AS a foreigner anywhere, it is important to make an effort to experience the cultural heritage of the city you are in. In Paris you should visit Montmartre, in London you can＇t miss Buckingham Palace, and before you ...AS a foreigner anywhere, it is important to make an effort to experience the cultural heritage of the city you are in. In Paris you should visit Montmartre, in London you can＇t miss Buckingham Palace, and before you leave Sydney, a trip to the Blue Mountains is essential, For Beiiing, the unquestionable birthplace of Chinese culture is buried deep within the city＇s ancient hutongs.展开更多
Background:The heartwood(HW)proportion in the trunk of mature trees is an important characteristic not only for wood quality but also for assessing the role of forests in carbon sequestration.We have for the first tim...Background:The heartwood(HW)proportion in the trunk of mature trees is an important characteristic not only for wood quality but also for assessing the role of forests in carbon sequestration.We have for the first time studied the proportion of HW in the trunk and the distribution of carbon and extractives in sapwood(SW)and HW of 70–80 year old Pinus sylvestris L.trees under different growing conditions in the pine forests of North-West Russia.Method:We have examined the influence of conditions and tree position in stand(dominant,intermediate and suppressed trees)in the ecological series:blueberry pine forest(Blu)–lingonberry pine forest(Lin)–lichen pine forest(Lic).We have analyzed the influence of climate conditions in the biogeographical series of Lin:the middle taiga subzone–the northern taiga subzone–the transition area of the northern taiga subzone and tundra.Results:We found that the carbon concentration in HW was 1.6%–3.4%higher than in SW,and the difference depended on growing conditions.Carbon concentration in HW increased with a decrease in stand productivity(Blu-Lin-Lic).In medium-productive stands,the carbon concentration in SW was higher in intermediate and supressed trees compared to dominant trees.In the series from south to north,carbon concentration in HW increased by up to 2%,while in SW,it rose by 2.7%–3.8%.Conclusions:Our results once again emphasized the need for an empirical assessment of the accurate carbon content in aboveground wood biomass,including various forest growing conditions,to better understand the role of boreal forests in carbon storage.展开更多
Afforestation on formerly cultivated or aban-doned agricultural land is a common strategy to increase forest areas and enhance carbon sequestration.Deep soil ploughing before afforestation improves soil conditions,fac...Afforestation on formerly cultivated or aban-doned agricultural land is a common strategy to increase forest areas and enhance carbon sequestration.Deep soil ploughing before afforestation improves soil conditions,facilitating tree growth and carbon storage.This study assessed the growth and biomass parameters of Pinus sylves-tris in 10-and 20 years old plantations established on deeply ploughed and non-ploughed soils in Lithuania.Biomass allocation and carbon and nutrient concentrations including N,P,K,Ca and Mg were analysed in aboveground biomass components.Deep ploughing in the 10 years old stands negatively impacted vertical growth and stem development but did not significantly affect overall biomass accumula-tion.In contrast,in the 20 years old stands,deep plough-ing resulted in taller trees with larger diameters and higher biomass accumulation compared to non-ploughed sites.Biomass distribution within tree canopies varied between ploughed and non-ploughed sites,indicating diverse effects of deep ploughing.Carbon and nutrient concentrations in biomass components showed site-specific variations,with deep ploughing influencing carbon concentrations in needles and stem bark.Overall,deep ploughing showed potential for enhancing tree growth and biomass accumulation,with implications for carbon sequestration in forest ecosystems.These findings help us understand the impact of an alternative soil management practice,deep ploughing,on forest development and carbon dynamics.展开更多
Understanding why elements are distributed in tree xylem in a particular way is a significant challenge in dendrochemistry.This study explored a hypothesis that metal elements in the xylem interact due to differences ...Understanding why elements are distributed in tree xylem in a particular way is a significant challenge in dendrochemistry.This study explored a hypothesis that metal elements in the xylem interact due to differences in physical properties such as ionic radius and ionization potential.Scots pine in an even-aged stand established during the early 1970s in eastern Siberia was the study species.Increment cores were taken from the north and south sides of trees and scanned with an X-ray fluorescent multi scanner.With the help of X-ray scanning,the following elements were analyzed:aluminum(Al),potassium(K),calcium(Ca),titanium(Ti),manganese(Mn),iron(Fe),copper(Cu),strontium(Sr)and zinc(Zn).Scanning data on the elements were split into early-wood and late-wood data for each year of growth.The following ratios were analyzed:Ca/Sr,Fe/Ca,Fe/Sr,Al/Cu,Al/Zn,Ti/Mn,and Mn/K.Among these,ones having a consistent pattern across tree rings,the ratios show a more or less dependable relationship:that an element shows a larger decrease(relative another element)that has a larger ionic radius and lower ionization potential.Hypothetically,this may be due to the advantage of an ion with smaller ionic radius and higher ionization potential under a deficit of accommodation centers in organic molecules.An experiment approach should be applied to clarify the relationships.展开更多
