Anatomical and morphological changes in Pinus sylvestris and Larix sibirica needles under impact of emissions from a large aluminum enterprise.

Species-specific anatomical and morphological characteristics of Pinus sylvestris and Larix sibirica needles were studied at different levels of tree stand pollution by aluminum smelter emissions. The anatomical characteristics of the needle were studied using light microscopy. The level of tree stand pollution was determined using the cluster analysis outcomes of the pollutant elements content (fluorine, sulfur, and heavy metals) in the needles. Four levels of tree stand pollution were separated: low, moderate, high, and critical, as well as background tree stand in unpolluted areas. It was found that the state of tree phytomass deteriorated with increasing levels of pollution (from low to critical): pine crown defoliation increased to 85%, and larch defoliation increased to 65%. The life span of pine needles was reduced to 2-3 years, with a background value of 6-7 years. The change of morphological parameters was more pronounced in P. sylvestris: the weight and length of the 2-year-old shoot decreased by 2.7-3.1 times compared to the background values; the weight of needles on the shoot and the number of needle pairs on the shoot-by 1.9-2.1 times. The length of the needle and shoot and the number of L. sibirica brachyblasts decreased by 1.8-1.9 times. The anatomical parameters of the needle also changed to a greater extent in P. sylvestris. Up to the high level of tree pollution, we observed a decrease in the cross-sectional area of the needle, central cylinder, vascular bundle, area and thickness of mesophyll, number and diameter of resin ducts by 18-66% compared to background values. At the critical pollution level, when the content of pollutant elements in pine needles reached maximum values, the anatomical parameters of the remaining few green needles were close to background values. In our opinion, this may be due to the activation of mechanisms aimed at maintaining the viability of trees. A reduction in thickness and area of assimilation tissue in the L. sibirica needle was detected only at the critical pollution level. An upward trend in these parameters was found at low, medium, and high pollution levels of tree stand, which may indicate an adaptive nature. The results suggested that at a similar pollution level of trees, the greatest amount of negative anatomical and morphological changes were recorded in pine needles, which indicates a greater sensitivity of this species to technogenic emissions.

Larches of Kuzhanovo Have a Unique Mutation in the atpF-atpH Intergenic Spacer.

The larches of Kuzhanovo (Larix sibirica Ledeb.) are protected trees with a round crown growing in the Southern Urals. In 2020 vandals sawed the sapwood of these trees, which exposed the problem of insufficient conservation measures. Their origin and genetic characteristics have been of particular interest to breeders and scientists. The larches of Kuzhanovo were screened for polymorphisms using SSR and ISSR analyses and the sequencing of genetic markers and genes GIGANTEA and mTERF, associated with wider crown shape. A unique mutation was discovered in the atpF-atpH intergenic spacer of all protected trees, but it was absent in some of their descendants and larches with similar crown shape. Mutations were discovered in the rpoC1 and mTERF genes of all samples. Flow cytometry did not reveal any changes in genome size. Our results suggest that the unique phenotype arose from point mutations in L. sibirica, but they are yet to be found in the nuclear genome. The concurrent mutations in the rpoC1 and mTERF genes may indicate that the round crown shape originates from the Southern Urals. The atpF-atpH and rpoC1 genetic markers are not common in studies of Larix sp., but their wider use could help to establish the origin of these endangered plants. The discovery of the unique atpF-atpH mutation also allows for stronger conservation and crime detection efforts.

Genetic Adaptation of Siberian Larch (Larix sibirica Ledeb.) to High Altitudes.

