The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or ...The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or missing annual rings is highly possible.In this study,we analyzed the radial growth of Siberian larch(Larix sibirica)in the Hongshanzui area of the Altai Mountains,China.The overall missing ring rate at the sampling point was 2.39%,with years with the highest missing rings since meteorological site data were available(1960)identified as 1960,1961,1971,1973,1985,1987,and 1995.Radial growth in high altitudes was mainly affected by temperatures in May and June(average temperature,average minimum temperature,and average maximum temperature).Frequent periods of freezing may lead to missing annual rings.However,while Larix sibirica shows resilience after prolonged freezing temperatures,it still requires time for the trees to return to normal growth levels.展开更多
Although Pinus sibirica and Pinus koraiensis are resistant to cold or low temperatures in the cold temperate regions of the northern hemisphere,the former has a stronger cold resistance.Research has been limited to th...Although Pinus sibirica and Pinus koraiensis are resistant to cold or low temperatures in the cold temperate regions of the northern hemisphere,the former has a stronger cold resistance.Research has been limited to the comparison of physiological responses of the two species to cold stress.In this study,5-year-old seedlings of P.sibirica and P.koraiensis were subjected to six temperature treatments,[20℃(control),0℃,-20℃,-40℃,-60℃,and-80℃],under different stress periods(6,12,24,and 48 h).The results showed that differences in each physiological index were significant between P.sibirica and P.koraiensis,except for the permeability of cell membranes,reactive oxygen species,proline and soluble proteins.An ANOVA test indicated that there were extreme differences among the temperatures for each index,stress time and temperature 9 time for most indices.All indices showed a similar trend for P.sibirica and P.koraiensis with decreasing temperature or the extension of stress time.Soluble sugars and proline increased at 0 to-20℃and then remained unchanged with temperature decline.Other indices showed an increase from 20 to-20℃,stable from-20 to-40℃and a decrease from-40 to-80℃.All the indices increased and then declined along with the prolonged cold stress time,except for the control.From 0 to-40℃,the permeability of cell membranes,relative conductivity,reactive oxygen species and malonaldehyde of P.koraiensis seedlings were higher than in P.sibirica,but superoxide dismutase,peroxidase,catalase activity and soluble sugars,proline,and soluble proteins content emerged as opposite.This study compared the physiological mechanism responses to cold stress between P.sibirica and P.koraiensis to provide the basis for the introduction,distribution,and genetic improvement of these coniferous species.展开更多
Siberian Pine （Pinus sibirica） is an ecologically and eco-nomically important species in pristine forests throughout northern Rus-sia. Four provenances of P. sibirica were introduced from Mongolia and Russia to the ...Siberian Pine （Pinus sibirica） is an ecologically and eco-nomically important species in pristine forests throughout northern Rus-sia. Four provenances of P. sibirica were introduced from Mongolia and Russia to the Greater Xing’an Range （the Daxing’anling）, northeast China in 1993. The aim of this research was to study genetic variation and selection of the introduced four Pinus sibirica provenances. Heights （H）, basal diameters （BD）, survival rates （SR） and crown lengths （CL） of different families were measured as primary outcomes in different growth years. Results of data analyses demonstrated high coefficients of phenotypic variation （PCV） and heritability （H2） for H, BD and CL at 18 years after introduction. PCV and H2 increased with age. Correlations of＆amp;nbsp;growth traits between any two growth years were all significantly positive, but the correlation coefficient was smaller when the growth year interval was larger. Correlations between H and the original environment factors decreased gradually, indicating that with long-term subsistence in the new environment, the influence of the source environment declined. Colligation of multiple traits to estimate provenances showed that Novosibirsk, Tomsk, and Altai Mountains had higher survival rates and biomass, and proved more suitable for introduction and plantation in the Greater Xing’an Range in China.展开更多
