Biometric inventories for 25 years,from 1983 to 2005,indicated that the Jianfengling tropical mountain rain forest in Hainan,China,was either a source or a modest sink of carbon.Overall,this forest was a small carbon ...Biometric inventories for 25 years,from 1983 to 2005,indicated that the Jianfengling tropical mountain rain forest in Hainan,China,was either a source or a modest sink of carbon.Overall,this forest was a small carbon sink with an accumulation rate of(0.56±0.22) Mg C ha-1yr-1,integrated from the long-term measurement data of two plots(P9201 and P8302).These findings were similar to those for African and American rain forests((0.62±0.23) Mg C ha-1yr-1).The carbon density varied between(201.43±29.38) Mg C ha-1 and(229.16±39.2) Mg C ha-1,and averaged(214.17±32.42) Mg C ha-1 for plot P9201.Plot P8302,however,varied between(223.95±45.92) Mg C ha-1 and(254.85±48.86) Mg C ha-1,and averaged(243.35±47.64) Mg C ha-1.Quadratic relationships were found between the strength of carbon sequestration and heavy rainstorms and dry months.Precipitation and evapotranspiration are two major factors controlling carbon sequestration in the tropical mountain rain forest.展开更多
Aims Soil respiration is one of the most important components in the car-bon(c)cycle in terrestrial ecosystems.to investigate the contribution of each component of c cycle to the total soil c efflux,we quantified the ...Aims Soil respiration is one of the most important components in the car-bon(c)cycle in terrestrial ecosystems.to investigate the contribution of each component of c cycle to the total soil c efflux,we quantified the rates of litter,root,and other mineral soil respiration from 2012 to 2014 in the primary and secondary tropical mountain rain forests in Hainan Island,china.Methods the seasonal dynamics of soil(Rs),non-litter(RNL)and non-root(RNR)respiration rates were measured using an automatic chamber system(Li-8100).Litter removal and root removal treatments were used to assess the contribution of litter and roots to belowground c production.We estimated the annual c efflux of each compo-nent of soil respiration in primary and secondary forests using a temperature-based exponential model and analyzed the impact of each component in each forest type.Important Findingsthe annual total soil c efflux was significantly higher in the primary rain forest(1567±205 g c m^(−2)yr^(−1))than that in the secondary forest(1300±70 g c m^(−2)yr^(−1),P<0.05).the litter,root,and mineral soils contributed 22%(349±185 g c m^(−2)yr^(−1)),38%(589±100 g c m^(−2)yr^(−1)),and 40%(628±128 g c m^(−2)yr^(−1))to the total soil c efflux in primary rain forest,respectively.In secondary forest,these three components contributed 11%(148±35 g c m^(−2)yr^(−1)),45%(572±259 g c m^(−2)yr^(−1)),and 44%(580±226 g c m^(−2)yr^(−1)),respectively.the temperature sensitivity(Q10)of Rs(2.70±0.14)in the primary forest was significantly higher than that in the secondary forest(2.34±0.12),with the Q10 values for respiration decreasing in the order of RNR>Rs>RNL.these results show that the difference in litter respiration between primary and secondary forest caused the major difference in annual soil respiration efflux between these two forest types.In addition,the litter respiration is more sensitive to the soil temperature than the other soil respiration components.展开更多
Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynami...Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynamics. This might also hold for the mixed evergreen broadleaved and deciduous forests in the mountains of subtropical China, but until now little existing knowledge is available for this question. In 2001, we chose to monitor the seed rain process of our mixed evergreen broad-leaved and deciduous forest communities in Mount Dalaoling National Forest Park, Yichang, Hubei Province, China. The preliminary analyses show obvious variations in seed rain density, species compositions and timing of seed rain among four communities. The average seed rain densities of the four communities are 2.43 ± 5.15, 54.13 ±182.75, 10.05 ±19.30 and 24.91 ± 58.86 inds/m^2, respectively; about one tenth the values in other studies in subtropical forests of China. in each community, the seed production is dominated by a limited number of species, and the contributions from the others are generally minor. Fecundity of evergreen broadleaved tree species is weaker than deciduous species. The seed rain of four communities begins earlier than September, and stops before December, peaking from early September to late October. The beginning date, ending date and peak times of seed rain are extensively varied among the species, indicating different types of dispersal strategies. According to the existing data, the timing of seed rain is not determined by the climate conditions in the same period, while the density of seed rain may be affected by the disturbances of weather variations at a finer temporal resolution.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 40601009),the A3 Foresight Programthe Special Research Program of Research Institute for Tropical Forestry,Chinese Academy of Forestry (Grant No. 2007-1, RITFYWZX200902)+2 种基金 the Special Research Program for Public-welfare Forestry (Grant No. 200804001) the Eleventh-Five-Year Scientific Support Program of the State Forestry Administration of China (Grant Nos. 2006BAD03A07 and 2006BAD03A04)the "948" Program of State Forestry Administration of China (Grant No. 2007-4-18)
文摘Biometric inventories for 25 years,from 1983 to 2005,indicated that the Jianfengling tropical mountain rain forest in Hainan,China,was either a source or a modest sink of carbon.Overall,this forest was a small carbon sink with an accumulation rate of(0.56±0.22) Mg C ha-1yr-1,integrated from the long-term measurement data of two plots(P9201 and P8302).These findings were similar to those for African and American rain forests((0.62±0.23) Mg C ha-1yr-1).The carbon density varied between(201.43±29.38) Mg C ha-1 and(229.16±39.2) Mg C ha-1,and averaged(214.17±32.42) Mg C ha-1 for plot P9201.Plot P8302,however,varied between(223.95±45.92) Mg C ha-1 and(254.85±48.86) Mg C ha-1,and averaged(243.35±47.64) Mg C ha-1.Quadratic relationships were found between the strength of carbon sequestration and heavy rainstorms and dry months.Precipitation and evapotranspiration are two major factors controlling carbon sequestration in the tropical mountain rain forest.
