Impact of Fire on Plant Diversity, Regeneration, and Carbon Stock in Community Forests at Lamahi, Dang, Nepal

Abstract

This study investigated the effects of fire on plant species diversity, biomass, and regeneration at Bakena and Sundabari Community Forests, Lamahi, Dang, Nepal. Altogether 30 quadrats that experienced burnt (Sundabari CF) and 30 quadrats that were not exposed to fire (Bakena CF) were laid for the study. A total of 69 plant species, under 32 families, were recorded in this study from the unburnt Bakena Community forest (BCF), whereas 52 plant species, under 27 families were recorded from burnt Sundabari Community forest (SCF). Among these recorded species, 35 species were herbs, 20 species were trees and 14 species were shrubs in the unburnt forest (BCF), whereas in SCF that experienced fire every year had 22 species of herbs, 16 species of shrubs, and 14 species of trees. Tree species like Bombax ceiba, Ficus benjamina, Ficus racemosa, Madhuca longifolia, Mallotus philippenis, Phyllanthu emblica, etc were not recorded in the SCF that were having a fire every year. Similarly, the shrubs like Jasmine sp. Senna occidental, Smilax sp. and Thysanolaena latifolia and herbs like Acmella paniculata, Acorus sp., Ageratum houstonianum, Anaphalis sp., Asplenium sp., etc were not recorded from the SCF (burnt forest). Some of the shrubs and herbs recorded in burnt forest (BF) but absent at unburnt forest (UBF) were Asparagus racemosa, Dioscorea deltoidea, Phyllanthus sp., Nyctanthes arbor-tristis, Adiantum sp., Digitaria sanguinalis, Eulaliopsis binate, Galinsoga sp., etc. The Shannon Weiner diversity index and Simpson diversity index were higher in the non-fire forest (BCF). In the present study, the total density of seedlings, saplings, and trees of all species in UBF were 474.167, 694.167, and 559.167 individuals/ha, respectively whereas in BF seedlings, saplings, and trees were found to be 552.5, 565.83, and 341.667 individuals/ha, respectively. The density of seedlings of Shorea robusta, saplings of Melia azedarach, and trees of Acacia catechu, were found to be higher than other species in BCF i.e unburnt forest. But at SCF, that experience fire every year had the higher density of Acacia catechu seedlings, saplings, and trees than other species. Total Carbon stock in UBF was much higher than at the BF. The total carbon stock in trees of UBF and BF was calculated to be 123.690 t/ha, and 23.133 t/ha respectively. Shorea robusta had the highest biomass in both above and below ground in both forests i.e 72.293 t/ha in above ground and 14.459 t/ha in below ground in NFF (BCF) and 20.439 t/ha above ground and 4.088 t/ha below ground in FF (SCF). Soil organic carbon decreased after a fire. The % of mineralizable N, available P, and extractable K decreased at FF (i.e SCF) but the bulk density increased at the FF (at SCF).