Siberian apricot(Prunus sibirica L.)is a traditional nut tree species in East Asia and Siberia and is a possible contribution to healthy diets.However,it has attracted little research attention and information on the ...Siberian apricot(Prunus sibirica L.)is a traditional nut tree species in East Asia and Siberia and is a possible contribution to healthy diets.However,it has attracted little research attention and information on the nutritional value of its kernel is limited.In this study,the profile,nutritional value and variation of amino acids were investigated in eight provenances.The kernels contained29×10-2 g/g protein and were rich in glutamic acid(26.5%),aspartic acid(11.3%)and arginine(10.1%).They showed higher essential amino acids(EAA)than similar protein values for almonds.The variation coefficients of amino acids ranged from 3.8 to 43.7%,and the levels of seven amino acids were significantly different among the eight provenances.The proportion of essential amino acids to total amino acids and amino acid score were also quite different.Protein was negatively correlated with some amino acids and protein quality values.In conclusion,there were two superior provenances(Wanjiagou and Horinger County)with high EAA contents and protein quality,and could be used in the large-scale development of this species.展开更多
The objective of this study is to investigate the potential causes of widespread Larix sibirica Ledeb.mortality observed in the Khentii massif of northern Mongolia.The ratio of deadwood to living trees in affected sta...The objective of this study is to investigate the potential causes of widespread Larix sibirica Ledeb.mortality observed in the Khentii massif of northern Mongolia.The ratio of deadwood to living trees in affected stands in the Goricho region,the southernmost study site situated close to the Gobi Desert,was as high as 3.6:1.Moisture fluctuations monitored over 2 years using electrical impedance spectrometry revealed that the Goricho study site had higher soil moisture levels than the two less affected sites Barun Bayan and Dzun Bayan.High soil moisture was recorded in an area characterized by highly skeletal soils,ones with more than 35%by volume of rock fragments,and comparatively shallow soil horizons,from valley to mountains.The layer of permafrost influencing hydrogeological processes is much deeper in the Goricho region compared to the undisturbed study sites.Redundancy analysis confirmed a significant number of dead L.sibirica on sites with developed soils.Live forest stands,however damaged,grow in this region on well-drained scree slopes or on rocky bastions.The mass mortality observed for L.sibirica may be directly linked to accelerated permafrost thaw in the area bordered by the Tuul and the Terelj Rivers.Our assumption is that L.sibirica root system necrosis occurred as a result of long-term waterlogging of developed soils with high spatial heterogeneity,normally able to absorb high quantities of groundwater.The areas unaffected were scree fields and rocky bastions characterized by adequate drainage.All of our findings support the primary stages of large-scale permafrost thaw,i.e.,correlating increases in soil moisture with increasing permafrost active layer thickness.展开更多
Nitraria sibirica Pall. is a shrub that grows in saline-alkali soil and has traditional medicinal value and potential commercial value. The objectives of this study include induction and multiplication of callus, esta...Nitraria sibirica Pall. is a shrub that grows in saline-alkali soil and has traditional medicinal value and potential commercial value. The objectives of this study include induction and multiplication of callus, establishment of a suspension cell line, and isolation of protoplasts from cell suspensions. Murashige and Skoog (MS) medium was used for callus induction from mature seeds of N. sibirica. Seed-derived calluses were further multiplied on MS medium augmented with 0.5 mg L-1 6-benzylaminopurine (6-BA) and 1.0 mg L-1 2,4-dichlorophenoxy (2,4-D) acetic acid. Suspension cultures of N. sibirica were initiated by transferring friable calli to the same liquid multiplication medium. Characterization of the suspension culture was assessed based on fresh mass, dry mass, cell viability and pH value of the culture. A typical growth curve was observed after inoculating 1.5 g of callus in 40 mL liquid medium, including a lag phase, an exponential growth phase, a stationary phase, and a negative acceleration phase. The effect of factors such as pre-plasmolysis, enzyme combination, enzymolysis time and mannitol concentration, on the isolation of cell-derived protoplasts were evaluated to determine the usefulness of suspension cultures. The maximum yield (9.79 x 10(6) cells/g) and highest viability (79.97%) of protoplast were reached when approximately 1 g of cell suspension (cultured for 6 days) was inoculated for 12 h in cell and protoplast washing solution made of 0.8 mol L-1 mannitol mixture solution, cellulose onozuka R-10 2% (w/v), hemicellulose 0.2%, macerozyme R-10 1%, and pectolyase Y-23 0.5%. Protoplast yield was significantly influenced by pre-plasmolysis and cellulose onozuka R-10 (P < 0.05).展开更多
Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as ...Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.展开更多
For evaluating microbial community changes in a Siberian larch stand disturbed by forest fire or clearcutting,357 clones were randomly selected and sequenced using a culture-independent approach and 16S rRNA sequencin...For evaluating microbial community changes in a Siberian larch stand disturbed by forest fire or clearcutting,357 clones were randomly selected and sequenced using a culture-independent approach and 16S rRNA sequencing to characterize the bacterial composition and diversity from the different disturbed Siberian larch stands.Interestingly,the burned larch stand had an increase in the relative amounts of b-proteobacteria and Firmicutes and a decrease in Acidobacteria,while Gemmatimonadetes increased Verrucomicrobia decreased in the harvested larch stand.Microbial diversity and richness were higher in the undisturbed larch stand than the disturbed(burned or clear-cut)larch stands,and the influence of clear-cutting was more negative than that of the forest fire.This study indicates that evaluating the microbial diversity of undisturbed,burned,and clear-cutting Siberian larch stands provides information about the impact of forest disturbances on soil microbial communities,which may be helpful for understanding and evaluating soil health and devising reafforestation strategies for larch.展开更多
By investigation, studying and discussion for 9 years, the determination that it should be Pinus sibirica growing in the Mohe county, Daxing'anling Mountains area, China, rather thanpinus koraiensis there, is made...By investigation, studying and discussion for 9 years, the determination that it should be Pinus sibirica growing in the Mohe county, Daxing'anling Mountains area, China, rather thanpinus koraiensis there, is made to correct a false argument in some works from 1950s' till now that Pinus koraiensis area limit reach Daxing'anling Mountain. The results are as follows: (1) The species so called as Pinus koraiensis found in northwest of Daxing'anling Mountain is Pinus Sibirica indeed; There arc no natural distribution of Pinus Koraiensis in Daxing'anling Mountain. Its northwest area limit only reach Shcngshan, Aihui county; (3) There is about 500km of space between the area limits of Pinus koraiensis and that of Pinus sibirica, no mixed growing area. According to above, a sketch map is made to describe different area limit of the two species at Daxing'anling Mountain and nearby.展开更多
In recent decades,the rapid climate warming in polar and alpine regions has been accompanied by an expan-sion of shrub vegetation.However,little is known about how changes in shrub distribution will change as the dist...In recent decades,the rapid climate warming in polar and alpine regions has been accompanied by an expan-sion of shrub vegetation.However,little is known about how changes in shrub distribution will change as the distribution of tree species and snow cover changes as temperatures rise.In this work,we analyzed the main environmental factors influencing the distribution and structure of Juniperus sibir-ica,the most common shrub species in the Southern Ural Mountains.Using mapping and digital elevation models,we demonstrated that J.sibirica forms a well-defined vegeta-tion belt mainly between 1100 and 1400 m a.s.l.Within this zone,the abundance and cover of J.sibirica are influenced by factors such as rockiness,slope steepness,water regime and tree(Picea obovata)cover.An analysis of data spanning the past 9 years revealed an upward shift in the distribution of J.sibirica with a decrease in its area.The primary limit-ing factors for the distribution of J.sibirica were the removal of snow cover by strong winter winds and competition with trees.As a consequence of climatic changes,the tree line and forest limit have shifted upward,further restricting the distribution of J.sibirica to higher elevations where com-petition for light with trees is reduced and snow cover is sufficiently deep.展开更多
