Rishikesh, April 2 The Uttarakhand government has sought permission from the Union environment ministry to cut down over 19,000 Sal trees within the Dehradun Forest Division that have been damaged by the larvae of Sal borers, and to conduct a "Tree Trap Operation," said the state's Forest Minister Subodh Uniyal.
After receiving reports regarding an infestation of Sal borer (Hoplocerambyx spinicornis) larvae—a pest for Sal trees—in the Thano, Asarori, and Jhajra ranges of the forest division, the Forest Department contacted the Forest Research Institute (FRI), he said.
Subsequently, an expert team from the FRI identified 19,170 Sal trees as being affected by the larvae. The forest minister noted that some of these trees have withered right up to their canopy level and will therefore need to be felled.
A "Tree Trap Operation" will be conducted on the remaining trees during the monsoon season. According to experts, Hoplo larvae bore into the roots of Sal trees and tunnel through the xylem (the tissue responsible for transporting water and mineral salts absorbed by the roots to various parts of the plant) located within the trunk, thereby hollowing out the tree from the inside. Consequently, the trees eventually wither and die.
In a "Tree Trap Operation," a few healthy Sal trees are felled and cut into four-foot-long logs, which are then placed in rainwater. The scent emanating from these Sal logs attracts the Hoplo insects. These insects are then captured using tweezers and dropped into kerosene, which kills them. This is a large-scale operation that frequently utilises the assistance of women's self-help groups.
According to experts, the fact that such a large number of trees in the Forest Division have been affected by the "Hoplo" pest is a matter of grave concern from the perspective of ecological balance.
They noted that the pest serves as a natural food source for woodpeckers and hence helps prevent attacks on Sal trees.
An "Hoplo" pest infestation previously occurred in the Thano Range of the forest division during the early 1990s.
Experts also question if disruption in the local ecosystem or the effects of climate change may have played a role in the extensive damage to Sal trees. Uttarakhand experienced exceptionally heavy rainfall last year, and according to experts, excessive precipitation is considered to be one of several factors responsible for the "Hoplo" infestation.
The minister, too, emphasised the need for a comprehensive scientific study to investigate the causes behind the "Hoplo" outbreak and to identify potential solutions.