Growth–climate responses of high-elevation conifers in the central Hengduan Mountains,southwestern China

Improved understanding of tree-growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We applied dendroclimatological techniques to assess the effects of inter-annual climate variations on radial growth of high-elevation conifers in the central Hengduan Mountains, southwestern China. Eight tree-ring width chronologies of the major tree genera Abies and Picea that are aligned along an elevation gradient from 3200 to 4200 m a.s.l. were developed. Correlation and principal component analyses for the eight chronologies identified three groups of sites, representing different patterns of growth–climate relationships. Correlation and redundancy analyses with regional climate data revealed that radial growth of fir growing at high-elevation sites is enhanced by normal or warm summer temperatures (June and July) during the current growing season. In addition, radial growth of trees growing from high to middle elevations is sensitive to low temperatures during winter season. At low-elevation sites, trees display low sensitivity to temperature variation. However spring moisture availability becomes crucial for radial growth regardless of tree species. High- to middle-elevation conifers in the central Hengduan Mountains may benefit from the current climate warming, especially from rising winter temperatures.     

Growth responses of three coexisting conifer species to climate across wide geographic and climate ranges in Yukon and British Columbia

This work aimed to compare radial growth–climate relationships among three coexisting coniferous tree species across a wide geographic and climate range from southern British Columbia (BC) to central Yukon, Canada. Tree-ring data were collected from 20 mature stands of white spruce (Picea glauca), lodgepole pine (Pinus contorta var. latifolia), and subalpine fir (Abies lasiocarpa). Linear relationships between annual growth variation and monthly and seasonal climate were quantified with correlation and regression analyses, and variation in climate–growth responses over a climatic gradient were quantified by regressing growth responses against local mean climatic conditions. Temperatures had more consistent and stronger correlations with growth for all three species than precipitation, but growth–climate responses varied among species and among sites. In particular, pine and fir populations showed different responses between BC and Yukon, whereas spruce showed a more consistent response across the study domain. Results indicate that (1) the response and sensitivity of trees to seasonal climate variables vary among species and sites and (2) winter temperatures prior to growth may have significant impacts on pine and fir growth at some sites. The capacity to adapt to climate change will likely vary among the study species and across climatic gradients, which will have implications for the future management of mixed-species forests in Yukon and BC.     

Size-mediated climate-growth relationships in temperate forests: A multi-species analysis

In most dendrochronological studies, climate-growth relationships are established on dominant trees to minimize non-climatic signals. However, response to environmental factors may be affected by tree-size, which begs the question of the representativeness of dominant trees on the stand level. To highlight the variations in climate-growth relationships among sizes and species, under a wide range of ecological conditions (climate and soil properties), 61 pure even-aged stands were sampled across France. At each stand, two tree-ring chronologies were established from 10 big- to 10 small-diameter trees. Our objectives were, (1) to assess variations in climate sensitivity between the two size-diameter classes, and (2) to investigate the role of species and ecological conditions on these variations. The climate-growth relationships were evaluated from 122 tree-ring chronologies (1 220 trees) through extreme growth years and correlation function analyses. Sensitivity to climate of shade-intolerant and moderately shade-tolerant species (Picea abies (L.) Karst., Pinus sylvestris L. and Quercus petraea (Matt.) Liebl.) remained constant between the size-diameter classes for both temperature and hydric balance, while the shade-tolerant species Abies alba Mill. and Fagus sylvatica L. displayed significant differences, with larger trees being more sensitive to summer drought than smaller trees. This difference increased with increasing climatic xericity. Our results suggest that, for shade-tolerant species, (1) big trees could be more sensitive to climatic change especially under xeric climate, and (2) future tree ring studies should include trees stratified by size to produce unbiased estimation of sensitivity to climate.     

Tree-ring response of Larix chinensis on regional climate and sea-surface temperature variations in alpine timberline in the Qinling Mountains

Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.     