Climate has changed sufficiently over the last 150 years and forced out upper treeline advance at the most studied sites around the world.The rate of advance has been extremely variable–from tens to hundreds meters i...Climate has changed sufficiently over the last 150 years and forced out upper treeline advance at the most studied sites around the world.The rate of advance has been extremely variable–from tens to hundreds meters in altitude.This is because the degree at which tree frontal populations respond to climate change depends on the complex interaction of biological and physical factors.The resulting stand pattern is the consequence of the interaction between dispersal and survival functions.A few publications have addressed the question of how this pattern is generated.In order to understand how the spatial structure of tree stands was formed at the upper limit of their distribution in the Ural Mountains,we assessed the distance and direction of dispersal of offspring from maternal individuals.We found that in frontal Larix sibirica Ledeb.populations,‘effective’dispersal of offspring ranges from 3 to 758 m(with a median of 20–33 m in open forest and 219 m in single-tree tundra in the Polar Urals and 107 m in open forest in the Northern Urals).We revealed that most of the offspring effectively dispersed not only in the direction of the prevailing winds,but also in the opposite direction up the slope,and the distance can reach 500–760 m.The data obtained can be used to develop an individual-based model which is capable of simulating in detail the dynamics of tree stands at the upper limit of their growth and reliably predicting the future position and pattern of treeline ecotone as growth conditions continue to improve in the face of observed climate change.展开更多
基金supported by the Natural Science Foundation of Xinjiang Uigur Autonomous Region−Science Fund for Distinguished Young Scholars(2022D01E105)the Natural Key Research and Development Program(Inter-governmental Key and Special Project,2023YFE0102700)+2 种基金Tianshan Talent Training Program−Young Scientific and Technological Innovation Talent(2023TSYCCX0076)the Science and Technology Development Fund Project of Institute of Desert Meteorology,China Meteorological Administration(KJFZ202306,KJFZ202406)Xinjiang Regional collaborative innovation project(2022E01045)。
文摘The physiological structure and growth of trees in extreme environments(freezing temperatures,prolonged drought,wildfires,pest infestations,and diseases)can be inhibited,including radial growth,and stagnant growth or missing annual rings is highly possible.In this study,we analyzed the radial growth of Siberian larch(Larix sibirica)in the Hongshanzui area of the Altai Mountains,China.The overall missing ring rate at the sampling point was 2.39%,with years with the highest missing rings since meteorological site data were available(1960)identified as 1960,1961,1971,1973,1985,1987,and 1995.Radial growth in high altitudes was mainly affected by temperatures in May and June(average temperature,average minimum temperature,and average maximum temperature).Frequent periods of freezing may lead to missing annual rings.However,while Larix sibirica shows resilience after prolonged freezing temperatures,it still requires time for the trees to return to normal growth levels.
基金financially supported by National Key Research and Development Program of China(2017YFD0600601)
文摘Although Pinus sibirica and Pinus koraiensis are resistant to cold or low temperatures in the cold temperate regions of the northern hemisphere,the former has a stronger cold resistance.Research has been limited to the comparison of physiological responses of the two species to cold stress.In this study,5-year-old seedlings of P.sibirica and P.koraiensis were subjected to six temperature treatments,[20℃(control),0℃,-20℃,-40℃,-60℃,and-80℃],under different stress periods(6,12,24,and 48 h).The results showed that differences in each physiological index were significant between P.sibirica and P.koraiensis,except for the permeability of cell membranes,reactive oxygen species,proline and soluble proteins.An ANOVA test indicated that there were extreme differences among the temperatures for each index,stress time and temperature 9 time for most indices.All indices showed a similar trend for P.sibirica and P.koraiensis with decreasing temperature or the extension of stress time.Soluble sugars and proline increased at 0 to-20℃and then remained unchanged with temperature decline.Other indices showed an increase from 20 to-20℃,stable from-20 to-40℃and a decrease from-40 to-80℃.All the indices increased and then declined along with the prolonged cold stress time,except for the control.From 0 to-40℃,the permeability of cell membranes,relative conductivity,reactive oxygen species and malonaldehyde of P.koraiensis seedlings were higher than in P.sibirica,but superoxide dismutase,peroxidase,catalase activity and soluble sugars,proline,and soluble proteins content emerged as opposite.This study compared the physiological mechanism responses to cold stress between P.sibirica and P.koraiensis to provide the basis for the introduction,distribution,and genetic improvement of these coniferous species.
