The development of the mining industry has led to the appearance in many parts of the world of vast technogenic territories from which toxic heavy metals enter the environment and food chains.Physical,chemical,and bio...The development of the mining industry has led to the appearance in many parts of the world of vast technogenic territories from which toxic heavy metals enter the environment and food chains.Physical,chemical,and biological methods of cleaning industrial land due to technological complexity and hi gh cost are relatively little used on a large scale.Natural forest overgrowth of mining sites and the removal of heavy metals by woody plants can be an effective form of recovery.Therefore,the study of this process is of significant scientific and practical interest.The analysis of the annual growth in height and width of the annual rings of the stem of Scots pine(Pinus sylvestris L.) in 2004-2019 was made on the territory of the Uchalinsky mining and processing plant(South Ural,Russia) contaminated with heavy metals.Relatively hi gh concentrations of copper and zinc were found in soils,roots,bark,young shoots,comparable to exceeding the maximum allowable concentrations.Despite the spatial uniformity of the heavy metal content in the stands,the tree samples significantly differed in terms of annual growth.Results suggest that the lack of nutrients and not stress from exposure to heavy metals is the main reason for relatively low growth rates on slopes of industrial wastes.It was confirmed by studying the annual growth in height of the undergrowth in habitats with different soil cover conservation.The data prove the relatively high potential of Scots pine for the natural recovery of industrial lands polluted with heavy metals by mining enterprises.展开更多
Changes in annual radial growth is an important indication of climate change. Dendroclimatology studies in northern China have focused on linear statistical analysis,but lacking studies based on the process of ring fo...Changes in annual radial growth is an important indication of climate change. Dendroclimatology studies in northern China have focused on linear statistical analysis,but lacking studies based on the process of ring formation to clarify the radial growth of trees. Tree-ring width standard chronology(STD) was established using samples of Larix principis-rupprechtii collected at 2303 m altitude on Luya Mountain. Using the Vaganov-Shashkin(VS) model to simulate growth and development, the internal physiological mechanism of radial growth is identified. It was concluded that:(1) the growing season of L. principis-rupprechtii was May to September;(2) soil moisture was a significant factor in the early and late growing seasons, and temperature was the dominant factor in its main growth period;and(3) formation of narrow ring widths was closely related to drought stress, the development of wide ring widths will be restricted by increasing future temperatures. The VS model is applicable for radial growth simulation of subalpine coniferous forests and for guiding the cultivation of local tree species in the future.展开更多
Background: Stem radial growth in forests is not uniform. Rather, it is characterized by periods of relatively fast or slow growth, or sometimes no growth at all. These fluctuations are generally a function of varying...Background: Stem radial growth in forests is not uniform. Rather, it is characterized by periods of relatively fast or slow growth, or sometimes no growth at all. These fluctuations are generally a function of varying environmental conditions(e.g. water availability) and, importantly, will also be associated with adjustments in proprties in the wood formed. Stand level conditions and forest management, particularly thinning and stand density will, thowever, also have a major influence on patterns of growth variation. We explore how different thinning histories and/or stand densities influence these dynamics of tree growth in the important commercial plantation species Pinus radiata D. Don.Methods: Daily stem size change was measured using electronic point dendrometers over two growing seasons on P. radiata trees at two sites, subjected to different thinning regimes. Timing, rates and periodicity of annual growth were calculated from these data.Results: Greater overall cross-sectional growth in thinned plots was driven mainly by two dynamics. First, the cessation of seasonal growth occurred at least 3 weeks later in the stands in which thinning had taken place. There was no difference between thinned/unthinned stands, however, in the timing of growth onset. Second, within the longer season, trees in thinned plots had more growth days(as much as 20% more) than unthinned plots. The rates of growth on days when growth occurred were not different, however. In this context, it is notable that in trees in the unthinned plots experiencing the most severe competition there were strong "pulses" of growth following drought-breaking rainfall events. Unthinned plots at high stand densities also maintained a smaller(but consistent) zone of dividing cells throughout the season than thinned plots.Conclusions: In Pinus radiata growing under conditions as in our study, conditions late in summer, particularly drought, have an important effect on the timing of cessation of growth. Early season temperature appears to have no effect in determining timing of annual growth. Limiting conditions during the season reduce growing duration, and thus total growth, more in unthinned stands than thinned stands. These findings are valuable in developing new generations of fine-scale growth and wood property models.展开更多