The effectiveness of fluopyram suspension concentrate against pine wilt disease(PWD)is limited by spraying efficiency and water dependence.A traditional dust formulation with strong dispersibility can overcome these s...The effectiveness of fluopyram suspension concentrate against pine wilt disease(PWD)is limited by spraying efficiency and water dependence.A traditional dust formulation with strong dispersibility can overcome these shortcomings.However,its efficacy against PWD remains uncertain.This study evaluated the translocation of fluopyram dust within tree tissues,soil and water degradation,and its effective control against PWD.Nursery tests showed effective prevention;field tests showed dust absorption and translocation into pine tissues.Thirty days following application,residual concentrations in soil were low at 0.09 mg kg^(−1);no detectable residues were found in water samples.Three years after applying fluopyram,its effectiveness increased to approximately 87%.Based on this study,fluopyram had a half-life of 346 d with persistence lasting up to three years.This provides valuable insight for managing PWD through dust applications.展开更多
A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into m...A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into multi-aged stands.For shade-intolerant pines of the southern United States,however,few studies have examined residual tree growth following silvicultural treatments that convert even-aged stands to multi-aged stands.Understanding the growth response of residual trees to different kinds of stand conversion treatments is critical to stand development and sustainability,as trees must be recruited into larger size classes during the conversion process to develop the desired stand structure and maintain productivity.In this study,we utilized a replicated,long-term silvicultural experimental trial in the southeastern United States to assess the effects of two cutting treatments(dispersed"single tree cutting"that created small canopy gaps and the"patch cutting"that created 0.1-0.8ha patch openings)and an uncut control on the 14-year growth(~cutting cycle length)of residual longleaf pine(Pinus palustris Mill.)trees.We found that tree growth,measured as mean basal area increment(BAI),was significantly higher following patch cutting(mean BAI of 16.97cm^(2))compared to both the single tree cutting(13.33cm^(2))and the uncut control(12.68cm^(2))(p<0.001).In patch cutting,the size of the patch opening,the location of trees surrounding the patch opening,and the position of the tree canopy all had a significant effect on BAI.Trees surrounding patch openings of 0.4ha exhibited greater growth,with a mean BAI of 19.24cm^(2),compared to those surrounding 0.1 and 0.8ha patch openings,which had mean BAI values of 15.89 and 15.71cm^(2),respectively(p<0.001).The position of a tree around the patch opening also influenced tree growth,as residual trees more to the North,South,and East sides exhibited significantly higher mean BAI than trees on the West side of the patch openings(p<0.001).However,distance from the patch opening border did not significantly affect the mean BAI(p=0.522).In all treatments,dominant and co-dominant trees exhibited higher BAI than intermediate and overtopped trees,indicating that tree canopy position significantly influenced tree growth(p<0.001).Understanding how residual trees grow after these silvicultural treatments is crucial for thoroughly assessing their efficacy with longleaf pine.This study's findings will enhance our understanding of stand dynamics during stand conversion and help land managers anticipate the growth of longleaf pine into larger size categories after single tree and patch cuttings.展开更多
Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. ...Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.展开更多
We tested the effectiveness of the gradual removal of Scots pine(Pinus sylvestris L.)in former plantations of this species in Roztocze National Park(SE Poland)to support the restoration of natural herbaceous flora and...We tested the effectiveness of the gradual removal of Scots pine(Pinus sylvestris L.)in former plantations of this species in Roztocze National Park(SE Poland)to support the restoration of natural herbaceous flora and forest structure.We compared 0.5-ha study plots subjected to selective removal of pine trees with control plots excluded from any kind of human intervention for half a century.The observed changes in forest floor vegetation in the converted plots showed naturalization towards habitat-specific species.However,differences in the spatial distribution of trees between the treatment and control plots showed no universal pattern and revealed subtle but positive shifts from regular to random or clustered patterns.The mean tree diameters were higher in plots subjected to Scots pine removal,which resulted from the vigorous growth of tree species,consistent with habitat types.We conclude that forest restoration through the removal of planted trees can support the naturalization of former Scots pine plantations in protected areas.However,the selection of an appropriate method and its intensity are of vital importance.Methods that resemble typical management practices,such as selection thinning,are not always the best approach,as they may preserve or even increase the regular distribution of trees.Therefore,for restoration purposes,we recommend testing other methods that increase spatial heterogeneity,including systematic cutting or emulating natural disturbances.In addition,low-intensity thinning may not be sufficient to support the restoration of natural forest floor vegetation and the variability in forest stand structure.展开更多
Forest management planning faces uncertainties regarding future timber prices,tree growth,and survival.Future seed production is an additional source of uncertainty in Korean pine stands managed for the joint producti...Forest management planning faces uncertainties regarding future timber prices,tree growth,and survival.Future seed production is an additional source of uncertainty in Korean pine stands managed for the joint production of timber and edible seeds.Modern forest planning uses optimisation to determine the best possible cutting schedule.Optimisation can accommodate uncertainty by using decision rules for adaptive forest management instead of optimising cutting years and intensities.In this study,we optimised two adaptive decision rules for managing Korean pine plantations for the joint production of timber and pinecones when timber prices,tree growth,and seed production are stochastic.The first rule indicated the minimum price to sell timber,i.e.,the reservation