Effects of climatic conditions on tree-ring widths of three deciduous broad-leaved tree species at their northern distribution limit in Mont St. Hilaire,eastern Canada

This study examined the effects of climatic conditions on tree-ring widths of red oak (Quercus rubra), sugar maple (Acer saccharum) and American beech (Fagus grandifolia) at their northern distribution limit in Mont St. Hilaire, eastern Canada. A residual chronology of tree-ring width index was developed for each species. The tree-ring width of Q. rubra showed negative and positive correlations with May temperature and June precipitation in the current year, respectively. A. saccharum also showed similar patterns with Q. rubra, i.e., negative and positive correlations with June temperature and precipitation in the current year, respectively. F. grandifolia showed neither positive nor negative correlations with temperature and precipitation. The expressed population signals of tree-ring width chronologies of the three species indicated that climatic factors more greatly influenced the variations in tree-ring widths in the order Q. rubra > A. saccharum > F. grandifolia. Therefore, the radial growth of Q. rubra was most restricted by drought stress in early summer among the three species. Global warming is suggested to affect the radial growth of the three species differently by increasing drought stress at Mont St. Hilaire in eastern Canada.     

Climatic signal from <Emphasis Type="Italic">Pinus leucodermis</Emphasis> axial resin ducts: a tree-ring time series approach

Developing long-term chronologies of tree-ring anatomical features to evaluate climatic relationships within species might serve as an annual proxy to explore and elucidate the climatic drivers affecting xylem differentiation. Pinus leucodermis response to climate was examined by analyzing vertical xylem resin ducts in wood growing at high elevation in the Apennines of peninsular Southern Italy. Early- and latewood tree-ring resin duct chronologies, spanning the 1804–2010 time period, were constructed. We analyzed the relationships between resin duct chronologies and climate over the last century using correlation and response function analyses. Overall, results showed that ring width and resin duct relationships differed between early- and latewood, which indicated conditions affecting growth were not associated with resin duct production. Results also revealed differential responses to climate between early- and latewood resin duct chronologies. A notable observation was a positive and stable relationship between latewood resin duct number chronology and July maximum temperature throughout the twentieth century. This result suggested resin ducts might be a suitable proxy to evaluate P. leucodermis response to climate in the study area.     

Comparison of growth response ofAbies andPicea species to climate in Mt. Norikura, Central Japan

Tree-ring chronologies were developed fromAbies mariesii Masters andPicea jezoensis ssp.hondoensis (Mayr) P. Schmidt collected at different altitudes of Mt. Norikura, central Japan. The tree-ring parameters of ring width and maximum density were measured by soft X-ray densitometry. The measurement series were detrended by fitting a 33-year cubic smoothing spline and autoregressive model. The correlation between species and between sites showed different responses of the species to climate in terms of ring width and maximum density. The correlation coefficient between sites within a species was higher than that between species for a site in the ring width, and the coefficient between species for a site was higher in maximum density. The correlation coefficient between tree-ring chronology and monthly climate data set showed different responses of radial growth to climate. The different response was probably explained by the difference in the length of the growing season. High summer temperature increased the maximum density of the two species and the radial growth inAbies mariesii. Summer precipitation correlated negatively to maximum density, but it did not affect the ring width of either species. The climatic signals could be extracted from ring-width and maximum-density chronologies of both species.     

Using a spatiotemporal climate model to assess population-level Douglas-fir growth sensitivity to climate change across large climatic gradients in British Columbia, Canada

Effective adaptation of forest management practices to climate change will require a good understanding of the ecological and climatic factors influencing tree sensitivities and responses to climate. Using tree-ring data collected from 33 stands of mature interior Douglas-fir (Pseudotsuga menziesii var. glauca) spanning a wide climatic range in British Columbia (BC), Canada, we present an approach combining high-resolution spatiotemporal climate data with traditional dendroecological analyses to quantify relationships between population climate-growth sensitivity and provenance (i.e., seed-source origin) climate. Key results showed that Douglas-fir climate-growth sensitivities were strongly linked to provenance climate and varied in coherent patterns across climatic gradients. Climate-growth sensitivities and responses were sometimes opposite between provenances from disparate climates. Perhaps most importantly, our results showed that Douglas-fir productivity across most of its range was sensitive to moisture limitations, and this sensitivity increased strongly with decreasing provenance mean annual precipitation and increasing heat-moisture index. Using geographic information systems, we visualize the link between provenance mean annual precipitation and climatic sensitivity of Douglas-fir across BC to identify “high risk” populations. By understanding the link between biological responses and climate, forest managers may be able to spatially identify sensitive populations using spatiotemporal climate data.     

