hills, temperate forests dominate, harboring oak, rhododendron, and various conifer species. High altitude areas, especially above the timberline, are characterized by subalpine and alpine vegetation, with shrubs, dwarf trees, and meadows that become sparse as one approaches the snow line.
Nepal's rich biodiversity is threatened by severe deforestation and soil erosion, principally due to tree cutting for firewood, building materials, and agricultural expansion. Efforts to protect and manage the natural vegetation are crucial for the country's environmental health and the sustainability of its agricultural and tourism economies.