Climate change has posed a great risk and treats to global environment.To address the problem,international community resorts to carbon emission reduction,and many countries have implemented afforestation and reforest...Climate change has posed a great risk and treats to global environment.To address the problem,international community resorts to carbon emission reduction,and many countries have implemented afforestation and reforestation project under Clean Development Mechanism.China started the research and has done a great load of works on forest carbon trade as early as the year of 2002 to contribute to the carbon emission reduction.This paper introduces the implementation of forest carbon trade in Heyuan City,Guan...展开更多
Health condition and replacement time of terminal bud were selected as quality indexes of regenerated seedlings in 3 different growth forms to analyze their impact on seedling height and ground diameter. The results s...Health condition and replacement time of terminal bud were selected as quality indexes of regenerated seedlings in 3 different growth forms to analyze their impact on seedling height and ground diameter. The results showed that quality of terminal bud was related to the seedling growth, the regenerated seedlings with healthy terminal buds but no replacement experienced the largest growth amount and slight damage of terminal bud or one replacement stimulated growth of ground diameter. Multiple replacements of terminal bud would reduce seedling quality and influence its growth. Exploration of the quality characters of seedlings helped to know the dynamic features of early seedling growth, and provided theoretical support for the tending operation to improve quality of natural tropical forest.展开更多
Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importanc...Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.展开更多
Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availab...Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availability after a certain number of years following conversion.Nutrient resorption prior to leaf senescence was related to soil fertility,an important nutrient conservation strategy for plants,being especially significant in nutrient-poor habitats.However,the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations(Larix spp.)and adjacent secondary forests(dominant tree species including Quercus mongolica,Acer mono,Juglans mandshurica and Fraxinus rhynchophylla)was conducted.We examined the variations in leaf nutrient(macronutrients:N,P,K,Ca and Mg;micronutrients:Cu and Zn)concentrations of these tree species during the growing season from May to October in 2013.Nutrient resorption efficiency and proficiency were compared between Larix spp.and the broadleaved species in the secondary forests.Important Findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends,one was a downward trend for N,P,K,Cu and Zn,and another was an upward trend for Ca and Mg.The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species.Resorption of the observed seven elements varied among the five tree species during leaf senescence.Nutrient resorption efficiency varied 6–75%of N,P,K,Mg,Cu and Zn,while Ca was not retranslocated in the senescing leaves of all species,and Mg was not retranslocated in Larix spp.Generally,Larix spp.tended to be more efficient and proficient(higher than 6–30%and 2–271%of nutrient resorption efficiency and resorption proficiency,respectively)in resorbing nutrients than the broadleaved species in the secondary forests,indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency.Compared with Larix spp.,more nutrients would remain in the leaf litter of the secondary forests,indicating an advantage of secondary forests in sustaining soil fertility.In contrast,the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability.In summary,our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plantmediated pathway.展开更多
基金Supported by ITTO Project"Creating and Sustaining a Market for Environmental Services from China's Tropical Forest"[PD 295/04 Rev.2(M)]
文摘Climate change has posed a great risk and treats to global environment.To address the problem,international community resorts to carbon emission reduction,and many countries have implemented afforestation and reforestation project under Clean Development Mechanism.China started the research and has done a great load of works on forest carbon trade as early as the year of 2002 to contribute to the carbon emission reduction.This paper introduces the implementation of forest carbon trade in Heyuan City,Guan...
基金Operation Subsidy for Hainan Wenchang Forest Ecosystem National Positioning Observation and Research Station(2015-LYPT-DW-095)
文摘Health condition and replacement time of terminal bud were selected as quality indexes of regenerated seedlings in 3 different growth forms to analyze their impact on seedling height and ground diameter. The results showed that quality of terminal bud was related to the seedling growth, the regenerated seedlings with healthy terminal buds but no replacement experienced the largest growth amount and slight damage of terminal bud or one replacement stimulated growth of ground diameter. Multiple replacements of terminal bud would reduce seedling quality and influence its growth. Exploration of the quality characters of seedlings helped to know the dynamic features of early seedling growth, and provided theoretical support for the tending operation to improve quality of natural tropical forest.
基金financially supported by the Innovation Foundation for Doctoral Program of Forestry Engineering of Northeast Forestry University,grant number:LYGC202117the China Scholarship Council(CSC),grant number:202306600046+1 种基金the Research and Development Plan of Applied Technology in Heilongjiang Province of China,grant number:GA19C006Research and Demonstration on Functional Improvement Technology of Forest Ecological Security Barrier in Heilongjiang Province,grant number:GA21C030。
文摘Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.
基金National Basic Research Program of China(973 Program)(2012CB416906)State Key Laboratory of Forest and Soil Ecology(LFSE2013-11).
文摘Aims Conversion of secondary forests to pure larch plantations is a common management practice driven by the increasing demand for timber production in Northeast China,resulting in a reduction in soil nutrient availability after a certain number of years following conversion.Nutrient resorption prior to leaf senescence was related to soil fertility,an important nutrient conservation strategy for plants,being especially significant in nutrient-poor habitats.However,the seasonal dynamics of leaf nutrients and nutrient resorption in response to secondary forest conversion to larch plantations is not well understood.Methods A comparative experiment between larch plantations(Larix spp.)and adjacent secondary forests(dominant tree species including Quercus mongolica,Acer mono,Juglans mandshurica and Fraxinus rhynchophylla)was conducted.We examined the variations in leaf nutrient(macronutrients:N,P,K,Ca and Mg;micronutrients:Cu and Zn)concentrations of these tree species during the growing season from May to October in 2013.Nutrient resorption efficiency and proficiency were compared between Larix spp.and the broadleaved species in the secondary forests.Important Findings Results show that the seasonal variation of nutrient concentrations in leaves generally exhibited two trends,one was a downward trend for N,P,K,Cu and Zn,and another was an upward trend for Ca and Mg.The variations in foliar nutrient concentrations were mainly controlled by the developmental stage of leaves rather than by tree species.Resorption of the observed seven elements varied among the five tree species during leaf senescence.Nutrient resorption efficiency varied 6–75%of N,P,K,Mg,Cu and Zn,while Ca was not retranslocated in the senescing leaves of all species,and Mg was not retranslocated in Larix spp.Generally,Larix spp.tended to be more efficient and proficient(higher than 6–30%and 2–271%of nutrient resorption efficiency and resorption proficiency,respectively)in resorbing nutrients than the broadleaved species in the secondary forests,indicating that larch plantations had higher leaf nutrient resorption and thus nutrient use efficiency.Compared with Larix spp.,more nutrients would remain in the leaf litter of the secondary forests,indicating an advantage of secondary forests in sustaining soil fertility.In contrast,the larch plantation would reuse internal nutrients rather than lose nutrients with litter fall and thus produce a positive feedback to soil nutrient availability.In summary,our results suggest that conversion from secondary forests to pure larch plantations would alter nutrient cycling through a plantmediated pathway.