ＡｖｅｒａｇｅＡｎｎｕａｌＧｒｏｗｔｈｏｆＧＤＰｄｕｒｉｎｇｔｈｅＥｉｇｈｔｈＦｉｖｅ－ＹｅａｒＰｌａｎＰｅｒｉｏｄＳｔａｔｅＳｔａｔｉｓｔｉｃａｌＢｕｒｅａｕＳｏｕｒｃｅ：ＳｔａｔｅＳｔａｔｉｓｔｉｃａｌＢｕｒｅａ...ＡｖｅｒａｇｅＡｎｎｕａｌＧｒｏｗｔｈｏｆＧＤＰｄｕｒｉｎｇｔｈｅＥｉｇｈｔｈＦｉｖｅ－ＹｅａｒＰｌａｎＰｅｒｉｏｄＳｔａｔｅＳｔａｔｉｓｔｉｃａｌＢｕｒｅａｕＳｏｕｒｃｅ：ＳｔａｔｅＳｔａｔｉｓｔｉｃａｌＢｕｒｅａｕ．Average Annual Growth of GDP d...展开更多
Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential respons...Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential responses of plants to the changes in rainfall regimes, such as rainfall intensity and duration, and length of dry intervals. In this study, we investigated the effects of different rainfall patterns（e.g. small rainfall event with high frequency and large rainfall event with low frequency） on biomass, growth characteristics and vertical distribution of root biomass of annual plants in Horqin Sandy Land, Inner Mongolia of China during the growing season（from May to August） of 2014. Our results showed that the rainfall patterns, independent of total rainfall amount, exerted strong effects on biomass, characteristics of plant growth and vertical distribution of root biomass. Under a constant amount of total rainfall, the aboveground biomass（AGB）, belowground biomass（BGB）, plant cover, plant height, and plant individual and species number increased with an increase in rainfall intensity. Changes in rainfall patterns also altered the percentage contribution of species biomass to the total AGB, and the percentage of BGB at different soil layers to the total BGB. Consequently, our results indicated that increased rainfall intensity in future may increase biomass significantly, and also affect the growth characteristics of annual plants.展开更多
The research on the characteristic frequency of precipitation is a great significance for guiding regional agricultural planning, water conservancy project designs, and drought and flood control. Droughts and floods o...The research on the characteristic frequency of precipitation is a great significance for guiding regional agricultural planning, water conservancy project designs, and drought and flood control. Droughts and floods occurred in northern Weihe Loess Plateau, affecting growing and yield of winter wheat in the area. Based on the daily precipitation data of 29 meteorological stations from 1981 to 2012, this study is to address the analysis of three different frequencies of annual precipitation at 5%, 50%, and 95%, and to determine the amount of rainfall excess and water shortage during seven growth stages of winter wheat at 5%, 10%, and 20% frequencies, respectively. Pearson type III curve was selected for this study to analyze the distribution frequency of annual rainfall and rainfall amount following seven growth stages of winter wheat crop in 29 stations of Northern Weihe loess plateau. As a result of our study, annual precipitation is gradually increasing from southwest to northeast of Northern Weihe loess plateau. The highest amount of annual precipitation occurred in the Baoji area and the lowest precipitation covered by the northwest area of Northern Weihe loess plateau. Moreover, the amount of rainfall of seven growth stages indicates that excessive rainfall occurs not only in the first stage (sowing to tillering) and seventh stage (flowering to ripening) but also in second stage (tillering to wintering). In the seventh stage, a large amount of excessive rainfall occurred in Changwu, Bin, Qianyang, Fengxiang, Baojiqu, and Baojixian. Moreover, water shortage is distributed in the third stage (from wintering to greening), the fourth stage (from greening to jointing), the fifth stage (from jointing to heading), and the sixth stage (from heading to flowering). Furthermore, the worst water shortages occurred in Hancheng, Heyang, Chengcheng, Pucheng, Dali, Tongchuan, and Fuping in the fourth stage (greening to jointing stage). Even though we study the crop water requirement under extreme rainfall conditions, the amount of rainwater still supply inadequate in some parts of the winter wheat growth stage. Therefore, this study provides main clues for the next step to study the irrigation water needs of winter wheat crops and to reduce agricultural risks in 29 counties in the northern loess plateau and other regions.展开更多
