A research team found that tree felling and timber extraction produce different damage patterns in Sal (Shorea robusta)-dominated forests. Extraction caused the greatest share of seedling damage, while felling more often harmed residual trees. Seedlings were commonly bent, whereas standing trees sustained crown or lower-stem injuries. Although most damage was mild, routine harvesting may still weaken regeneration and future forest development. The findings can inform reduced-impact logging, operator training, extraction-route planning, and ecological monitoring, helping managers meet timber needs while protecting the long-term productivity and resilience of Sal forest ecosystems.
Timber harvesting is essential to forest management and rural livelihoods, but falling trees, dragged logs, machinery, and repeated traffic can injure vegetation left within harvested stands. International studies have linked such operations to damage ranging from broken branches and stems to uprooting and injuries near tree bases. These effects may reduce tree growth, carbon storage, timber value, and the survival of natural regeneration. In Nepal, previous research on managed Sal forests has mainly examined regeneration, species diversity, soils, carbon stocks, and timber losses. Far less is known about which harvesting operations produce particular injuries, which plant groups are most vulnerable, and how severe the resulting damage is, limiting the development of targeted mitigation measures.
A study (DOI: 10.48130/aee-0026-0012 ) published in Agricultural Ecology and Environment on 20 May 2026 by Rajeev Joshi's team, Agriculture and Forestry University, reports that extraction caused the largest share of seedling damage, while felling primarily affected residual trees and produced operation-specific patterns of injury.
The researchers conducted field assessments in Saraswati Community Forest and Belakatari National Forest in Udayapur District, Nepal. To examine felling-related effects, they established 30 circular plots, each centered on a tree previously marked for harvesting. The plot radius corresponded to the height of the selected tree, allowing the researchers to cover its likely impact area. Ten plots were located in the community forest and 20 in the national forest. Before harvesting, the team visually inspected vegetation in the predicted direction of fall so that newly created injuries could be distinguished from pre-existing damage. After felling, they recorded affected trees and seedlings and classified injuries by type and severity. To evaluate timber extraction, the researchers established 30 transects along skid trails between tree stumps and nearby forest roads. Each transect extended up to approximately 60 meters and covered a 12-meter-wide corridor. All residual plants within these corridors were inventoried. Damage was categorized as bending, crown damage, stem damage, uprooting, or butt-end damage. Severity was rated as low, medium, or high using predefined criteria and assessments standardized among field-team members. Percentages and 95% confidence intervals were then calculated using the Wilson score method. Extraction accounted for 45.41% of recorded seedling damage, compared with 43.35% from felling and 11.24% from other human activities. In contrast, 58.06% of damage to residual trees resulted from felling, compared with 22.58% from extraction. During felling, 44.4% of damaged seedlings were bent, 38.4% sustained stem damage, and 17.2% were uprooted. Crown injury accounted for 61.1% of damaged residual trees. During extraction, bending affected 47.1% of damaged seedlings, while 29.6% sustained stem damage and 23.3% were uprooted. Butt-end injury accounted for 71.4% of damage to residual trees during extraction. Most tree injuries were low severity, but 53.4% of seedling injuries during extraction were medium or high severity, highlighting the vulnerability of forest regeneration to machinery and dragged logs.
Overall, the study provides the first diagnostic assessment of harvesting-related damage to residual plants in Nepalese forestry. Findings support pre-harvest inventories, directional felling, planned skid trails, fewer machinery passes, post-harvest monitoring, improved operator training, and ecological damage records. Because it identified damage patterns rather than stand-wide incidence, broader pre- and post-harvest inventories remain necessary. Nevertheless, the evidence gives forest offices and community groups a practical basis for protecting seedlings and residual trees while supporting sustainable timber production across Nepal's managed Sal forests.
