The Environmental Benefits
The real value of this tree in the Himalayan region has been its contribution to water management and soil erosion through its root and leaf litter systems.
In the past the leaf litter mass of the forest in undisturbed locations was up to half a metre deep. This prevented or slowed the annual monsoon rains rushing down the steep slopes and sweeping the topsoil away into the rivers below. The leaf litter allowed the rain to gently filter into the subsoil, recharging springs and maintaining the delicate balance of the ecosystem.
The Environmental Impact
With the forests gone, the rain’s impact on soil is no longer moderated by the water-absorbing layer of forest litter.
Locally called the “Banj”, the broad leafed oak is one of the most striking species in the entire Himalayan region. Sadly, in regions of lower Himalayas the very survival of this wonderful tree is under serious threat.
The Himalayan Evergreen Oak once covered hundreds of thousands of hectares of the lower Himalayas protecting the soil from the monsoon rains.
Several factors have contributed to the demise of the forests including:
- Cultivation of the steep slopes allowing precious topsoil to be gouged loose and swept into raging rivers
- Over-grazing of the forest floor preventing seedling regrowth
- Heavy cropping of the leaves of mature trees for cattle fodder stopping acorn production
- The ongoing pressure of population expansion
With the majority of the oaks gone, the springs have also gone and the trees have been replaced with grass. During the dry springs and long, hot summers, the region is now subject to serious water shortages and devastating grass fires. When the summer monsoon rains come, the erosion in these areas and consequent flooding downstream of the Himalayas is significant.
It has been predicted that some of the major rivers of India could be dry within the next 50 years if the snow fall continues to reduce.
The Indus, Ganges (Ganga), Yamuna which is the lifeline of Delhi, Brahmaputra and others such as the Sutlej, are all snow fed and originate in the Himalayas and the Tibetan Plateau.