price,as a function of the mean tree diameter and stand basal area.The second adaptive rule expressed the mean tree diameter at which cutting is optimal as a function of timber price and stand basal area.Both decision rules resulted in nearly the same mean net present value when the optimised rule was applied to 100 stochastic scenarios for future timber prices,tree growth,and seed production.The net present values were over 20% higher than those for the deterministically optimised cutting schedules under the same scenarios.Therefore,the expected economic gain from switching from deterministic to adaptive stochastic optimisation was at least 20%.The cutting years of the adaptive optima were frequently later than those indicated by the deterministic optima,and optimal adaptive harvesting often involved waiting for high timber prices.The minimum price or minimum mean diameter to sell timber was higher when the income from seeds was considered in the optimisation.The cuttings were later,and the rotations were longer in the joint production of timber and pinecones than in timber production alone.展开更多
This study evaluated the long-term growth responses of pine plantations in the Lower Coastal Plain of Florida to different site preparation(SP)treatments,including variations in bedding timing(early or late),frequency...This study evaluated the long-term growth responses of pine plantations in the Lower Coastal Plain of Florida to different site preparation(SP)treatments,including variations in bedding timing(early or late),frequency(single or double),and herbicide use(banded or broadcast pre-plant application),with or without first-year post-plant herbaceous weed control(HWC).The results showed that growth responses varied by location,primarily influenced by the effectiveness of vegetation control,especially in suppressing woody shrubs.Pre-plant herbicide treatments consistently improved growth,with broadcast applications often performing as well or better than the banded treatments.Although bedding timing and frequency influenced growth at some sites,their effects were inconsistent.Superior growth was observed in treatments combining early bedding with pre-plant herbicide,even without HWC,highlighting the critical role of effective vegetation management in enhancing the productivity of pine plantations.展开更多
Based on the survey data of nine primitive broad-leaved Korean pine forest plots ranging from 1 to 10.4 ha in Heilongjiang Province,this study used the moving window method and GIS technology to analyze the variation ...Based on the survey data of nine primitive broad-leaved Korean pine forest plots ranging from 1 to 10.4 ha in Heilongjiang Province,this study used the moving window method and GIS technology to analyze the variation characteristics of the spatial distribution pattern of forest biomass in each plot.We explored the minimum area that can reflect the structural and functional characteristics of the primitive broad-leaved Korean pine forest,and used computer simulation random sampling method to verify the accuracy of the minimum area.The results showed that:(1)Through the analysis of the spatial distribution raster map of biomass deviation in the plots at various scales of 10−100 m,there is a minimum area(0.64 ha)for the critical range of biomass density variation in the primitive broad-leaved Korean pine forest.This minimum area based on biomass density can indirectly reflect the comprehensive characteristics of productivity level per unit area,structure,function,and environmental quality of the primitive broad-leaved Korean pine forest community.(2)Using computer simulation random sampling,it was found that only by sampling in a specific plot larger than or equal to the minimum area can equivalent or similar results be achieved as random sampling within the plot,indicating that the minimum area determined by the moving window method is accurate.(3)The minimum area determined in this paper is an excellent indicator reflecting the complexity of community structure,which can be used for comparing changes in community structure and function before and after external disturbances,and has a good evaluation effect.This minimum area can also be used as a basis for scientific and reasonable setting of plot size in the investigation and monitoring work of broad-leaved Korean pine forests in this region,thereby achieving the goals of improving work efficiency and saving work costs.展开更多
We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speed...We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speeds from 9 to 32 m s^(-1),jet core heights from 80 to 800 m,and were associated with strong,low-level temperature inversions.Seven of the observed offshore LLJs were reasonably simulated by the polar-optimized Weather Research and Forecasting(Polar WRF)model,with output from the model subsequently used to elucidate their generation mechanisms.This study shows that one of the offshore LLJs simulated by the Polar WRF was caused by katabatic winds,while the remaining six were caused by the enhancement of katabatic winds by synoptic forcing in response to a low-pressure system over the Bellingshausen Sea,i.e.,the offshore wind component associated with this system plays a crucial role in the enhancement of the katabatic LLJ.Examination of the Polar WRF output further shows that the LLJs extended over large areas of the Amundsen Sea Embayment,resulting in substantially enhanced near-surface wind speeds over both the Thwaites and Pine Island ice shelves,as well as the open ocean over the continental shelf.The wind-driven forcing associated with the LLJs could perhaps have important impacts on the redistribution of snow over the ice shelves significantly,as well as to affecting sea-ice and ocean circulation variability,including the transport of relatively warm water over the continental shelf to the ice shelf cavities and extension basal melting.展开更多
