Response of understorey vegetation in chir pine forests to prescribed burning in Shiwalik region of Himalaya

Abstract

Aim: The present investigation was carried out to understand the impact of controlled/prescribed burning on understorey vegetation in chir pine (Pinus roxburghii) forests of Shiwalik region to manage the summer fire damage. Methodology: Chir pine forest areas of two hectares (ha) each were selected at three sites in Shiwalik region of Himalaya for prescribed burning. Each forest area was delineated into three plots of which one plot was burnt during mid-winter in the year 2017 (B1) and another plot burnt twice (B2) during 2017 and 2018 whereas the third was kept unburnt plot (C) in each site. The phytosociological attributes of understorey vegetation were studied in November, 2018. The difference in density of shrubs (plants 25 m-2) and herbs (plants m-2) in unburnt (C), once burnt (B1) and twice burnt (B2) was analyzed through critical difference (CD). Results: Total density (plants 25m-2) of shrubs ranged from 7.15 to 12.95 in unburnt (C), 3.90 to 8.40 in once burnt (B1) and 2.25 to 4.65 in twice burnt (B2) plots whereas total density (plants m-2) of herbs varied from 25.83 to 44.95 in unburnt (C), 33.20 to 75.92 in once burnt (B1) and 29.31 to 90.93 in twice burnt (B2) plots. The density of shrubs was significantly higher in unburnt plots (C) as compared to burnt plots and vice versa for herbs. The Shanonn Wiener Index (H) ranged from 1.76 to 2.39 for shrubs and 2.32 to 3.15 for herbs. Interpretation: The density of herbs was higher in burnt plots and it was vice versa for shrubs. The prescribed burning enhanced diversity of herbs while shrubs diversity decreased with burning.