Influence of Type and Depth of Bark Incision on Gum Yield and Bark Recovery in Lannea coromandelica

Gum tapping from forest trees played a vital role in supporting both rural livelihoods and a multiple of industries in India. Lannea coromandelica produces commercial gum called Jhingan and is commonly found in the moist and dry deciduous forests. In order to explore and understand how different methods of making cuts in the bark as well as varying cut depths on gum yield and bark recovery in L. coromandelica, a field study was conducted at Sirsi, Karnataka. Healthy trees were selected for the experiment and each was subjected to four types of bark incisions like notch, vertical, horizontal and slant cut, with four different depths: 0.5, 0.75, 1.0, and 1.5 cm. The horizontal cuts led to the highest gum yield (1520.7 g/m²), closely followed by notch cuts (1423.6 g/m²). In contrast, vertical and slant cuts produced significantly less gum yield. This species bark is thicker, hence deeper cuts, especially those at 1.5 cm, gave the highest gum output (1653.6 g/m²) with faster bark recovery (72%). The vertical and horizontal incisions allowed the best bark recovery (70% and 69%, respectively); while shallowest depth (i.e., 0.5 cm and 1.0 cm) showed the lowest bark regeneration rate (<50%). These findings suggest that while deeper, horizontally placed cuts in L. coromandelica can maximize gum extraction, and also increases the risk of long-term damage to the tree.