基金supported by grants Seedling Technology Rules of Siberia pine(No.2012-LY-183)
文摘Siberian Pine （Pinus sibirica） is an ecologically and eco-nomically important species in pristine forests throughout northern Rus-sia. Four provenances of P. sibirica were introduced from Mongolia and Russia to the Greater Xing’an Range （the Daxing’anling）, northeast China in 1993. The aim of this research was to study genetic variation and selection of the introduced four Pinus sibirica provenances. Heights （H）, basal diameters （BD）, survival rates （SR） and crown lengths （CL） of different families were measured as primary outcomes in different growth years. Results of data analyses demonstrated high coefficients of phenotypic variation （PCV） and heritability （H2） for H, BD and CL at 18 years after introduction. PCV and H2 increased with age. Correlations of＆amp;nbsp;growth traits between any two growth years were all significantly positive, but the correlation coefficient was smaller when the growth year interval was larger. Correlations between H and the original environment factors decreased gradually, indicating that with long-term subsistence in the new environment, the influence of the source environment declined. Colligation of multiple traits to estimate provenances showed that Novosibirsk, Tomsk, and Altai Mountains had higher survival rates and biomass, and proved more suitable for introduction and plantation in the Greater Xing’an Range in China.
基金This study is supported by Fundamental Research Funds for the Central Non-profit Research Institution of Chinese Academy of Forestry (CAFYBB2017ZA004-4)
文摘Siberian apricot(Prunus sibirica L.)is a traditional nut tree species in East Asia and Siberia and is a possible contribution to healthy diets.However,it has attracted little research attention and information on the nutritional value of its kernel is limited.In this study,the profile,nutritional value and variation of amino acids were investigated in eight provenances.The kernels contained29×10-2 g/g protein and were rich in glutamic acid(26.5%),aspartic acid(11.3%)and arginine(10.1%).They showed higher essential amino acids(EAA)than similar protein values for almonds.The variation coefficients of amino acids ranged from 3.8 to 43.7%,and the levels of seven amino acids were significantly different among the eight provenances.The proportion of essential amino acids to total amino acids and amino acid score were also quite different.Protein was negatively correlated with some amino acids and protein quality values.In conclusion,there were two superior provenances(Wanjiagou and Horinger County)with high EAA contents and protein quality,and could be used in the large-scale development of this species.
基金supported by funding provided by the project CEITEC 2020(LQ1601)the Research Fund of the FFWT at Mendel University in Brno(Reg.Number:LDF_PSV_2017008)
文摘The objective of this study is to investigate the potential causes of widespread Larix sibirica Ledeb.mortality observed in the Khentii massif of northern Mongolia.The ratio of deadwood to living trees in affected stands in the Goricho region,the southernmost study site situated close to the Gobi Desert,was as high as 3.6:1.Moisture fluctuations monitored over 2 years using electrical impedance spectrometry revealed that the Goricho study site had higher soil moisture levels than the two less affected sites Barun Bayan and Dzun Bayan.High soil moisture was recorded in an area characterized by highly skeletal soils,ones with more than 35%by volume of rock fragments,and comparatively shallow soil horizons,from valley to mountains.The layer of permafrost influencing hydrogeological processes is much deeper in the Goricho region compared to the undisturbed study sites.Redundancy analysis confirmed a significant number of dead L.sibirica on sites with developed soils.Live forest stands,however damaged,grow in this region on well-drained scree slopes or on rocky bastions.The mass mortality observed for L.sibirica may be directly linked to accelerated permafrost thaw in the area bordered by the Tuul and the Terelj Rivers.Our assumption is that L.sibirica root system necrosis occurred as a result of long-term waterlogging of developed soils with high spatial heterogeneity,normally able to absorb high quantities of groundwater.The areas unaffected were scree fields and rocky bastions characterized by adequate drainage.All of our findings support the primary stages of large-scale permafrost thaw,i.e.,correlating increases in soil moisture with increasing permafrost active layer thickness.
