The and rainfall are beneficial in preventing the

The vegetation of Kashmir valley is broadly delimited into six
vegetational zones: blue pine, chir pine, deodar, fir, broad leaved and shrub
trees. Among the six vegetation zones pine forests constitute one of the most divergent
and economically important species found in Kashmir Himalayas. They provide
valuable natural resources which contribute significantly to the local and
industrial economy of the country and also protect the watersheds which sustain
and regulate the water supply for the need of millions that inhabit Himalayan
river basins. Pine forests being an important component of the Himalayan
ecosystem, demand for various pine tree products needs to be matched by
increased production to ensure their role in the environmental stability of the
Himalaya.  

Pines are large group of evergreen resinous trees belonging to the
family Pinaceae. Sahni (1990) reported 91 species, of which 7 species of pines
are indigenous to India. Out of these, 3 species occur in Kashmir region, viz., Pinus
wallichiana A.B. Jackson, and P. roxburghii
Sargent and P. halepensis Miller. P. wallichiana
commonly 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 Kashmir
Himalaya, at
altitudes of 1800–4300 m. (Dar and Dar, 2006). It is an important
component of the middle and high altitude Himalayan forests. It
persists under moderate shade for many years but vigorous growth is attained
only with complete overhead light. The winter snowfall acts beneficially in
protecting the seed on the ground from being devoured by birds. Years of ample
snowfall and rainfall are beneficial in preventing the mortality of seedling in
the forests. It regenerates most freely on newly exposed loose porous soil. Its
timber is extensively used for a variety of purposes including construction,
railway sleepers, bridges, paper pulp etc. (Dar and Dar, 2006). It
is also used for social and economic uplift of people living in mountain
regions as well as for protection of steep slopes. The other two species of
pines i.e., P. roxburghii and P. halepensis are uncommon in Kashmir Himalaya (Dar
and Dar, 2006).

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To meet the growing demand of
timber, various attempts have been made to replace uneconomic and slow growing
tree species with the more useful and fast growing ones. Fire, fungi and
insects are the greatest agents of destruction to our forests. All parts of
trees, from roots to twigs, buds and leaves, flowers, and heartwood, are
susceptible to insect attack. Some insects prefer saplings and young trees,
some attack older ones, others infest unhealthy and dying trees, still others
prefer dead material, while some attack only rotten wood. Yet another category
of these insects select seasoned or processed wood for feeding and breeding.

Bark beetles are economically important
pests both on conifer forests and broad-leaved tree species in the temperate
regions of the northern hemisphere. The Himalayan species attack mainly living
trees or infest freshly felled logs in the pure or mixed conifer forests
(Schmutzenhofer, 1988; Tshering & Chhetri, 2000). The tree species infested
by the beetle pests may be recognized at a distance by observing leaves which
are initially light green then to light straw and eventually to yellowish-brown
in colour. Close observation of the infested tree may show a fine reddish-brown
boring dust in bark cervices and at the base.

Significant endeavors have been
carried out to determine the causes of bark beetle outbreaks. The most possible
explanation is that, beetle outbreaks occur when there is an abundance of
breeding material especially freshly felled logs suitable for beetle
reproduction (Raffa and Berryman, 1983; Christiansen and Bakke, 1988). Bark
beetles attract conspecifics by emitting pheromones, resulting heavy
infestations and eventually death of the colonized tree. Healthy trees may
produce secondary metabolites which contain a number of insecticidal and
fungicidal compounds that can kill or injure attacking beetles. However under
outbreak conditions, the beetles can also attack standing vigorous trees which
can be disastrous for the ecosystem stability at regional scale.

 Bark
beetles play key roles in the structure of natural plant communities and
large-scale biomes. They contribute to nutrient cycling, canopy thinning, gap
dynamics, biodiversity, soil structure, hydrology, disturbance regimes, and
successional pathways. Several species in particular can genuinely be
designated “landscape engineers,” in that

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