Human activities contribute to elevated nitrogen input in terrestrial ecosystems,influencing the composition of soil nutrients and microbial diversity in forest ecosystems.In this study,we built four addition treatmen...Human activities contribute to elevated nitrogen input in terrestrial ecosystems,influencing the composition of soil nutrients and microbial diversity in forest ecosystems.In this study,we built four addition treatments(0,20,40,and 80 kg ha^(−1)a^(−1)N for 6 a)at a Korean pine plantation of different soil horizons(organic(O)horizon,ranging from 0 to 10 cm,and organomineral(A)horizon,extending from 10 to 20 cm)to evaluate responses of the structure of saprophytic fungal communities.Here,80 kg ha^(−1)a^(−1)N treatment significantly decreased the community richness in soil A horizon with the Chao1 index decreasing by 12.68%.Nitrogen addition induced changes in the composition of saprophytic fungi community between the different soil horizons.The co-occurrence network and its associated topological structure were utilized to identify mycoindicators for specific fungi to both soil horizons and nitrogen addition levels.In soil O horizon,the mycoindicators included Penicillium,Trichoderma,Aspergillus,and Pseudeurotium across control,low,medium,and high nitrogen treatments.In soil A horizon,Geomyces,Cladophialophora,Penicillium,and Pseudeurotium were identified as mycoindicators.Structural equation modeling determined NH_(4)^(+)-N as the key factor driving changes in saprotrophic fungal communities.Our study aimed to screen mycoindicators that can respond to the increasing global nitrogen deposition and to assess the roles of these mycoindicators in the saprophytic fun-gal community structure within Korean pine plantations in northeast China.展开更多
The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will ...The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will occur mainly at the edges of the species ranges.We focused on the responses to climate change of the drought-resistant larch(Larix sibirica)and the moisture-sensitive Siberian pine(Pinus sibirica)along the elevation gradient in the Tannu-Ola Ridge,the southern margin where those two species coexist in Siberia by using satellite data(MODIS,Landsat,and microwave),the indexes of gross(GPP)and net(NPP)primary productivity,and tree radial growth index(GI).We found that since the warming restart in the 2000s,the area of larch-dominated forests increased by~150%while the area of pine-dominated forests decreased by~10%.The Siberian pine has retreated at low elevations(<1800 m)and increased its area at higher ones.In contrast,the area of larch stands increased in both the uphill and downhill directions.Birch(Betula spp.)also increased its area at low elevations(about+120%).Since 2001,the forested area increased by~5%.A shrubification,i.e.,an increase in the area of shrubs,was observed at high elevations.The uphill rate of timberline and shrubline migration was about 0.3 m/a.Since the 2000s,vegetation NPP has increased by 13%.A notable correlation between NPP and the GI of larch and pine was found(r=0.5-0.7).At lower elevations,NPP positively correlated with precipitation and soil moisture,while air temperature and VPD(vapor pressure deficit)increase inhibited productivity.At high elevations,the effects of these variables on productivity reversed.The continuous decline of the Siberian pine forest indicates an inevitable retreat of this species at low elevations and its replacement by larch and birch.展开更多
Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of Chi...Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of China), but many problems occurred in the earliest Mongolian pine plantations in Zhanggutai, Zhangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively. Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11, 22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings' disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.展开更多
文摘AS a foreigner anywhere, it is important to make an effort to experience the cultural heritage of the city you are in. In Paris you should visit Montmartre, in London you can＇t miss Buckingham Palace, and before you leave Sydney, a trip to the Blue Mountains is essential, For Beiiing, the unquestionable birthplace of Chinese culture is buried deep within the city＇s ancient hutongs.
基金carried out within the framework of the most important innovative project of state importance“Development of a system of ground-based and remote monitoring of carbon pools and greenhouse gas fluxes on the territory of the Russian Federation,…”(No.123030300031-6)in the northern taiga subzone and on the border of tundra and taiga under the state assignment of the Forest Institute of the Karelian Research Center of the Russian Academy of Sciences(FMEN-2021-0018)with the partial financial support from RSF(grant no.21-14-00204)。
文摘Background:The heartwood(HW)proportion in the trunk of mature trees is an important characteristic not only for wood quality but also for assessing the role of forests in carbon sequestration.We have for the first time studied the proportion of HW in the trunk and the distribution of carbon and extractives in sapwood(SW)and HW of 70–80 year old Pinus sylvestris L.trees under different growing conditions in the pine forests of North-West Russia.Method:We have examined the influence of conditions and tree position in stand(dominant,intermediate and suppressed trees)in the ecological series:blueberry pine forest(Blu)–lingonberry pine forest(Lin)–lichen pine forest(Lic).We have analyzed the influence of climate conditions in the biogeographical series of Lin:the middle taiga subzone–the northern taiga subzone–the transition area of the northern taiga subzone and tundra.Results:We found that the carbon concentration in HW was 1.6%–3.4%higher than in SW,and the difference depended on growing conditions.Carbon concentration in HW increased with a decrease in stand productivity(Blu-Lin-Lic).In medium-productive stands,the carbon concentration in SW was higher in intermediate and supressed trees compared to dominant trees.In the series from south to north,carbon concentration in HW increased by up to 2%,while in SW,it rose by 2.7%–3.8%.Conclusions:Our results once again emphasized the need for an empirical assessment of the accurate carbon content in aboveground wood biomass,including various forest growing conditions,to better understand the role of boreal forests in carbon storage.