Forest trees growing in high altitude conditions offer a convenient model for studying adaptation processes. They are subject to a whole range of adverse factors that are likely to cause local adaptation and related genetic changes. Siberian larch (Larix sibirica Ledeb.), whose distribution covers different altitudes, makes it possible to directly compare lowland with highland populations. This paper presents for the first time the results of studying the genetic differentiation of Siberian larch populations, presumably associated with adaptation to the altitudinal gradient of climatic conditions, based on a joint analysis of altitude and six other bioclimatic variables, together with a large number of genetic markers, single nucleotide polymorphisms (SNPs), obtained from double digest restriction-site-associated DNA sequencing (ddRADseq). In total, 25,143 SNPs were genotyped in 231 trees. In addition, a dataset of 761 supposedly selectively neutral SNPs was assembled by selecting SNPs located outside coding regions in the Siberian larch genome and mapped to different contigs. The analysis using four different methods (PCAdapt, LFMM, BayeScEnv and RDA) revealed 550 outlier SNPs, including 207 SNPs whose variation was significantly correlated with the variation of some of environmental factors and presumably associated with local adaptation, including 67 SNPs that correlated with altitude based on either LFMM or BayeScEnv and 23 SNPs based on both of them. Twenty SNPs were found in the coding regions of genes, and 16 of them represented non-synonymous nucleotide substitutions. They are located in genes involved in the processes of macromolecular cell metabolism and organic biosynthesis associated with reproduction and development, as well as organismal response to stress. Among these 20 SNPs, nine were possibly associated with altitude, but only one of them was identified as associated with altitude by all four methods used in the study, a nonsynonymous SNP in scaffold_31130 in position 28092, a gene encoding a cell membrane protein with uncertain function. Among the studied populations, at least two main groups (clusters), the Altai populations and all others, were significantly genetically different according to the admixture analysis based on any of the three SNP datasets as follows: 761 supposedly selectively neutral SNPs, all 25,143 SNPs and 550 adaptive SNPs. In general, according to the AMOVA results, genetic differentiation between transects or regions or between population samples was relatively low, although statistically significant, based on 761 neutral SNPs (FST = 0.036) and all 25,143 SNPs (FST = 0.017). Meanwhile, the differentiation based on 550 adaptive SNPs was much higher (FST = 0.218). The data showed a relatively weak but highly significant linear correlation between genetic and geographic distances (r = 0.206, p = 0.001).

Activity of low-molecular weight components of Larix sibirica antioxidant system under exposure to technogenic pollution.

Changes in the antioxidant protection system of Larix sibirica Ledeb at different pollution levels caused by emissions from a large aluminum smelter (BrAS) have been studied. We revealed that the content of peroxide (H2O2) in the needles is a reliable marker of oxidative stress in the trees under pollution. The crucial role of non-enzymatic components, in particular, proline, phenolic compounds, ascorbic acid, glutathione, in reducing the level of free radicals in the needles cells was found. Proline concentration in the needles significantly rises with the increase in pollution levels from low to high. Under critical level pollution, it decreases by 40% compared to the background. The total content of ascorbic acid (ASC) in the needles of polluted trees varies slightly; however, there are significant changes in its various forms. With an increase in pollution to a high level, the content of the reduced form of ASC in the needles increases by 1.5-2.9 times compared to the background content. At a critical level of pollution, the total level of ascorbic acid and its reduced form falls, the content of the oxidized form reaches minimum values. The total content of phenolic compounds in the needles increased by 50-55%, concentration of flavonoids by 1.5-1.8 times, catechins by 1.9-2.5 times, proanthocyanidins by 45% compared to the background level under low, moderate, high pollution, whereas under critical pollution their content decreased. The absolute concentration of the reduced form glutathione in the needles falls by 1.9-3.0 times, the oxidized form increases by 1.5-2.0 times compared to the background. The ratio of reduced glutathione to oxidized glutathione decreased, especially during critical pollution. The data obtained show significant activation of Siberian larch biochemical protection at low, moderate and high levels of pollution by the aluminum smelter emissions. At a critical levels of contamination, a significant depletion of the pool of low-molecular antioxidants was observed.

Comparative Genomics of Seasonal Senescence in Forest Trees.

In the course of evolution, both flowering plants and some gymnosperms have developed such an adaptation to winter and unfavorable living conditions as deciduousness. Of particular interest is Siberian larch (Larix sibirica Ledeb.), which is the only species in the pine family (Pinaceae) with a seasonal deciduousness. New generation sequencing technologies make it possible to study this phenomenon at the genomic level and to reveal the genetic mechanisms of leaf and needle aging in angiosperms and gymnosperms. Using a comparative analysis of the genomes of evergreen and deciduous trees, it was found that the genes that control EXORDIUM LIKE 2 (EXL2) and DORMANCY-ASSOCIATED PROTEIN 1 (DRM1) proteins are most represented in Siberian larch, while an excess of genes that control proteins acting as immune receptors were found in evergreens. Orthologs from the family of genes that control leucine-rich repeat receptor-like kinases (LRR-RLK) contributed mostly to the distinction between evergreens and deciduous plants.