文摘The development of the mining industry has led to the appearance in many parts of the world of vast technogenic territories from which toxic heavy metals enter the environment and food chains.Physical,chemical,and biological methods of cleaning industrial land due to technological complexity and hi gh cost are relatively little used on a large scale.Natural forest overgrowth of mining sites and the removal of heavy metals by woody plants can be an effective form of recovery.Therefore,the study of this process is of significant scientific and practical interest.The analysis of the annual growth in height and width of the annual rings of the stem of Scots pine(Pinus sylvestris L.) in 2004-2019 was made on the territory of the Uchalinsky mining and processing plant(South Ural,Russia) contaminated with heavy metals.Relatively hi gh concentrations of copper and zinc were found in soils,roots,bark,young shoots,comparable to exceeding the maximum allowable concentrations.Despite the spatial uniformity of the heavy metal content in the stands,the tree samples significantly differed in terms of annual growth.Results suggest that the lack of nutrients and not stress from exposure to heavy metals is the main reason for relatively low growth rates on slopes of industrial wastes.It was confirmed by studying the annual growth in height of the undergrowth in habitats with different soil cover conservation.The data prove the relatively high potential of Scots pine for the natural recovery of industrial lands polluted with heavy metals by mining enterprises.
基金supported by Alpine timberline fluctuations and the response to climate change at centennial to millennial time scales in the Qinling Mountains (no.42371072)a General Programfrom the Natural Science Foundation of Shaanxi Province (no.2014JQ5172)+1 种基金the Open Fund Project of the State Key Laboratory of Loess and Quaternary Geology (no.SKLLQG1611)the National Forestry Public Welfare Industry Scientific Research Project of China (no.201304309).
文摘Changes in annual radial growth is an important indication of climate change. Dendroclimatology studies in northern China have focused on linear statistical analysis,but lacking studies based on the process of ring formation to clarify the radial growth of trees. Tree-ring width standard chronology(STD) was established using samples of Larix principis-rupprechtii collected at 2303 m altitude on Luya Mountain. Using the Vaganov-Shashkin(VS) model to simulate growth and development, the internal physiological mechanism of radial growth is identified. It was concluded that:(1) the growing season of L. principis-rupprechtii was May to September;(2) soil moisture was a significant factor in the early and late growing seasons, and temperature was the dominant factor in its main growth period;and(3) formation of narrow ring widths was closely related to drought stress, the development of wide ring widths will be restricted by increasing future temperatures. The VS model is applicable for radial growth simulation of subalpine coniferous forests and for guiding the cultivation of local tree species in the future.
基金funded in large part by a grant(PNC 196-1011)from Forest and Wood Products Australia(FWPA)and funding and in-kind support from HVP,FSA and CSIRO
文摘Background: Stem radial growth in forests is not uniform. Rather, it is characterized by periods of relatively fast or slow growth, or sometimes no growth at all. These fluctuations are generally a function of varying environmental conditions(e.g. water availability) and, importantly, will also be associated with adjustments in proprties in the wood formed. Stand level conditions and forest management, particularly thinning and stand density will, thowever, also have a major influence on patterns of growth variation. We explore how different thinning histories and/or stand densities influence these dynamics of tree growth in the important commercial plantation species Pinus radiata D. Don.Methods: Daily stem size change was measured using electronic point dendrometers over two growing seasons on P. radiata trees at two sites, subjected to different thinning regimes. Timing, rates and periodicity of annual growth were calculated from these data.Results: Greater overall cross-sectional growth in thinned plots was driven mainly by two dynamics. First, the cessation of seasonal growth occurred at least 3 weeks later in the stands in which thinning had taken place. There was no difference between thinned/unthinned stands, however, in the timing of growth onset. Second, within the longer season, trees in thinned plots had more growth days(as much as 20% more) than unthinned plots. The rates of growth on days when growth occurred were not different, however. In this context, it is notable that in trees in the unthinned plots experiencing the most severe competition there were strong "pulses" of growth following drought-breaking rainfall events. Unthinned plots at high stand densities also maintained a smaller(but consistent) zone of dividing cells throughout the season than thinned plots.Conclusions: In Pinus radiata growing under conditions as in our study, conditions late in summer, particularly drought, have an important effect on the timing of cessation of growth. Early season temperature appears to have no effect in determining timing of annual growth. Limiting conditions during the season reduce growing duration, and thus total growth, more in unthinned stands than thinned stands. These findings are valuable in developing new generations of fine-scale growth and wood property models.