基金supported by the Long-term Research Programme“Sustainable Forestry and Global Changes”,conducted by the Lithuanian Research Centre for Agriculture and Forestry(LAMMC).
文摘Afforestation on formerly cultivated or aban-doned agricultural land is a common strategy to increase forest areas and enhance carbon sequestration.Deep soil ploughing before afforestation improves soil conditions,facilitating tree growth and carbon storage.This study assessed the growth and biomass parameters of Pinus sylves-tris in 10-and 20 years old plantations established on deeply ploughed and non-ploughed soils in Lithuania.Biomass allocation and carbon and nutrient concentrations including N,P,K,Ca and Mg were analysed in aboveground biomass components.Deep ploughing in the 10 years old stands negatively impacted vertical growth and stem development but did not significantly affect overall biomass accumula-tion.In contrast,in the 20 years old stands,deep plough-ing resulted in taller trees with larger diameters and higher biomass accumulation compared to non-ploughed sites.Biomass distribution within tree canopies varied between ploughed and non-ploughed sites,indicating diverse effects of deep ploughing.Carbon and nutrient concentrations in biomass components showed site-specific variations,with deep ploughing influencing carbon concentrations in needles and stem bark.Overall,deep ploughing showed potential for enhancing tree growth and biomass accumulation,with implications for carbon sequestration in forest ecosystems.These findings help us understand the impact of an alternative soil management practice,deep ploughing,on forest development and carbon dynamics.
基金supported by the Russian Science Foundation(grant No.:23-44-00067).
文摘Understanding why elements are distributed in tree xylem in a particular way is a significant challenge in dendrochemistry.This study explored a hypothesis that metal elements in the xylem interact due to differences in physical properties such as ionic radius and ionization potential.Scots pine in an even-aged stand established during the early 1970s in eastern Siberia was the study species.Increment cores were taken from the north and south sides of trees and scanned with an X-ray fluorescent multi scanner.With the help of X-ray scanning,the following elements were analyzed:aluminum(Al),potassium(K),calcium(Ca),titanium(Ti),manganese(Mn),iron(Fe),copper(Cu),strontium(Sr)and zinc(Zn).Scanning data on the elements were split into early-wood and late-wood data for each year of growth.The following ratios were analyzed:Ca/Sr,Fe/Ca,Fe/Sr,Al/Cu,Al/Zn,Ti/Mn,and Mn/K.Among these,ones having a consistent pattern across tree rings,the ratios show a more or less dependable relationship:that an element shows a larger decrease(relative another element)that has a larger ionic radius and lower ionization potential.Hypothetically,this may be due to the advantage of an ion with smaller ionic radius and higher ionization potential under a deficit of accommodation centers in organic molecules.An experiment approach should be applied to clarify the relationships.
基金supported by grants from the National Key R&D Program of China(grant number 2021YFD1400900)the National Natural Science Foundation of China(grant numbers U1905201,32171805)+6 种基金the Forestry Key Program of Science and Technology in Fujian Province(grant number 2021FKJ03)the Natural Science Foundation of Fujian Province,China(grant number 2021J01056)the Forestry Programs of Science and Technology in Fujian Province[grant number Mincaizhi(2020)601]the Science and Technology Program of Fujian Province(grant number 2018N5002)the Forestry Science Research Project of Fujian Forestry Department[grant number Minlinke(2017)03]the National Major Emergency Science and Technology Program of China(grant number ZD202001)the Forestry Peak Discipline Construction Project of Fujian Agriculture and Forestry University(grant numbers 72202200205,71201800720).
文摘The effectiveness of fluopyram suspension concentrate against pine wilt disease(PWD)is limited by spraying efficiency and water dependence.A traditional dust formulation with strong dispersibility can overcome these shortcomings.However,its efficacy against PWD remains uncertain.This study evaluated the translocation of fluopyram dust within tree tissues,soil and water degradation,and its effective control against PWD.Nursery tests showed effective prevention;field tests showed dust absorption and translocation into pine tissues.Thirty days following application,residual concentrations in soil were low at 0.09 mg kg^(−1);no detectable residues were found in water samples.Three years after applying fluopyram,its effectiveness increased to approximately 87%.Based on this study,fluopyram had a half-life of 346 d with persistence lasting up to three years.This provides valuable insight for managing PWD through dust applications.
基金The USDA NIFA McIntire Stennis project#1014653 and the University of Florida Institute of Food and Agricultural Sciences funded the research presented in this publication.