Modification of Arabinogalactan Isolated from Larix sibirica Ledeb. into Sulfated Derivatives with the Controlled Molecular Weights.

The process of sulfation of arabinogalactan-a natural polysaccharide from Larix sibirica Ledeb.-with sulfamic acid in 1,4-dioxane using different activators has been studied for the first time. The dynamics of the molecular weight of sulfated arabinogalactan upon variation in the temperature and time of sulfation of arabinogalactan with sulfamic acid in 1,4-dioxane has been investigated. It has been found that, as the sulfation time increases from 10 to 90 min, the molecular weights of the reaction products grow due to the introduction of sulfate groups without significant destruction of the initial polymer and sulfation products. Sulfation at 95 °C for 20 min yields the products with a higher molecular weight than in the case of sulfation at 85 °C, which is related to an increase in the sulfation rate; however, during the further process occurring under these conditions, sulfation is accompanied by the destruction and the molecular weight of the sulfated polymer decreases. The numerical optimization of arabinogalactan sulfation process has been performed. It has been shown that the optimal parameters for obtaining a product with a high sulfur content are a sulfamic acid amount of 20 mmol per 1 g of arabinogalactan, a process temperature of 85 °C, and a process time of 2.5 h.

Siberian larch (Larix sibirica Ledeb.) mitochondrial genome assembled using both short and long nucleotide sequence reads is currently the largest known mitogenome.

BACKGROUND: Plant mitochondrial genomes (mitogenomes) can be structurally complex while their size can vary from ~ 222 Kbp in Brassica napus to 11.3 Mbp in Silene conica. To date, in comparison with the number of plant species, only a few plant mitogenomes have been sequenced and released, particularly for conifers (the Pinaceae family). Conifers cover an ancient group of land plants that includes about 600 species, and which are of great ecological and economical value. Among them, Siberian larch (Larix sibirica Ledeb.) represents one of the keystone species in Siberian boreal forests. Yet, despite its importance for evolutionary and population studies, the mitogenome of Siberian larch has not yet been assembled and studied. RESULTS: Two sources of DNA sequences were used to search for mitochondrial DNA (mtDNA) sequences: mtDNA enriched samples and nucleotide reads generated in the de novo whole genome sequencing project, respectively. The assembly of the Siberian larch mitogenome contained nine contigs, with the shortest and the largest contigs being 24,767 bp and 4,008,762 bp, respectively. The total size of the genome was estimated at 11.7 Mbp. In total, 40 protein-coding, 34 tRNA, and 3 rRNA genes and numerous repetitive elements (REs) were annotated in this mitogenome. In total, 864 C-to-U RNA editing sites were found for 38 out of 40 protein-coding genes. The immense size of this genome, currently the largest reported, can be partly explained by variable numbers of mobile genetic elements, and introns, but unlikely by plasmid-related sequences. We found few plasmid-like insertions representing only 0.11% of the entire Siberian larch mitogenome. CONCLUSIONS: Our study showed that the size of the Siberian larch mitogenome is much larger than in other so far studied Gymnosperms, and in the same range as for the annual flowering plant Silene conica (11.3 Mbp). Similar to other species, the Siberian larch mitogenome contains relatively few genes, and despite its huge size, the repeated and low complexity regions cover only 14.46% of the mitogenome sequence.

Stepwise large genome assembly approach: a case of Siberian larch (Larix sibirica Ledeb).