Dendroclimatological regions of Douglas fir (<Emphasis Type="Italic">Pseudotsuga menziesii</Emphasis> Franco) in western Poland

Abstract Six Douglas fir (Pseudotsuga menziesii Franco) stands were selected in both the Sudety Mountains and the Great Poland Lowland. These two regions are distinctly different with regard to thermal and pluvial conditions. In each stand, two increment cores per tree were extracted from 20 approximately 100-year-old trees and the tree-ring widths measured. It is clear from the different growth reactions of the study trees to the climatic conditions that the Sudety Mountains and the Great Poland Lowland are two dendrochronologically separate regions. The tree-ring width chronologies form homogeneous groups for each region. The tree ring–climate models for Douglas fir in both regions indicate similarities and differences. The similarities among chronologies are attributed to winter temperature. The differences are attributed to rainfall (which changes with longitude and altitude of sites) during the vegetation season.     

Larix olgensis growth-climate response between lower and upper elevation limits:an intensive study along the eastern slope of the Changbai Mountains,northeastern China

Larix olgensis is a dominant tree species in the forest ecosystems of the Changbai Mountains of northeast China.To assess the growth response of this species to global climate change,we developed three tree-ring width and biomass chronologies across a range of elevations in the subalpine forests on the eastern slope of the Changbai Mountains.We used dendroclimatic analyses to study key factors limiting radial growth in L.olgensis and its variation with elevation.The statistical characteristics of chronologies suggested that elevation is a determinant of tree growth patterns in the study area.Response function analysis of chronologies with climate factors indicated that climate–growth relationships changed with increasing elevation:tree growth at high elevation was strongly limited by June temperatures of the previous year,and as elevation decreases,the importance of temperature decreased;tree radial growth at mid-elevation was mainly controlled by precipitation towards the end of the growing season of the current year.Biomass chronologies reflected a stronger climatic signal than tree-ring width chronologies.Spatial correlation with gridded climate data revealed that our chronologies contained a strong regional temperature signal for northeast China.Trees growing below timberline appeared to be more sensitive to climate,thus optimal sites for examining growth trends as a function of climate variation are considered to be just below timberline.Our study objective was to provide information for more accurate prediction of the growth response of L.olgensis to future climate change on the eastern slope of the Changbai Mountains,and to provide information for future climate reconstructions using this tree species in humid and semi humid regions.     

Growth response of Pinus pinaster Ait. to climatic variables in central Spanish forests

? The effect of climatic variables (temperature and precipitation) on radial growth of the Mediterranean Maritime pine (Pinus pinaster Ait.) was studied using dendrochronological techniques in the Iberian Peninsula.

? Ten tree-ring width chronologies, along the central distribution area of the species, were built. Chronology variability was analysed using Principal Component Analysis (PCA) for the period 1952–2005.

? The first principal component (PC1) explained 56% of tree-growth variability. Tree-growth association with climate was analysed at regional and local scales using correlation coefficient and bootstrapped response functions.

? Radial growth at both scales was positively correlated with rainfall during and prior to the growing season at all sites, and with summer rainfall before the growing season at five sites. Mean temperature effect changed according to the sampling site, from non-significant at the highest sites to significant (positive relationship in winter) at the lowest sites. Growth season temperature also had a negative effect.

? The Kalman filter was applied to estimate changing association between growth and climate over-time. Results suggested a change in association, initiated in the 80s, from non-significant to significant (*p < 0.05) at six of the sampling sites.

? Pinus pinaster is an accurate species for analysing tree-growth association with climate and for studying plant behaviour under global change conditions.

     

Growth response to climate and drought change along an aridity gradient in the southernmost Pinus nigra relict forests

Context

Tree populations at the rear edge of species distribution are sensitive to climate stress and drought. However, growth responses of these tree populations to those stressors may vary along climatic gradients.

Aims

To analyze growth responses to climate and drought using dendrochronology in rear-edge Pinus nigra populations located along an aridity gradient.

Methods

Tree-ring width chronologies were built for the twentieth century and related to monthly climatic variables, a drought index (Standardized Precipitation–Evapotranspiration Index), and two atmospheric circulation patterns (North Atlantic and Western Mediterranean Oscillations).

Results

Growth was enhanced by wet and cold previous autumns and warm late winters before tree-ring formation. The influence of the previous year conditions on growth increased during the past century. Growth was significantly related to North Atlantic and Western Mediterranean Oscillations in two out of five sites. The strongest responses of growth to the drought index were observed in the most xeric sites.

