Stump Dimensions and Timber Loss in Harvested Sal Forests of Nepal

Timber harvesting is the main component of sustainable forest management as the efficiency of timber harvesting directly affects wood recovery and economic returns based on stump dimension. This paper investigates the relationship between stump size (diameter and height, diameter at breast height (DBH), and timber volume in Sal (Shorea robusta) forests of the Western Terai region of Nepal. The study measured 1,623 trees before and after felling. DBH and tree height for all standing trees were measured before felling while stump diameter and stump height (upper and lower cuts) were measured after felling. Regression and post-hoc tests were used to analyze the relationship and differences among classes. The results indicate a higher stump height than the standard recommendation (15 cm), resulting in timber losses. On average, stump volume contributed 7.19% to the timber volume. Class I trees had significantly higher stump height and volume than lower classes, but percentage volume loss was the highest in lower-class trees. DBH was found to be a strong positive predictor of stump volume (R² = 0.741), while tree height was not found significant predictor. Moreover, stump diameter was found to be a strong predictor of DBH (R² = 0.999). The results show that systematic timber losses occur due to excessive stump heights and that stump-based models can be used for post-harvest monitoring and illegal logging detection. Improving felling techniques to maintain recommended stump height standards can contribute to increase timber recovery and harvesting efficiency in Sal forests of Nepal.