Wildland fires and moist deciduous forests of Chhattisgarh, India: divergent component assessment

We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected areas during pre and post-fire seasons, （2） to evaluate vegetation struc- ture and diversity by layer in the four fire frequency zones, （3） to evalu- ate the impact of fire frequency on the structure of economically impor- tant tree species of the region, and （4） to quantify fuel loads by fire fre- quency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low- frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class （A） and saplings of size class （B）, represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sis- soo after fire, whereas intermediate-aged trees were more abundant pre- fire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The netchange in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, how- ever, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest manage- ment. Use of controlled fire, fire lines and mapping of fire prone areas are fundamental principles of fire hazard reduction in these areas.

Changes in soil biochemical properties following replacement of Banj oak forest with Chir pine in Central Himalaya,India

Introduction:In Central Himalaya,anthropogenic activities have led to the widespread replacement of Banj oak(Quercus leucotrichophora)forest by Chir pine(Pinus roxburghii)for decades.This study was conducted to determine how natural Banj oak,Chir pine,and mixed oak-pine forest would differ in soil microbial biomass and soil nutrients.Soil microbial biomass nitrogen(SMBN)and phosphorus(SMBP),soil organic carbon(SOC)total nitrogen(TN),and total phosphorus(TP)in the 0 to 15 cm soil layer were investigated in the Central Himalayan region in the stands of Banj oak,mixed oak-pine,and Chir pine forest.Results:The SMBN and SMBP were significantly higher in Banj oak and mixed oak-pine forest as compared to Chir pine forest.The ratios of SMBN to TN(SMBN/TN)and SMBP to TP(SMBP/TP)were significantly higher in the Chir pine forest,indicating that in this forest,the proportion of microbial biomass N and P to total soil N and P was higher as compared to Banj oak forest.A similar pattern of variation was found in relation to season across the forests,all with an apparent peak in the rainy season.Conclusion:These results indicate that low microbial biomass N and P may be one of the reasons to create a nutrient poor site in Chir pine forest.The collection of pine litter by local people also impairs the return of nutrients to the soil and makes it difficult for Banj oak to re-invade areas occupied by Chir pine.This calls for cautions in large-scale conversions of the Banj oak forests to coniferous plantations as a forest management practice on concerns of sustaining soil productivity.