Conclusion

Dry conditions before tree-ring formation constrain growth in rear-edge P. nigra populations. The comparisons of climate-growth responses along aridity gradients allow characterizing the sensitivity of relict stands to climate warming.     

暖温带幼林树轮宽度气候变化响应分析--以山东蒙山黑松树轮气候研究为例

根据采自山东蒙山地区两组幼龄黑松树木年轮样本,研制出单点和区域树轮宽度年表,分析了蒙山黑松树轮宽度年表的统计参数和径向生长的气候限制因子,并尝试重建相关密切的气候因子,探讨蒙山黑松径向生长与大范围气候变化的关联。研究结果表明,（1）蒙山黑松树轮宽度年表的统计参数都比较高,说明蒙山黑松树轮宽窄变化包含有较多的气候环境变化信息。（2）蒙山黑松径向生长变化与当年4-9月降水量呈显著正相关。同时,当年5-7月异常高温也对蒙山黑松径向生长变化产生显著抑制。通过黑松树轮宽度年表对4-9月降水量的模拟重建结果表明蒙山黑松具有较大树轮气候研究潜力。（3）蒙山黑松树轮宽度生长与太平洋大范围气候波动存在显著关联。     

Climatic responses of tree-ring widths of <Emphasis Type="Italic">Larix gmelinii</Emphasis> on contrasting north-facing and south-facing slopes in central Siberia

An analysis was performed on the climatic responses of the radial growth of Larix gmelinii (Rupr.) Rupr. on contrasting north-facing and south-facing slopes in Tura, central Siberia. We developed chronologies of tree-ring width for four plots, designated as north-upper, northlower, south-upper, and south-lower. Both residual and standard chronologies of tree-ring widths exhibited a significant positive correlation with temperature from the end of May until early June in all four plots. The chronologies of ring width did not reveal any major difference in the response to temperature among the four plots. The standard chronologies of ring widths on the north-facing slope were negatively correlated with precipitation during the winter (October–April) and in early and mid-May, whereas the residual chronologies did not reveal clear relationships with precipitation during the winter and May. The significant correlation between ring width and temperature from the end of May until early June indicates that temperatures in springtime play a significant role in the radial growth of L. gmelinii. The negative correlations between standard chronologies of tree-ring width and precipitation in the winter and in May on the north-facing slope indicate that lowfrequency fluctuations in snowfall have negative effects on the radial growth. However, these effects vary and depend on the microscale topography. Part of this report was presented at the 55th Annual Meeting of the Japan Wood Society, March 2005, Kyoto     

Patterns of spread of Pinus contorta Dougl. ex Loud. invasion in a Natural Reserve in southern South America

Pinus species, which have formed the foundation of commercial forestry industry in many countries, are known to be invasive in natural ecosystems, especially in the Southern Hemisphere. Pinus contorta is considered one of the most aggressively invasive plantation species. In this paper we aim to: (a) determine patterns of P. contorta invasion in relation to its size and age structure and spatial distribution and (b) determine the effect of vegetation cover on its regeneration. For this purpose, we have chosen the Malalcahuello National Reserve in south-central Chile, which is dominated by Araucaria araucana forests. In the three P. contorta trial plots, attributes were measured in order to describe its current structure. We selected one of the three P. contorta trial plots and set eight 50 m wide and 125 m centrifugal transects starting at the North Azimuth (0°) orientation and then one each 45°. In each transect 25 circular plots of 2.5 m radius were established every 25 m. In each plot, we measured collar diameter (CD) for each P. contorta individual and adjusted a diameter–age function. We recorded the presence of cones for each individual P. contorta within the plots and the total number of P. contorta individuals. In each plot, we measured percent vegetation cover (grass, understory and canopy). The selected parent stand showed a decrease in density from the original plantation spacing, from 2500 to 150 plants ha⁻¹. Of all sampled individuals, only a 38% had cones. We found reproductive structures in trees as young as 5-year-old. Regeneration was found in all transects. Mean density for the area was 1600 plants ha⁻¹, and the greater plant number was found in the West transect, reaching an average of 6600 plants ha⁻¹. Through the interpolation performed with the kriging method, a map of the area with the spatial gradient of plant density was obtained. Naturally regenerated individuals of P. contorta occupied an area of 78 ha where the most distant individual is located in the southeast direction at an average distance of 1200 m from the three study plots. We determined that a positive association exists between P. contorta and the species A. araucana and Nothofagus antarctica. The capacity for early and consistent reproduction and the establishment of individuals dispersed at great distances from the original plots allow us to conclude that P. contorta has great potential as an invasive species in forests of this area of the Andes of southern South America. Invasion of P. contorta has many important implications for the conservation of native forests in our region including diminished regeneration of A. araucana.     

