The vegetation of Central Karakorum National Park covers only a small percentage of the park area (14.7%). High elevation, coldness, and the rough topography, indeed, restrict the area suitable for plants establishment. In particular, temperature is a limiting factor at higher elevations (above 4500 m) while insufficient water availability during the growing season is impeding plants growth at lower altitudes (below 2000 m, where natural vegetation is mainly found around water bodies as streams or lakes). Additionally, vegetation has been affected by the millennium-old human and livestock presence. Nevertheless, different vegetation types grow in the CKNP and they are of major importance both for ecological reasons (e.g. as habitat for wildlife, biodiversity conservation) and for the sustainment of local communities (e.g. for the provision of grazing ground, firewood, timber). Additionally environmental services like protection from soil erosion, regulation of water quantity and quality, nutrient recycling are being provided.
The plant communities present in Central Karakorum National Park are of particularly interest since the park location in the transition zone between sub-tropical humid condition to the south and continental dry climate of northern areas. Indeed, inside the CKNP borders, this transition is evident moving from southwest towards northeast. CKNP can therefore ideally be divided into two main ecological zones: a southwest part, around Gilgit district, which is relatively warmer and partially influenced by the summer monsoon and the northeast part, felling mostly in Skardu district which is characterized by a more continental climate (Treydte et al., 2006). This climate patterns have a major influence on vegetation characteristics and distribution: it is of particularly interest to deeply evaluate the effect of climate transition on the CKNP forest resources, especially for their importance in the livelihoods of local communities. Overall, the South-Western sector is characterized by a forest composition and structure which is richer both in area, biomass and species. Most of the largest forest of CKNP are located in the Southern lateral valleys of the main Gilgit river valley (with few exceptions on the southern border of CKNP along Indus river).
Good examples of those rich forest ecosystems can be found in Haramosh, Khaltaro, Bagrote, Jaglot Gor and Astak valleys among others. On the contrary, in the North-Eastern valleys, mainly plant adapted to cold and xeric environment can be found. Forest cover is more fragmented and sparse with lower densities, stand biomass and increments. Forests areas here are therefore more scattered.
Vegetation types, which partially follow the classification proposed by Champion et al. (1965), have been formulated according to the species composition and, therefore, as a consequence of the most prominent ecological processes shaping their geographic distribution. Overall, inside the CKNP limits 4 forests and 3 shrub-lands types can be recognized.
Starting from the valley bottom and gradually increasing altitude the following vegetation belts can be found:
The forests inside the CKNP have been classified into 3 broad categories sparse trees, open forest and closed forest
Sparse trees vegetation
It’s a class with a reduced tree cover (<10%) which therefore cannot be classified as a forest according to FAO standards. The tree individuals are sparse and small (<5 m), often Junipers or heavily degraded mountain dry temperate coniferous forests.
It’s the first classification of forest. Can be the result of the degradation of a closed forest or a forest growing on poor soil. The vegetation cover is between 10 and 50% and the mean height of tallest trees is between 5 and 15 m. In this category are included the forest which might be managed in the future and in which reforestation is suggested. The species composition can be various, from degraded spruce (Picea smithiana) and Pine (Pinus wallichiana) to dense Juniperus woodland.
It’s the category which includes the most productive forests. The vegetation cover is above 50% and the mean height of tallest trees it’s above 15 m. The sustainable forest management will be applied mostly to this category. Usually this class is composed by dense forests of spruce (Picea smithiana), pine (Pinus wallichiana) and/or birch (Betula utilis). This category have the highest biomass and increment.
For each class of vegetation the average biomass and increment have been calculated (Anfodillo et al., 2009).