文摘A growing recognition that uneven-aged silviculture can offer multiple benefits to forested ecosystems has encouraged some landowners in the southern region of the United States to convert even-aged pine stands into multi-aged stands.For shade-intolerant pines of the southern United States,however,few studies have examined residual tree growth following silvicultural treatments that convert even-aged stands to multi-aged stands.Understanding the growth response of residual trees to different kinds of stand conversion treatments is critical to stand development and sustainability,as trees must be recruited into larger size classes during the conversion process to develop the desired stand structure and maintain productivity.In this study,we utilized a replicated,long-term silvicultural experimental trial in the southeastern United States to assess the effects of two cutting treatments(dispersed"single tree cutting"that created small canopy gaps and the"patch cutting"that created 0.1-0.8ha patch openings)and an uncut control on the 14-year growth(~cutting cycle length)of residual longleaf pine(Pinus palustris Mill.)trees.We found that tree growth,measured as mean basal area increment(BAI),was significantly higher following patch cutting(mean BAI of 16.97cm^(2))compared to both the single tree cutting(13.33cm^(2))and the uncut control(12.68cm^(2))(p<0.001).In patch cutting,the size of the patch opening,the location of trees surrounding the patch opening,and the position of the tree canopy all had a significant effect on BAI.Trees surrounding patch openings of 0.4ha exhibited greater growth,with a mean BAI of 19.24cm^(2),compared to those surrounding 0.1 and 0.8ha patch openings,which had mean BAI values of 15.89 and 15.71cm^(2),respectively(p<0.001).The position of a tree around the patch opening also influenced tree growth,as residual trees more to the North,South,and East sides exhibited significantly higher mean BAI than trees on the West side of the patch openings(p<0.001).However,distance from the patch opening border did not significantly affect the mean BAI(p=0.522).In all treatments,dominant and co-dominant trees exhibited higher BAI than intermediate and overtopped trees,indicating that tree canopy position significantly influenced tree growth(p<0.001).Understanding how residual trees grow after these silvicultural treatments is crucial for thoroughly assessing their efficacy with longleaf pine.This study's findings will enhance our understanding of stand dynamics during stand conversion and help land managers anticipate the growth of longleaf pine into larger size categories after single tree and patch cuttings.
基金the Fundamental Research Funds for the Central Universities(Grant No.2572021DT04)the National Natural Science Foundation of China(Grant No.31770656).
文摘Nitrogen and phosphorus (NP) deposition can change the nutrient input of forest ecosystems. The effects of NP deposition on soil aggregate need to be analyzed to propose effective environmental management strategies. In this study, representative Korean pine mixed forests and Korean pine plantations in northeastern China were selected. Soil samples were sieved to obtain four different particle sizes of soil aggregates (> 2, 2–0.25, 0.25–0.053, and < 0.053 mm). Four NP treatments were applied to simulate N and P deposition, and an indoor incubation experiment was conducted over a period of 360 d. Total nitrogen, microbial nitrogen, dissolved organic nitrogen, hydrolyzed nitrogen, NH_(4)^(+)–N, NO_(3)^(−)–N content, and extracellular enzyme activities of NAG, LAP, and AP were determined. Different fractions of N responded differently to NP addition. Lower NP addition had a greater promoting effect on aggregate N compared to higher NP addition. NAG was the main extracellular enzyme affecting N in both forest types. NP addition had a greater effect on the extracellular enzyme activities of the soil aggregates from the Korean pine plantations. These results enhance our understanding of the effects of NP addition on soil nitrogen within temperate forest ecosystems.
基金financially supported by a grant from the Forest Fund of the Polish State Forests(Grant No.EZ.0290.1.16.2021).
文摘We tested the effectiveness of the gradual removal of Scots pine(Pinus sylvestris L.)in former plantations of this species in Roztocze National Park(SE Poland)to support the restoration of natural herbaceous flora and forest structure.We compared 0.5-ha study plots subjected to selective removal of pine trees with control plots excluded from any kind of human intervention for half a century.The observed changes in forest floor vegetation in the converted plots showed naturalization towards habitat-specific species.However,differences in the spatial distribution of trees between the treatment and control plots showed no universal pattern and revealed subtle but positive shifts from regular to random or clustered patterns.The mean tree diameters were higher in plots subjected to Scots pine removal,which resulted from the vigorous growth of tree species,consistent with habitat types.We conclude that forest restoration through the removal of planted trees can support the naturalization of former Scots pine plantations in protected areas.However,the selection of an appropriate method and its intensity are of vital importance.Methods that resemble typical management practices,such as selection thinning,are not always the best approach,as they may preserve or even increase the regular distribution of trees.Therefore,for restoration purposes,we recommend testing other methods that increase spatial heterogeneity,including systematic cutting or emulating natural disturbances.In addition,low-intensity thinning may not be sufficient to support the restoration of natural forest floor vegetation and the variability in forest stand structure.