BACKGROUND: De novo assembling of large genomes, such as in conifers (~ 12-30 Gbp), which also consist of ~ 80% of repetitive DNA, is a very complex and computationally intense endeavor. One of the main problems in assembling such genomes lays in computing limitations of nucleotide sequence assembly programs (DNA assemblers). As a rule, modern assemblers are usually designed to assemble genomes with a length not exceeding the length of the human genome (3.24 Gbp). Most assemblers cannot handle the amount of input sequence data required to provide sufficient coverage needed for a high-quality assembly. RESULTS: An original stepwise method of de novo assembly by parts (sets), which allows to bypass the limitations of modern assemblers associated with a huge amount of data being processed, is presented in this paper. The results of numerical assembling experiments conducted using the model plant Arabidopsis thaliana, Prunus persica (peach) and four most popular assemblers, ABySS, SOAPdenovo, SPAdes, and CLC Assembly Cell, showed the validity and effectiveness of the proposed stepwise assembling method. CONCLUSION: Using the new stepwise de novo assembling method presented in the paper, the genome of Siberian larch, Larix sibirica Ledeb. (12.34 Gbp) was completely assembled de novo by the CLC Assembly Cell assembler. It is the first genome assembly for larch species in addition to only five other conifer genomes sequenced and assembled for Picea abies, Picea glauca, Pinus taeda, Pinus lambertiana, and Pseudotsuga menziesii var. menziesii.

Siberian larch (Larix sibirica Ledeb.) chloroplast genome and development of polymorphic chloroplast markers.

BACKGROUND: The main objectives of this study were sequencing, assembling, and annotation of chloroplast genome of one of the main Siberian boreal forest tree conifer species Siberian larch (Larix sibirica Ledeb.) and detection of polymorphic genetic markers - microsatellite loci or simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs). RESULTS: We used the data of the whole genome sequencing of three Siberian larch trees from different regions - the Urals, Krasnoyarsk, and Khakassia, respectively. Sequence reads were obtained using the Illumina HiSeq2000 in the Laboratory of Forest Genomics at the Genome Research and Education Center of the Siberian Federal University. The assembling was done using the Bowtie2 mapping program and the SPAdes genomic assembler. The genome annotation was performed using the RAST service. We used the GMATo program for the SSRs search, and the Bowtie2 and UGENE programs for the SNPs detection. Length of the assembled chloroplast genome was 122,561 bp, which is similar to 122,474 bp in the closely related European larch (Larix decidua Mill.). As a result of annotation and comparison of the data with the existing data available only for three larch species - L. decidua, L. potaninii var. chinensis (complete genome 122,492 bp), and L. occidentalis (partial genome of 119,680 bp), we identified 110 genes, 34 of which represented tRNA, 4 rRNA, and 72 protein-coding genes. In total, 13 SNPs were detected; two of them were in the tRNA-Arg and Cell division protein FtsH genes, respectively. In addition, 23 SSR loci were identified. CONCLUSIONS: The complete chloroplast genome sequence was obtained for Siberian larch for the first time. The reference complete chloroplast genomes, such as one described here, would greatly help in the chloroplast resequencing and search for additional genetic markers using population samples. The results of this research will be useful for further phylogenetic and gene flow studies in conifers.

Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure.

Carbon pool densities and a first estimate of the total carbon pool in the Mongolian forest-steppe.

The boreal forest biome represents one of the most important terrestrial carbon stores, which gave reason to intensive research on carbon stock densities. However, such an analysis does not yet exist for the southernmost Eurosiberian boreal forests in Inner Asia. Most of these forests are located in the Mongolian forest-steppe, which is largely dominated by Larix sibirica. We quantified the carbon stock density and total carbon pool of Mongolia's boreal forests and adjacent grasslands and draw conclusions on possible future change. Mean aboveground carbon stock density in the interior of L. sibirica forests was 66 Mg C ha(-1) , which is in the upper range of values reported from boreal forests and probably due to the comparably long growing season. The density of soil organic carbon (SOC, 108 Mg C ha(-1) ) and total belowground carbon density (149 Mg C ha(-1) ) are at the lower end of the range known from boreal forests, which might be the result of higher soil temperatures and a thinner permafrost layer than in the central and northern boreal forest belt. Land use effects are especially relevant at forest edges, where mean carbon stock density was 188 Mg C ha(-1) , compared with 215 Mg C ha(-1) in the forest interior. Carbon stock density in grasslands was 144 Mg C ha(-1) . Analysis of satellite imagery of the highly fragmented forest area in the forest-steppe zone showed that Mongolia's total boreal forest area is currently 73 818 km(2) , and 22% of this area refers to forest edges (defined as the first 30 m from the edge). The total forest carbon pool of Mongolia was estimated at ~ 1.5-1.7 Pg C, a value which is likely to decrease in future with increasing deforestation and fire frequency, and global warming.

