Sal Heartwood Borer
Context
- The Madhya Pradesh Forest Department has sought approval to remove nearly 1.5 lakh sal trees in Dindori district after a large-scale outbreak of the Sal Heartwood Borer.
- Under Section 2 of the Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980, prior approval of the Central Government is mandatory for activities such as de-reservation of forests, diversion of forest land for non-forest purposes, assignment of forest land on lease, and clear felling.
About Sal Heartwood Borer
- The Sal Heartwood Borer is a dark-brown longhorn beetle regarded as the most destructive insect pest of sal forests in South Asia.
- It primarily attacks mature sal trees with a girth exceeding 20 cm.
Nature of Damage
- The larvae tunnel deep into the heartwood, disrupting the movement of nutrients within the tree.
- Affected trees exhibit browning of the crown, while sawdust-like frass accumulates around the base of the trunk.
- Infestation outbreaks generally follow an approximately 30 year epidemic cycle.
- As a control measure, selected infested trees are felled after bruising the bark, which releases sap that attracts the beetles.
Sal Tree (Shorea robusta)
Key Features
- Sal (Shorea robusta) is a large, slow- to moderately-growing deciduous hardwood native to the Indian subcontinent and commonly occurs in dense, gregarious stands.
- It sheds most of its leaves during the dry spring season and produces new foliage in April–May.
- When injured, the trunk exudes an aromatic resin known as ral or dammar, which solidifies on exposure to air.
Habitat & Distribution
- Preferred Conditions: Well-drained sandy-loam soils with moderate to high rainfall.
- Distribution: Found in tropical moist and dry deciduous forests, especially across the Sub-Himalayan region and the Central Indian Plateau, including Madhya Pradesh, Chhattisgarh, Odisha, Jharkhand, and West Bengal.
Economic Importance
- The timber is heavy, coarse-grained, durable, and naturally resistant to termites because of its high resin content.
- Widely used in construction, railway sleepers, bridge piles, and shipbuilding.
- The resin is used for traditional medicine, incense (dhup), and boat caulking.
- Seeds yield edible oil, which is used in cooking, cosmetics, and as a substitute for cocoa butter in the chocolate industry.
Status
- Sal is the State Tree of Chhattisgarh and Jharkhand.
- Its leaves, seeds, and resin are recognised as Minor Forest Produce (MFP) under the Forest Rights Act, 2006.