基金funded by the Joint Funds for Regional Innovation and Development of the National Natural Science Foundation of China(No. U21A20244)the National Natural Science Foundation of China(No. 32071758)the National Key R&D Program of China (No.2022YFD2201000)
文摘Forest management planning faces uncertainties regarding future timber prices,tree growth,and survival.Future seed production is an additional source of uncertainty in Korean pine stands managed for the joint production of timber and edible seeds.Modern forest planning uses optimisation to determine the best possible cutting schedule.Optimisation can accommodate uncertainty by using decision rules for adaptive forest management instead of optimising cutting years and intensities.In this study,we optimised two adaptive decision rules for managing Korean pine plantations for the joint production of timber and pinecones when timber prices,tree growth,and seed production are stochastic.The first rule indicated the minimum price to sell timber,i.e.,the reservation price,as a function of the mean tree diameter and stand basal area.The second adaptive rule expressed the mean tree diameter at which cutting is optimal as a function of timber price and stand basal area.Both decision rules resulted in nearly the same mean net present value when the optimised rule was applied to 100 stochastic scenarios for future timber prices,tree growth,and seed production.The net present values were over 20% higher than those for the deterministically optimised cutting schedules under the same scenarios.Therefore,the expected economic gain from switching from deterministic to adaptive stochastic optimisation was at least 20%.The cutting years of the adaptive optima were frequently later than those indicated by the deterministic optima,and optimal adaptive harvesting often involved waiting for high timber prices.The minimum price or minimum mean diameter to sell timber was higher when the income from seeds was considered in the optimisation.The cuttings were later,and the rotations were longer in the joint production of timber and pinecones than in timber production alone.
基金supported by the USDA National Institute of Food and Agriculture,McIntire Stennis Project GEOZ0202-MS.
文摘This study evaluated the long-term growth responses of pine plantations in the Lower Coastal Plain of Florida to different site preparation(SP)treatments,including variations in bedding timing(early or late),frequency(single or double),and herbicide use(banded or broadcast pre-plant application),with or without first-year post-plant herbaceous weed control(HWC).The results showed that growth responses varied by location,primarily influenced by the effectiveness of vegetation control,especially in suppressing woody shrubs.Pre-plant herbicide treatments consistently improved growth,with broadcast applications often performing as well or better than the banded treatments.Although bedding timing and frequency influenced growth at some sites,their effects were inconsistent.Superior growth was observed in treatments combining early bedding with pre-plant herbicide,even without HWC,highlighting the critical role of effective vegetation management in enhancing the productivity of pine plantations.
基金supported by Science and Technology Foundation Project of Ministry of Science and Technology of China(2012FY112000).
文摘Based on the survey data of nine primitive broad-leaved Korean pine forest plots ranging from 1 to 10.4 ha in Heilongjiang Province,this study used the moving window method and GIS technology to analyze the variation characteristics of the spatial distribution pattern of forest biomass in each plot.We explored the minimum area that can reflect the structural and functional characteristics of the primitive broad-leaved Korean pine forest,and used computer simulation random sampling method to verify the accuracy of the minimum area.The results showed that:(1)Through the analysis of the spatial distribution raster map of biomass deviation in the plots at various scales of 10−100 m,there is a minimum area(0.64 ha)for the critical range of biomass density variation in the primitive broad-leaved Korean pine forest.This minimum area based on biomass density can indirectly reflect the comprehensive characteristics of productivity level per unit area,structure,function,and environmental quality of the primitive broad-leaved Korean pine forest community.(2)Using computer simulation random sampling,it was found that only by sampling in a specific plot larger than or equal to the minimum area can equivalent or similar results be achieved as random sampling within the plot,indicating that the minimum area determined by the moving window method is accurate.(3)The minimum area determined in this paper is an excellent indicator reflecting the complexity of community structure,which can be used for comparing changes in community structure and function before and after external disturbances,and has a good evaluation effect.This minimum area can also be used as a basis for scientific and reasonable setting of plot size in the investigation and monitoring work of broad-leaved Korean pine forests in this region,thereby achieving the goals of improving work efficiency and saving work costs.
基金support from the European Union’s Horizon 2020 research and innovation framework program under Grant No.101003590(PolarRES)funding from the Indian Institute of Technology Kharagpur and the Ministry of Education,Government of India。
文摘We show that low-level jets(LLJs)occurred in 11 out of 22 radiosonde profiles in late austral summer over the coastal region of the Amundsen Sea Embayment,with ten of the LLJs directed offshore.The LLJs had core speeds from 9 to 32 m s^(-1),jet core heights from 80 to 800 m,and were associated with strong,low-level temperature inversions.Seven of the observed offshore LLJs were reasonably simulated by the polar-optimized Weather Research and Forecasting(Polar WRF)model,with output from the model subsequently used to elucidate their generation mechanisms.This study shows that one of the offshore LLJs simulated by the Polar WRF was caused by katabatic winds,while the remaining six were caused by the enhancement of katabatic winds by synoptic forcing in response to a low-pressure system over the Bellingshausen Sea,i.e.,the offshore wind component associated with this system plays a crucial role in the enhancement of the katabatic LLJ.Examination of the Polar WRF output further shows that the LLJs extended over large areas of the Amundsen Sea Embayment,resulting in substantially enhanced near-surface wind speeds over both the Thwaites and Pine Island ice shelves,as well as the open ocean over the continental shelf.The wind-driven forcing associated with the LLJs could perhaps have important impacts on the redistribution of snow over the ice shelves significantly,as well as to affecting sea-ice and ocean circulation variability,including the transport of relatively warm water over the continental shelf to the ice shelf cavities and extension basal melting.
基金funded by the National Natural Science Foundation of China(grant number:31971527,32001126)Heilongjiang Provincial Key Research and Development Plan Guidance Projects(grant number:GZ20210009)Natural Science Foundation of Heilongjiang Province(grant number:TD2019C002).