Treeline advances along the Urals mountain range - driven by improved winter conditions?

High-altitude treelines are temperature-limited vegetation boundaries, but little quantitative evidence exists about the impact of climate change on treelines in untouched areas of Russia. Here, we estimated how forest-tundra ecotones have changed during the last century along the Ural mountains. In the South, North, Sub-Polar, and Polar Urals, we compared 450 historical and recent photographs and determined the ages of 11,100 trees along 16 altitudinal gradients. In these four regions, boundaries of open and closed forests (crown covers above 20% and 40%) expanded upwards by 4 to 8 m in altitude per decade. Results strongly suggest that snow was an important driver for these forest advances: (i) Winter precipitation has increased substantially throughout the Urals (~7 mm decade(-1) ), which corresponds to almost a doubling in the Polar Urals, while summer temperatures have only changed slightly (~0.05°C decade(-1) ). (ii) There was a positive correlation between canopy cover, snow height and soil temperatures, suggesting that an increasing canopy cover promotes snow accumulation and, hence, a more favorable microclimate. (iii) Tree age analysis showed that forest expansion mainly began around the year 1900 on concave wind-sheltered slopes with thick snow covers, while it started in the 1950s and 1970s on slopes with shallower snow covers. (iv) During the 20th century, dominant growth forms of trees have changed from multistemmed trees, resulting from harsh winter conditions, to single-stemmed trees. While 87%, 31%, and 93% of stems appearing before 1950 were from multistemmed trees in the South, North and Polar Urals, more than 95% of the younger trees had a single stem. Currently, there is a high density of seedlings and saplings in the forest-tundra ecotone, indicating that forest expansion is ongoing and that alpine tundra vegetation will disappear from most mountains of the South and North Urals where treeline is already close to the highest peaks.

Temperature-induced responses of xylem structure of Larix sibirica (Pinaceae) from the Russian Altay.

PREMISE OF THE STUDY: Xylem structure determines the hydraulic and mechanical properties of a stem, and its plasticity is fundamental for maintaining tree performance under changing conditions. Unveiling the mechanism and the range of xylem adjustment is thus necessary to anticipate climate change impacts on vegetation. METHODS: To understand the mechanistic process and the functional impact of xylem responses to warming in a cold-limited environment, we investigated the relationship between temperature and tracheid anatomy along a 312-yr tree-ring chronology of Larix sibirica trees from the Altay Mountains in Russia. KEY RESULTS: Climate-growth analyses indicated that warming favors wider earlywood cell lumen, thicker latewood walls, denser maximum latewood, and wider rings. The temperature signal of the latewood was stronger (r > 0.7) and covered a longer and more stable period (from June to August) than that of earlywood and tree-ring width. Long-term analyses indicated a diverging trend between lumen and cell wall of early- and latewood. CONCLUSIONS: Xylem anatomy appears to respond to warming temperatures. A warmer early-growing season raises water conduction capacity by increasing the number and size of earlywood tracheids. The higher-performing earlywood tracheids promote more carbon fixation of the latewood cells by incrementing the rate of assimilation when summer conditions are favorable for growth. The diverging long-term variation of lumen and cell wall in earlywood vs. latewood suggests that xylem adjustments in latewood increase mechanical integrity and support increasing tree size under the ameliorated growing conditions.

VS-Cambium-Developer: A New Predictive Model of Cambium Functioning under the Influence of Environmental Factors.

Climate changes influence seasonal tree-ring formation. The result is a specific cell structure dependent on internal processes and external environmental factors. One way to investigate and analyze these relationships is to apply diverse simulation models of tree-ring growth. Here, we have proposed a new version of the VS-Cambium-Developer model (VS-CD model), which simulates the cambial activity process in conifers. The VS-CD model does not require the manual year-to-year calibration of parameters over a long-term cell production reconstruction or forecast. Instead, it estimates cell production and simulates the dynamics of radial cell development within the growing seasons. Thus, a new software based on R programming technology, able to efficiently adapt to the VS model online platform, has been developed. The model was tested on indirect observations of the cambium functioning in Larix sibirica trees from southern Siberia, namely on the measured annual cell production from 1963 to 2011. The VS-CD model proves to simulate cell production accurately. The results highlighted the efficiency of the presented model and contributed to filling the gap in the simulations of cambial activity, which is critical to predicting the potential impacts of changing environmental conditions on tree growth.

