The vegetation of Kashmir valley is broadly delimited into sixvegetational zones: blue pine, chir pine, deodar, fir, broad leaved and shrubtrees. Among the six vegetation zones pine forests constitute one of the most divergentand economically important species found in Kashmir Himalayas. They providevaluable natural resources which contribute significantly to the local andindustrial economy of the country and also protect the watersheds which sustainand regulate the water supply for the need of millions that inhabit Himalayanriver basins.
Pine forests being an important component of the Himalayanecosystem, demand for various pine tree products needs to be matched byincreased production to ensure their role in the environmental stability of theHimalaya. Pines are large group of evergreen resinous trees belonging to thefamily Pinaceae. Sahni (1990) reported 91 species, of which 7 species of pinesare indigenous to India. Out of these, 3 species occur in Kashmir region, viz.
, Pinuswallichiana A.B. Jackson, and P. roxburghiiSargent and P. halepensis Miller. P. wallichianacommonly known as blue pine is a tall (between 30 m and 50 m in height)straight evergreen tree.
It is found throughout the temperate regions of the KashmirHimalaya, ataltitudes of 1800–4300 m. (Dar and Dar, 2006). It is an importantcomponent of the middle and high altitude Himalayan forests.
Itpersists under moderate shade for many years but vigorous growth is attainedonly with complete overhead light. The winter snowfall acts beneficially inprotecting the seed on the ground from being devoured by birds. Years of amplesnowfall and rainfall are beneficial in preventing the mortality of seedling inthe forests. It regenerates most freely on newly exposed loose porous soil.
Itstimber is extensively used for a variety of purposes including construction,railway sleepers, bridges, paper pulp etc. (Dar and Dar, 2006). Itis also used for social and economic uplift of people living in mountainregions as well as for protection of steep slopes. The other two species ofpines i.e., P.
roxburghii and P. halepensis are uncommon in Kashmir Himalaya (Darand Dar, 2006). To meet the growing demand oftimber, various attempts have been made to replace uneconomic and slow growingtree species with the more useful and fast growing ones. Fire, fungi andinsects are the greatest agents of destruction to our forests. All parts oftrees, from roots to twigs, buds and leaves, flowers, and heartwood, aresusceptible to insect attack. Some insects prefer saplings and young trees,some attack older ones, others infest unhealthy and dying trees, still othersprefer dead material, while some attack only rotten wood. Yet another categoryof these insects select seasoned or processed wood for feeding and breeding.Bark beetles are economically importantpests both on conifer forests and broad-leaved tree species in the temperateregions of the northern hemisphere.
The Himalayan species attack mainly livingtrees or infest freshly felled logs in the pure or mixed conifer forests(Schmutzenhofer, 1988; Tshering & Chhetri, 2000). The tree species infestedby the beetle pests may be recognized at a distance by observing leaves whichare initially light green then to light straw and eventually to yellowish-brownin colour. Close observation of the infested tree may show a fine reddish-brownboring dust in bark cervices and at the base.Significant endeavors have beencarried out to determine the causes of bark beetle outbreaks. The most possibleexplanation is that, beetle outbreaks occur when there is an abundance ofbreeding material especially freshly felled logs suitable for beetlereproduction (Raffa and Berryman, 1983; Christiansen and Bakke, 1988).
Barkbeetles attract conspecifics by emitting pheromones, resulting heavyinfestations and eventually death of the colonized tree. Healthy trees mayproduce secondary metabolites which contain a number of insecticidal andfungicidal compounds that can kill or injure attacking beetles. However underoutbreak conditions, the beetles can also attack standing vigorous trees whichcan be disastrous for the ecosystem stability at regional scale. Barkbeetles play key roles in the structure of natural plant communities andlarge-scale biomes. They contribute to nutrient cycling, canopy thinning, gapdynamics, biodiversity, soil structure, hydrology, disturbance regimes, andsuccessional pathways. Several species in particular can genuinely bedesignated “landscape engineers,” in that