A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period ...A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period and to analyze heterogeneity of regeneration in relationship to topographic slope and incidence of light in Chacocente Wildlife Reserve in Nicaragua. Permanent sample plots were established in 2001, and all individuals with height as low as 10 cm and diameter as large as 10 cm were recorded for three consecutive years from 2001 to 2003. The results show that the density of naturally regenerated individuals varied significantly among species, as well as over time. L. minimiflorus and T. ochracea had higher densities compared with L. divaricatum, and the net change in population density was slightly positive for T. ochracea only. Regeneration was more abundant in the gentle and steep slopes under partial exposure of the crown to sunlight, thus resulting in aggregated pattern of distribution, especially for L. minimiflorus and T. ochracea. We concluded that natural regeneration alone is not sufficient to maintain the desired number of stocks of these species, and an immediate restoration measure should be taken to assist the natural regeneration process.展开更多
There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. ...There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. Using tree biomass as proxy for degradation, we assessed the current state of biomass within dominant land use types and examined its implications for sustainability. The highest above-ground mean tree biomass density of 1158 t·ha-1 was recorded for the reserved forest followed by 728, 13, 11, 8, 5 and 3 t·ha-1in the protected forest, fallow land, cultivated-unirrigated land, grassland, orchard land and cultivated-irrigated land respectively. Of the total ac- cessible biomass, only 0.31% was extracted annually by the local people for fuel, fodder and other uses. Though, the current level of ex- traction may be sustainable in the short run, insufficient regeneration is observed for long term sustainability. Forest biomass production was simulated for the next 30 years with a logistic growth model and the relative significance of input variables in influencing system be- haviour was analysed through sensitivity analysis. The model results highlighted the declining forest resources in the long run. Positive response through appropriate government policies can, however, change the scenario for the better.展开更多
The study focuses on the dynamics and biomass production （g·m-2） of understory （herbaceous） plant community under broad-leaf forests consisting of Quercus leucotrichophora （Banj-oak）, Quercus floribunda （T...The study focuses on the dynamics and biomass production （g·m-2） of understory （herbaceous） plant community under broad-leaf forests consisting of Quercus leucotrichophora （Banj-oak）, Quercus floribunda （Tilonj-oak） and Quercus semicarpifolia （Kharsu-oak）, respectively in central Himalaya, India. With increasing altitudes, the den-sity and biomass decreased significantly across the three types of forests. Banj-oak forest harboured the maximum density and biomass among the other sampling sites. The mean density of herb species in two contrasting orientation differed significantly （p0.05）, showing relatively higher density on slope orientation （west）. Across the sites, total production declined significantly with increasing altitude of the sites （p0.05）, and Banj-oak forest presented the highest production.展开更多
The natural regeneration of the tree species in pure natural forest stand and enrichment plantations of Baraitali Forest of Chittagong (South) Forest Division, Bangladesh was studied by stratified random quadrat metho...The natural regeneration of the tree species in pure natural forest stand and enrichment plantations of Baraitali Forest of Chittagong (South) Forest Division, Bangladesh was studied by stratified random quadrat method during April 2002 to November 2002. Totally 100 plots of 3 m X 3 m in size represents a total of 64 regenerating tree species from natural forest with an average seedlings of 24767/hm2, while only 40 regenerating tree species were recorded from enrichment plan-tations with an average seedlings of 18633/hm2. Maximum regeneration in natural forest was found with Castanopsis spp. (2200 seedlings/hm2) followed by Glochidion lanceolarium (2183 /hm2) whereas, in enrichment plantations maximum regen-eration was found with Dipterocarpus gracilis (2117/hm2) followed by Anogeissus acuminata (2000/hm2). For natural forest, highest relative density was found for Castanopsis spp (8.88%), relative frequency for Glochidion lanceolarium (7.36%), rela-tive abundance for Syzygium spp. (3.79%) and Importance Value Index were recorded with Glochidion lanceolarium (18.24%). The corresponding values for enrichment plantations were highest with Dipterocarpus gracilis (11.36%), Glochidion lanceo-larium (9.71%), Dipterocarpus gracilis (5.92%), Glochidion lanceolarium (23.32%) respectively. Stem per hectare of some common trees with their seedlings and saplings in both the natural stands and enrichment plantations showed that only Dip-terocarpus gracilis successfully recruited in both sites but recruitment was higher in natural forest. Like many other primary rain forests, the Baraitoli forest typically has both substantial seedlings and soil seed bank from which regeneration may occur. The naturally regenerated seedlings are quite dense but it could not reach the pole stage due to human interference.展开更多
基金supported by the Swedish International Development Agency (Sida)
文摘A study was conducted to examine the natural regeneration of three dry forest species, Lysiloma divaricatum （Jacq.）, Tabebuia ochracea （Cham.） and Lonchocarpus minimiflorus （Donn. Sin.） over a three-year period and to analyze heterogeneity of regeneration in relationship to topographic slope and incidence of light in Chacocente Wildlife Reserve in Nicaragua. Permanent sample plots were established in 2001, and all individuals with height as low as 10 cm and diameter as large as 10 cm were recorded for three consecutive years from 2001 to 2003. The results show that the density of naturally regenerated individuals varied significantly among species, as well as over time. L. minimiflorus and T. ochracea had higher densities compared with L. divaricatum, and the net change in population density was slightly positive for T. ochracea only. Regeneration was more abundant in the gentle and steep slopes under partial exposure of the crown to sunlight, thus resulting in aggregated pattern of distribution, especially for L. minimiflorus and T. ochracea. We concluded that natural regeneration alone is not sufficient to maintain the desired number of stocks of these species, and an immediate restoration measure should be taken to assist the natural regeneration process.