Actual prospects of using some types of larch growing in Kazakhstan in medicine.

Local plants can save natural resources and be used as a source of biologically active compounds, which can be high-quality, effective, and safe ingredients for pharmacological or chemical industries. Therefore, this study aimed to investigate the properties of two medicinal plants - the fine-scaled larch (Lárix Kaémpferi) and Siberian larch (Lárix Sibirica), which are growing in the Republic of Kazakhstan. We compared the two types of larches according to botanical affiliation and species description. We studied the alcoholic extracts from Lárix Kaémpferi and Lárix Sibirica to determine their physical and chemical properties. The data on the chemical composition of extractive compounds were generalized and systematized. The authenticity of Lárix Kaémpferi and Lárix Sibirica was established by external, anatomical, and diagnostic signs in microscopic examination and qualitative reactions. Specific indicators and their norms for raw materials were identified. This is the standard for both types of larch and determines their quality. We experimented with grinding fineness for studied materials and tested the impurities and moisture content of raw materials, total ash, and ash insoluble in a 10% hydrochloric acid solution. Determination of heavy metals and radionuclides was also considered. The quality specifications were developed based on the standardization of fine-scaled larch and Siberian larch.

The effect of aluminum smelter emissions on nutritional status of coniferous trees (Irkutsk Region, Russia).

Element contents in assimilation organs of trees are an essential component of a comprehensive forest condition diagnosis. They allow conclusions about the current nutritional status of trees and estimate the main risks for a sustainable forest ecosystem management in the future. The purpose of this research was to study the effect of highly aggressive fluorine-containing emissions from a large aluminum smelter on the nutritional status of coniferous trees Larix sibirica and Pinus sylvestris. Studies carried out in the background areas showed that the both species have the main part of the elements in optimal quantities. A deficiency is noted for potassium. The content of N, K, Mg, Na, S, F, Cu, Co, and Cd in L. sibirica needles was 1.2-5.2 times higher than in P. sylvestris needles. Under the influence of the aluminum smelter emissions, fluorine concentration in the tree needles increases by 13.8-30.0 times; sulfur by 2.9-3.6 times; heavy metals by 2.0-5.1 times; and nitrogen, calcium, magnesium, and sodium by 1.2-3.6 times, especially in the industrial zone and 5 km far from it. With the increasing distance from the smelter, the content of pollutants in the tree needles decreases. Values close to background are observed at a distance of over 40 km. According to index biogeochemical transformation, the elemental composition of P. sylvestris needles undergoes greater changes than L. sibirica ones under the influence emissions from the aluminum smelter. Changes in the element concentration of the tree needles caused by the impact of industrial emissions lead to a restructuring of the elements accumulation rows, as well as to a violation of the element quantitative ratios. Change of N:P:K, Ca:K, Ca:P, P:S, P:F, Mn:F, and Mn:Fe ratios points to serious nutrient imbalances in coniferous trees, which may reduce their vitality and growth in the long run.

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Based on the standard method of dendrochronology, we examined the tree-ring width index of two dominant tree species in the Altay Mountains, China, including Picea obovata and Larix sibirica. We analyzed the basal area increments (BAI) of those two species and the relationships between their radial growth and the climatic factors, which were compared in similar habitats. The results showed that the BAI of P. obovata was greater than L. sibirica, but the radial growth rate of L. sibirica was greater. In recent 60 years, the radial growth of P. obovata negatively correlated with high temperature in the fast growing stage of previous year, while the high temperature in June of current year promoted the radial growth of L. sibirica. There was a significantly negative correlation between radial growth of L. sibirica with temperature in January of current year. The sensitivity of tree growth to climate showed an obvious increase after an abrupt climate change under the background of recent warming and wetting trend in mid-1980s. Results of the moving correlation analysis showed that the response of the radial growth of P. obovata and L. sibirica to temperature and precipitation were enhanced under the background of climate change in the study area.