基金supported by the National Science&Technology Pillar Program during the 12th Five-year Plan Period(2011AA10020102)
文摘Nitraria sibirica Pall. is a shrub that grows in saline-alkali soil and has traditional medicinal value and potential commercial value. The objectives of this study include induction and multiplication of callus, establishment of a suspension cell line, and isolation of protoplasts from cell suspensions. Murashige and Skoog (MS) medium was used for callus induction from mature seeds of N. sibirica. Seed-derived calluses were further multiplied on MS medium augmented with 0.5 mg L-1 6-benzylaminopurine (6-BA) and 1.0 mg L-1 2,4-dichlorophenoxy (2,4-D) acetic acid. Suspension cultures of N. sibirica were initiated by transferring friable calli to the same liquid multiplication medium. Characterization of the suspension culture was assessed based on fresh mass, dry mass, cell viability and pH value of the culture. A typical growth curve was observed after inoculating 1.5 g of callus in 40 mL liquid medium, including a lag phase, an exponential growth phase, a stationary phase, and a negative acceleration phase. The effect of factors such as pre-plasmolysis, enzyme combination, enzymolysis time and mannitol concentration, on the isolation of cell-derived protoplasts were evaluated to determine the usefulness of suspension cultures. The maximum yield (9.79 x 10(6) cells/g) and highest viability (79.97%) of protoplast were reached when approximately 1 g of cell suspension (cultured for 6 days) was inoculated for 12 h in cell and protoplast washing solution made of 0.8 mol L-1 mannitol mixture solution, cellulose onozuka R-10 2% (w/v), hemicellulose 0.2%, macerozyme R-10 1%, and pectolyase Y-23 0.5%. Protoplast yield was significantly influenced by pre-plasmolysis and cellulose onozuka R-10 (P < 0.05).
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2019D01C069)Natural Science Foundation of Xinjiang University(No.62031224614)。
文摘Nitraria sibirica Pall.is an important shrub with a strong salt-alkali tolerance,but the mechanism underlying this tolerance remains obscure.In this study,N.sibirica,with salt-sensitive Vigna radiata(Linn.)Wilczek as the control,was subjected to transient salt stress(100 mM NaCl),alkali stress(50 mM Na_(2)CO_(3)),and osmotic stress(175 mM mannitol).The ionic fluxes of Na^(+)and K^(+)in the root apical region were measured.Results show that,under salt and alkali stress,N.sibirica roots exhibited higher capacities to limit Na+influx and reduce K+efflux,thereby resulting in lower Na^(+)/K^(+)ratios compared with V.radiata roots.Alkali stress induced stronger Na^(+)influx and K+efflux in the root salt stress treatment;Na^(+)influx was mainly observed in the root cap,while K^(+)efflux was mainly observed in the elongation zone.While under osmotic stress,N.sibirica roots showed stronger Na+efflux and weaker K+efflux than V.radiata roots.Na+efflux was mainly observed in the root elongation zone,while K+efflux was in the root cap.These results reveal the ionic strategy of N.sibirica in response to transient salt,alkali,and osmotic stresses through the regulation of Na+/K+flux homeostasis.