文摘Human activities contribute to elevated nitrogen input in terrestrial ecosystems,influencing the composition of soil nutrients and microbial diversity in forest ecosystems.In this study,we built four addition treatments(0,20,40,and 80 kg ha^(−1)a^(−1)N for 6 a)at a Korean pine plantation of different soil horizons(organic(O)horizon,ranging from 0 to 10 cm,and organomineral(A)horizon,extending from 10 to 20 cm)to evaluate responses of the structure of saprophytic fungal communities.Here,80 kg ha^(−1)a^(−1)N treatment significantly decreased the community richness in soil A horizon with the Chao1 index decreasing by 12.68%.Nitrogen addition induced changes in the composition of saprophytic fungi community between the different soil horizons.The co-occurrence network and its associated topological structure were utilized to identify mycoindicators for specific fungi to both soil horizons and nitrogen addition levels.In soil O horizon,the mycoindicators included Penicillium,Trichoderma,Aspergillus,and Pseudeurotium across control,low,medium,and high nitrogen treatments.In soil A horizon,Geomyces,Cladophialophora,Penicillium,and Pseudeurotium were identified as mycoindicators.Structural equation modeling determined NH_(4)^(+)-N as the key factor driving changes in saprotrophic fungal communities.Our study aimed to screen mycoindicators that can respond to the increasing global nitrogen deposition and to assess the roles of these mycoindicators in the saprophytic fun-gal community structure within Korean pine plantations in northeast China.
基金supported by the Tomsk State University Development Program(《Priority-2030》)the Basic Project of the Federal Research Center of the Scientific Center,no.FWES-2024-0023the Russian Science Foundation(project No.23-14-20015)。
文摘The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will occur mainly at the edges of the species ranges.We focused on the responses to climate change of the drought-resistant larch(Larix sibirica)and the moisture-sensitive Siberian pine(Pinus sibirica)along the elevation gradient in the Tannu-Ola Ridge,the southern margin where those two species coexist in Siberia by using satellite data(MODIS,Landsat,and microwave),the indexes of gross(GPP)and net(NPP)primary productivity,and tree radial growth index(GI).We found that since the warming restart in the 2000s,the area of larch-dominated forests increased by~150%while the area of pine-dominated forests decreased by~10%.The Siberian pine has retreated at low elevations(<1800 m)and increased its area at higher ones.In contrast,the area of larch stands increased in both the uphill and downhill directions.Birch(Betula spp.)also increased its area at low elevations(about+120%).Since 2001,the forested area increased by~5%.A shrubification,i.e.,an increase in the area of shrubs,was observed at high elevations.The uphill rate of timberline and shrubline migration was about 0.3 m/a.Since the 2000s,vegetation NPP has increased by 13%.A notable correlation between NPP and the GI of larch and pine was found(r=0.5-0.7).At lower elevations,NPP positively correlated with precipitation and soil moisture,while air temperature and VPD(vapor pressure deficit)increase inhibited productivity.At high elevations,the effects of these variables on productivity reversed.The continuous decline of the Siberian pine forest indicates an inevitable retreat of this species at low elevations and its replacement by larch and birch.
基金The research was supported by innovation research project of Chinese Academy of Sciences (KZCX3-SW-418) and by Nature Science Foundation of Liaoning Province (20021006).
文摘Mongolian pine (Pinus sylvestiris Linnaeus var. mongolica Litvinov) as a valuable conifer tree species has been broadly introduced to the sandy land areas in 揟hree North?regions (North, northwest and northeast of China), but many problems occurred in the earliest Mongolian pine plantations in Zhanggutai, Zhangwu County, Liaoning Province (ZZL). In order to clarify the reason, comprehensive investigations were carried out on differences in structure characteristics, growth processes and ecological factors between artificial stands (the first plantation established in ZZL in 1950s) and natural stands (the origin forests of the tree species in Honghuaerji, Inner Mongolia) on sandy land. The results showed that variation of diameter-class distributions in artificial stands and natural stands could be described by Weibull and Normal distribution models, respectively. Chapman-Richards growth model was employed to reconstruct the growth process of Mongolian pine based on the data from field investigation and stem analysis. The ages of maximum of relative growth rate and average growth rate of DBH, height, and volume of planted trees were 11, 22 years, 8, 15 years and 35, 59 years earlier than those of natural stand trees, respectively. In respect of the incremental acceleration of volume, the artificial and natural stands reached their maximum values at 14 years and 33 years respectively. The quantitative maturity ages of artificial stands and natural stands were 43 years and 102 years respectively. It was concluded that the life span of the Mongolian pine trees in natural stands was about 60 years longer than those in artificial stands. The differences mentioned above between artificial and natural Mongolian pine forests on sandy land were partially attributed to the drastic variations of ecological conditions such as latitude, temperature, precipitation, evaporation and height above sea level. Human beings' disturbances and higher density in plantation forest may be ascribed as additional reasons. Those results may be potentially useful for the management and afforestation of Mongolian pine plantations on sandy land in arid and semi-arid areas.