Twentieth-century decline of large-diameter trees in Yosemite National Park,California, USA

Studies of forest change in western North America often focus on increased densities of small-diameter trees rather than on changes in the large tree component. Large trees generally have lower rates of mortality than small trees and are more resilient to climate change, but these assumptions have rarely been examined in long-term studies. We combined data from 655 historical (1932–1936) and 210 modern (1988–1999) vegetation plots to examine changes in density of large-diameter trees in Yosemite National Park (3027 km²). We tested the assumption of stability for large-diameter trees, as both individual species and communities of large-diameter trees. Between the 1930s and 1990s, large-diameter tree density in Yosemite declined 24%. Although the decrease was apparent in all forest types, declines were greatest in subalpine and upper montane forests (57.0% of park area), and least in lower montane forests (15.3% of park area). Large-diameter tree densities of 11 species declined while only 3 species increased. Four general patterns emerged: (1) Pinus albicaulis, Quercus chrysolepis, and Quercus kelloggii had increases in density of large-diameter trees occur throughout their ranges; (2) Pinus jeffreyi, Pinus lambertiana, and Pinus ponderosa, had disproportionately larger decreases in large-diameter tree densities in lower-elevation portions of their ranges; (3) Abies concolor and Pinus contorta, had approximately uniform decreases in large-diameter trees throughout their elevational ranges; and (4) Abies magnifica, Calocedrus decurrens, Juniperus occidentalis, Pinus monticola, Pseudotsuga menziesii, and Tsuga mertensiana displayed little or no change in large-diameter tree densities. In Pinus ponderosa–Calocedrus decurrens forests, modern large-diameter tree densities were equivalent whether or not plots had burned since 1936. However, in unburned plots, the large-diameter trees were predominantly A. concolor, C. decurrens, and Q. chrysolepis, whereas P. ponderosa dominated the large-diameter component of burned plots. Densities of large-diameter P. ponderosa were 8.1 trees ha⁻¹ in plots that had experienced fire, but only 0.5 trees ha⁻¹ in plots that remained unburned.     

Influence of drought on tree rings and tracheid features of Pinus nigra and Pinus sylvestris in a mesic Mediterranean forest

We investigated the influence of climate on the ring width and xylem anatomy of two co-occurring pines (Pinus nigra Arn. and P. sylvestris L.) in the mountains of east-central Spain in order to test their utility for dendroclimatic reconstructions. We developed chronologies of ring width, mean lumen diameter and mean cell-wall thickness (in the earlywood, latewood, and the total annual ring) and the number of cells between 1960 and 2006. Drought, expressed as the standardized precipitation-evapotranspiration index (SPEI), was the main climatic driver of tree radial growth, although trees were also sensitive to temperature (negative effect in previous autumn and current summer) and precipitation (with a general positive effect). P. sylvestris response was stronger to climate of the current year, whereas the effect of previous-year climate was more important for P. nigra. Warm and dry summers reduced ring width, tracheid lumen, and wall thickness in both species, whereas warm winter-spring temperatures had the opposite effect, primarily for P. sylvestris. Previous-year or early-season conditions mainly affected earlywood features, whereas latewood was more responsive to summer climate. Overall, climate appeared to be a stronger limiting factor for P. sylvestris. During periods of drought, cell-wall thickness was reduced while lumen width increased in the latewood of P. sylvestris. This could compromise its hydraulic safety against drought-induced cavitation as our site was close to the southern and dry edge of the species distribution area. Our results suggest that anatomical variables record different and stronger climate information than ring width variables, especially in P. sylvestris. Reconstruction models for SPEI at the 3-month scale were developed for July–August and September–October using principal components regression. The best models included anatomical and width variables of both pine species suggesting that tracheid chronologies can be useful for drought reconstructions especially at mesic sites or with species that encode a mixed drought and temperature-precipitation signal.     