基金supported by Daegu University Research Grant(No.20130508)
文摘For evaluating microbial community changes in a Siberian larch stand disturbed by forest fire or clearcutting,357 clones were randomly selected and sequenced using a culture-independent approach and 16S rRNA sequencing to characterize the bacterial composition and diversity from the different disturbed Siberian larch stands.Interestingly,the burned larch stand had an increase in the relative amounts of b-proteobacteria and Firmicutes and a decrease in Acidobacteria,while Gemmatimonadetes increased Verrucomicrobia decreased in the harvested larch stand.Microbial diversity and richness were higher in the undisturbed larch stand than the disturbed(burned or clear-cut)larch stands,and the influence of clear-cutting was more negative than that of the forest fire.This study indicates that evaluating the microbial diversity of undisturbed,burned,and clear-cutting Siberian larch stands provides information about the impact of forest disturbances on soil microbial communities,which may be helpful for understanding and evaluating soil health and devising reafforestation strategies for larch.
文摘By investigation, studying and discussion for 9 years, the determination that it should be Pinus sibirica growing in the Mohe county, Daxing'anling Mountains area, China, rather thanpinus koraiensis there, is made to correct a false argument in some works from 1950s' till now that Pinus koraiensis area limit reach Daxing'anling Mountain. The results are as follows: (1) The species so called as Pinus koraiensis found in northwest of Daxing'anling Mountain is Pinus Sibirica indeed; There arc no natural distribution of Pinus Koraiensis in Daxing'anling Mountain. Its northwest area limit only reach Shcngshan, Aihui county; (3) There is about 500km of space between the area limits of Pinus koraiensis and that of Pinus sibirica, no mixed growing area. According to above, a sketch map is made to describe different area limit of the two species at Daxing'anling Mountain and nearby.
文摘In recent decades,the rapid climate warming in polar and alpine regions has been accompanied by an expan-sion of shrub vegetation.However,little is known about how changes in shrub distribution will change as the distribution of tree species and snow cover changes as temperatures rise.In this work,we analyzed the main environmental factors influencing the distribution and structure of Juniperus sibir-ica,the most common shrub species in the Southern Ural Mountains.Using mapping and digital elevation models,we demonstrated that J.sibirica forms a well-defined vegeta-tion belt mainly between 1100 and 1400 m a.s.l.Within this zone,the abundance and cover of J.sibirica are influenced by factors such as rockiness,slope steepness,water regime and tree(Picea obovata)cover.An analysis of data spanning the past 9 years revealed an upward shift in the distribution of J.sibirica with a decrease in its area.The primary limit-ing factors for the distribution of J.sibirica were the removal of snow cover by strong winter winds and competition with trees.As a consequence of climatic changes,the tree line and forest limit have shifted upward,further restricting the distribution of J.sibirica to higher elevations where com-petition for light with trees is reduced and snow cover is sufficiently deep.
基金supported by the Russian Center for Scientific Information under grant RFBR–21–54–12016 for the sampling and treating of collected materialsby the Russian Scientific Foundation under grant RSF-24–14-00206 for data analysis and preparation of the manuscript.
文摘Climate has changed sufficiently over the last 150 years and forced out upper treeline advance at the most studied sites around the world.The rate of advance has been extremely variable–from tens to hundreds meters in altitude.This is because the degree at which tree frontal populations respond to climate change depends on the complex interaction of biological and physical factors.The resulting stand pattern is the consequence of the interaction between dispersal and survival functions.A few publications have addressed the question of how this pattern is generated.In order to understand how the spatial structure of tree stands was formed at the upper limit of their distribution in the Ural Mountains,we assessed the distance and direction of dispersal of offspring from maternal individuals.We found that in frontal Larix sibirica Ledeb.populations,‘effective’dispersal of offspring ranges from 3 to 758 m(with a median of 20–33 m in open forest and 219 m in single-tree tundra in the Polar Urals and 107 m in open forest in the Northern Urals).We revealed that most of the offspring effectively dispersed not only in the direction of the prevailing winds,but also in the opposite direction up the slope,and the distance can reach 500–760 m.The data obtained can be used to develop an individual-based model which is capable of simulating in detail the dynamics of tree stands at the upper limit of their growth and reliably predicting the future position and pattern of treeline ecotone as growth conditions continue to improve in the face of observed climate change.