基金National Natural Science Foundation of China(31321061,31330012)National Basic Research Program of China on Global Change(2014CB954001).
文摘Aims Soil respiration is one of the most important components in the car-bon(c)cycle in terrestrial ecosystems.to investigate the contribution of each component of c cycle to the total soil c efflux,we quantified the rates of litter,root,and other mineral soil respiration from 2012 to 2014 in the primary and secondary tropical mountain rain forests in Hainan Island,china.Methods the seasonal dynamics of soil(Rs),non-litter(RNL)and non-root(RNR)respiration rates were measured using an automatic chamber system(Li-8100).Litter removal and root removal treatments were used to assess the contribution of litter and roots to belowground c production.We estimated the annual c efflux of each compo-nent of soil respiration in primary and secondary forests using a temperature-based exponential model and analyzed the impact of each component in each forest type.Important Findingsthe annual total soil c efflux was significantly higher in the primary rain forest(1567±205 g c m^(−2)yr^(−1))than that in the secondary forest(1300±70 g c m^(−2)yr^(−1),P<0.05).the litter,root,and mineral soils contributed 22%(349±185 g c m^(−2)yr^(−1)),38%(589±100 g c m^(−2)yr^(−1)),and 40%(628±128 g c m^(−2)yr^(−1))to the total soil c efflux in primary rain forest,respectively.In secondary forest,these three components contributed 11%(148±35 g c m^(−2)yr^(−1)),45%(572±259 g c m^(−2)yr^(−1)),and 44%(580±226 g c m^(−2)yr^(−1)),respectively.the temperature sensitivity(Q10)of Rs(2.70±0.14)in the primary forest was significantly higher than that in the secondary forest(2.34±0.12),with the Q10 values for respiration decreasing in the order of RNR>Rs>RNL.these results show that the difference in litter respiration between primary and secondary forest caused the major difference in annual soil respiration efflux between these two forest types.In addition,the litter respiration is more sensitive to the soil temperature than the other soil respiration components.
基金the National Natural Science Foundation of China(30000024,30470313).
文摘Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynamics. This might also hold for the mixed evergreen broadleaved and deciduous forests in the mountains of subtropical China, but until now little existing knowledge is available for this question. In 2001, we chose to monitor the seed rain process of our mixed evergreen broad-leaved and deciduous forest communities in Mount Dalaoling National Forest Park, Yichang, Hubei Province, China. The preliminary analyses show obvious variations in seed rain density, species compositions and timing of seed rain among four communities. The average seed rain densities of the four communities are 2.43 ± 5.15, 54.13 ±182.75, 10.05 ±19.30 and 24.91 ± 58.86 inds/m^2, respectively; about one tenth the values in other studies in subtropical forests of China. in each community, the seed production is dominated by a limited number of species, and the contributions from the others are generally minor. Fecundity of evergreen broadleaved tree species is weaker than deciduous species. The seed rain of four communities begins earlier than September, and stops before December, peaking from early September to late October. The beginning date, ending date and peak times of seed rain are extensively varied among the species, indicating different types of dispersal strategies. According to the existing data, the timing of seed rain is not determined by the climate conditions in the same period, while the density of seed rain may be affected by the disturbances of weather variations at a finer temporal resolution.