基金Norwegian University of life sciences,Aas,Norway (Sub Project Number 1526010,Main Project No 11526010)the Integrated Institute of Himalayan Studies (UGC Centre of Excellence),Shimla,India (Project Number 9-3/2005)
文摘There is enough evidence to show that the forest biomass has decreased significantly in the Indian Himalayan state of Himachal Pradesh. The government has responded through restrictive measures to check this decline. Using tree biomass as proxy for degradation, we assessed the current state of biomass within dominant land use types and examined its implications for sustainability. The highest above-ground mean tree biomass density of 1158 t·ha-1 was recorded for the reserved forest followed by 728, 13, 11, 8, 5 and 3 t·ha-1in the protected forest, fallow land, cultivated-unirrigated land, grassland, orchard land and cultivated-irrigated land respectively. Of the total ac- cessible biomass, only 0.31% was extracted annually by the local people for fuel, fodder and other uses. Though, the current level of ex- traction may be sustainable in the short run, insufficient regeneration is observed for long term sustainability. Forest biomass production was simulated for the next 30 years with a logistic growth model and the relative significance of input variables in influencing system be- haviour was analysed through sensitivity analysis. The model results highlighted the declining forest resources in the long run. Positive response through appropriate government policies can, however, change the scenario for the better.
文摘The study focuses on the dynamics and biomass production （g·m-2） of understory （herbaceous） plant community under broad-leaf forests consisting of Quercus leucotrichophora （Banj-oak）, Quercus floribunda （Tilonj-oak） and Quercus semicarpifolia （Kharsu-oak）, respectively in central Himalaya, India. With increasing altitudes, the den-sity and biomass decreased significantly across the three types of forests. Banj-oak forest harboured the maximum density and biomass among the other sampling sites. The mean density of herb species in two contrasting orientation differed significantly （p0.05）, showing relatively higher density on slope orientation （west）. Across the sites, total production declined significantly with increasing altitude of the sites （p0.05）, and Banj-oak forest presented the highest production.
文摘The natural regeneration of the tree species in pure natural forest stand and enrichment plantations of Baraitali Forest of Chittagong (South) Forest Division, Bangladesh was studied by stratified random quadrat method during April 2002 to November 2002. Totally 100 plots of 3 m X 3 m in size represents a total of 64 regenerating tree species from natural forest with an average seedlings of 24767/hm2, while only 40 regenerating tree species were recorded from enrichment plan-tations with an average seedlings of 18633/hm2. Maximum regeneration in natural forest was found with Castanopsis spp. (2200 seedlings/hm2) followed by Glochidion lanceolarium (2183 /hm2) whereas, in enrichment plantations maximum regen-eration was found with Dipterocarpus gracilis (2117/hm2) followed by Anogeissus acuminata (2000/hm2). For natural forest, highest relative density was found for Castanopsis spp (8.88%), relative frequency for Glochidion lanceolarium (7.36%), rela-tive abundance for Syzygium spp. (3.79%) and Importance Value Index were recorded with Glochidion lanceolarium (18.24%). The corresponding values for enrichment plantations were highest with Dipterocarpus gracilis (11.36%), Glochidion lanceo-larium (9.71%), Dipterocarpus gracilis (5.92%), Glochidion lanceolarium (23.32%) respectively. Stem per hectare of some common trees with their seedlings and saplings in both the natural stands and enrichment plantations showed that only Dip-terocarpus gracilis successfully recruited in both sites but recruitment was higher in natural forest. Like many other primary rain forests, the Baraitoli forest typically has both substantial seedlings and soil seed bank from which regeneration may occur. The naturally regenerated seedlings are quite dense but it could not reach the pole stage due to human interference.