基金supported by the Strategic Leading Science and Technology Projects of Chinese Academy of Sciences (XDA05050201-04-01)the National Natural Science Foundation of China (41371053, 31500369)the ‘One Hundred Talent’ Program of Chinese Academy of Sciences (Y451H31001)
文摘Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential responses of plants to the changes in rainfall regimes, such as rainfall intensity and duration, and length of dry intervals. In this study, we investigated the effects of different rainfall patterns（e.g. small rainfall event with high frequency and large rainfall event with low frequency） on biomass, growth characteristics and vertical distribution of root biomass of annual plants in Horqin Sandy Land, Inner Mongolia of China during the growing season（from May to August） of 2014. Our results showed that the rainfall patterns, independent of total rainfall amount, exerted strong effects on biomass, characteristics of plant growth and vertical distribution of root biomass. Under a constant amount of total rainfall, the aboveground biomass（AGB）, belowground biomass（BGB）, plant cover, plant height, and plant individual and species number increased with an increase in rainfall intensity. Changes in rainfall patterns also altered the percentage contribution of species biomass to the total AGB, and the percentage of BGB at different soil layers to the total BGB. Consequently, our results indicated that increased rainfall intensity in future may increase biomass significantly, and also affect the growth characteristics of annual plants.
文摘The research on the characteristic frequency of precipitation is a great significance for guiding regional agricultural planning, water conservancy project designs, and drought and flood control. Droughts and floods occurred in northern Weihe Loess Plateau, affecting growing and yield of winter wheat in the area. Based on the daily precipitation data of 29 meteorological stations from 1981 to 2012, this study is to address the analysis of three different frequencies of annual precipitation at 5%, 50%, and 95%, and to determine the amount of rainfall excess and water shortage during seven growth stages of winter wheat at 5%, 10%, and 20% frequencies, respectively. Pearson type III curve was selected for this study to analyze the distribution frequency of annual rainfall and rainfall amount following seven growth stages of winter wheat crop in 29 stations of Northern Weihe loess plateau. As a result of our study, annual precipitation is gradually increasing from southwest to northeast of Northern Weihe loess plateau. The highest amount of annual precipitation occurred in the Baoji area and the lowest precipitation covered by the northwest area of Northern Weihe loess plateau. Moreover, the amount of rainfall of seven growth stages indicates that excessive rainfall occurs not only in the first stage (sowing to tillering) and seventh stage (flowering to ripening) but also in second stage (tillering to wintering). In the seventh stage, a large amount of excessive rainfall occurred in Changwu, Bin, Qianyang, Fengxiang, Baojiqu, and Baojixian. Moreover, water shortage is distributed in the third stage (from wintering to greening), the fourth stage (from greening to jointing), the fifth stage (from jointing to heading), and the sixth stage (from heading to flowering). Furthermore, the worst water shortages occurred in Hancheng, Heyang, Chengcheng, Pucheng, Dali, Tongchuan, and Fuping in the fourth stage (greening to jointing stage). Even though we study the crop water requirement under extreme rainfall conditions, the amount of rainwater still supply inadequate in some parts of the winter wheat growth stage. Therefore, this study provides main clues for the next step to study the irrigation water needs of winter wheat crops and to reduce agricultural risks in 29 counties in the northern loess plateau and other regions.