Geographically structured and temporally unstable growth responses of Juniperus thurifera to recent climate variability in the Iberian Peninsula

Geographically structured tree-ring networks are needed to fully understand the spatiotemporal variability in climatic sensitiveness of trees and to study their future responses to global warming. We aim to identify the spatially constrained structure of radial-growth patterns of the Spanish juniper (Juniperus thurifera L.) and to assess whether their climate–growth responses were unstable during the late twentieth century. Tree–ring width chronologies were built for 13?J. thurifera stands in Spain using dendrochronological methods and related to monthly climatic data. Sites were grouped according to their growth patterns using hierarchical cluster analysis. The relationships among geographical, climatic and stand features and their influence on radial growth were evaluated using redundancy analysis. The climate–growth relationships and their temporal stability were assessed using Pearson’s and moving bootstrapped correlations, respectively. Stands formed three geographical groups according to their high-frequency growth variation: North West and Centre, North East and South East. We found that J. thurifera radial-growth patterns depended on geographical and climatic factors, but not on the stand structure, and responded to a northwest–southeast gradient of decreasing rainfall and influence of Atlantic Westerlies and Mediterranean cyclonic activity. The positive response to June precipitation was unstable during the late twentieth century and started earlier in populations from western mesic sites than in eastern xeric sites. This pattern may be related to either decreasing water availability in western than in eastern sites or the resilience of J. thurifera growth from xeric sites in response to the increasing summer aridity.     

Climatic response of ring width and maximum latewood density of Larix sibirica in the Altay Mountains, reveals recent warming trends

? Introduction

Siberian larch (Larix sibirica) is a highly climate sensitive species. Presently, the Altay Mountains is covered by widespread forests dominated by Siberian larch and thus has a great potential for dendroclimatological studies. However, tree-ring network of the Altay Mountains has not yet been well developed. The development of the new chronologies and the knowledge about the influence of climatic variables on tree growth is needed.

? Method

X-ray densitometric techniques were applied to obtain ring width (RW) and maximum latewood density (MXD) of Siberian larch from two upper tree line sites in the Altay Mountains, China. Climatic responses in ring widths and maximum latewood densities from the Altay Mountains (China, Russia, and Mongolia) were investigated by simple correlation analyses. To assess the common growth forces among the individual sites of the Altay Mountains, simple correlation, principal component analyses, and spatial correlation analysis were applied over the common period of the chronologies.

? Results

Ring width and maximum latewood density increases with decreasing precipitation, increasing temperature from late spring to late summer during the growing season. Based on the results of principal component analyses and spatial correlation analysis, summer temperature (June?CJuly) is the most important forces on the Siberian larch growth of the Altay Mountains. The growth of Siberian larch in the Altay Mountains captures the current warming trend. The growth of Siberian larch did not clearly lose its sensitivity under most recent warming in our study areas.

? Conclusions

The new MXD chronologies is presently the longest, absolutely dated, tree-ring density record yet developed from China. The climate response analysis shows that the RW and MXD of Siberian larch have strong responses to temperature in the growing season. Thus, MXD and RW of Siberian larch provides the best information for climate reconstruction in the warm season. Tree-rings of Siberian larch allow detecting the recently observed warming trend and putting it into the long-term climatic context in the Altay Mountains, due to the strong growth sensitivity to temperature change.     

帽儿山地区不同种源樟子松树轮对气候因子的响应

[目的]为了进一步了解不同种源的樟子松在帽儿山地区的生长差异,研究该地区气候因子对樟子松径向生长的影响,本文建立了来自于阿尔山、高峰、红花尔基、卡伦山、图强罕达盖和金山等7个种源樟子松树轮年表。[方法]通过年轮-气候响应分析、相关分析、主成分分析,探讨了不同种源樟子松径向生长与气候因子的响应差异。[结果]表明:7个种源地樟子松树轮年表整体变化趋势基本相似,但局部也有不同之处,除图强种源外,其余6个种源地樟子松在生长初期年轮宽度呈增加趋势。阿尔山、高峰、红花尔基和卡伦山种源地樟子松径向生长与当年2月平均温度显著正相关,罕达盖种源地樟子松径向生长与前一年4月平均温度显著正相关;高峰、图强、卡伦山种源地樟子松径向生长与当年6月降水显著正相关,阿尔山、高峰、金山、卡伦山、红花尓基、图强种源樟子松的径向生长主要与前一年8月降水显著负相关。[结论]多数种源的樟子松在初期径增长较快,与当年2月份的温度和6月份的降水量有正相关的响应性,而与前一年8月份的降水量有负相关的响应性。