A new article in Forest Ecology and Management reports the floristic composition and structure of sal (Shorea robusta) forests occupying a broad range of historical and environmental influences across an extensive range in the western Terai of Nepal. The article also explores anthropogenic and environmental factors that are responsible for variation among forest structure.
The study shows that fire and past disturbances are the important determinants of structure and composition of sal forest. Periodic fire is necessary for sal dominance, but too much burning adversely affects seedlings. For the long-term management of forests for both local livelihoods and biodiversity conservation, the study recommends further research on the effects of fire in the sal forest and adequate fire management policy addressing intensity, duration and timing.
Abstract: Sal (Shorea robusta) forest is found in an extensive array of conditions in lowland Nepal, and has been heavily used by both government and local people. Thus, we did a study to provide information on sal forests occupying a broad range of historical and environmental influences across an extensive range in the western Terai of previous termNepalnext term and explore factors - both environmental and anthropogenic - that may be responsible for variation of forest structure.
Trees, saplings, seedlings and shrubs were sampled along transects (2 km long) in two protected areas and two proposed community forests. The protected areas had three transects each, and a single transect covered two proposed community forests. Samplings were done every 200 m along the transects, a plotless technique sampled trees (>5 cm dbh). With tree sampling point as the center, shrubs and saplings (1-5 cm dbh and >1 m height) were sampled in 5 m radius circular plots and herbs and seedlings (<1 m height) were sampled in 1 m2 circular plots nested within shrub plots. Altogether 131 species were recorded: 28 trees, 10 shrubs, 6 climbers and 87 herbs. The mean density across all plots was 220 trees/ha and the average basal area was 13.2 m2/ha. Three different associations of sal forest were identified by cluster analysis. Community types distinguished in the classification analysis were clearly separated in the site ordination. None of the environmental variables measured (pH, percent organic matter, total nitrogen, available phosphorous, available potassium and soil texture) explained the distribution of plots in the site ordination. We concluded that rainfall and past disturbances (fire and anthropogenic use) are mainly responsible for different community types. Community types were different in structure and composition, thereby representing unique entities. The protection and maintenance of each of the different communities through forest management is important for biodiversity conservation.
Nilesh Timilsina, Michael S. Ross and Joel T. Heinen, A community analysis of sal (Shorea robusta) forests in the western Terai of Nepal, Forest Ecology and Management, Volume 241, Issues 1-3, 30 March 2007, Pages 223-234.