Effects of phyllotaxy on variation and inner relationships of leaflet traits in compound-leaved plants.

To understand the distribution pattern of leaflet traits in compound-leaved along with phyllotaxy, we selected three compound-leaved trees with opposite phyllotaxy in Xiaoxing' an Mountains, Fraxinus mandshurica, Phellodendron amurense, Juglans mandshurica, as the research objects. We measured leaf thickness, leaf area, specific leaf area, leaf dry matter content, palisade tissue thickness, spongy tissue thickness, ratio of palisade tissue thickness to spongy tissue thickness, and carbon content, nitrogen content, phosphorus content of leaflets at different phyllotaxy positions. We analyzed the variation of leaflet traits with phyllotaxy and the influence of phyllotaxy on the inner relationships between leaflet traits. The results showed that the variation of leaflet area, leaflet dry matter content, spongy tissue thickness and ratio of palisade tissue thickness to spongy tissue thickness with the increase of phyllotaxy were mainly divided into three types: increase, decrease, first increase and then decrease. Leaflet thickness, specific leaflet area, palisade tissue thickness, as well as nutrient contents did not change with phyllotaxy. Within compound leaves of three species, the variation coefficients and plasticity index of leaflet thickness, leaflet area, specific leaflet area, leaflet dry matter content, palisade tissue thickness, spongy tissue thickness, ratio of palisade tissue thickness to spongy tissue thickness ranged from 6.1% to 28.6% and from 0.14 to 0.70, respectively. Phyllotaxy had a significant effect on the bivariate correlation between leaflet traits. Specific leaflet area and leaflet dry natter content were negatively correlated in different phyllotaxy positions of F. mandshurica and J. mandshurica. Leaflet nitrogen content and phosphorus content showed a positive correlation in different phyllotaxy positions of F. mandshurica and P. amurense. The first and secondary leaflets (the first leaflets farthest from the base of the petiole) of J. mandshurica showed a conservative strategy, while the seventh and eighth leaflets showed an acquisition strategy. Leaflets of F. mandshurica and P. amurense did not show different ecological strategies.

Soil water content and nitrogen differentially correlate with multidimensional leaf traits of two temperate broadleaf species.

The variation and correlation of leaf economics and vein traits are crucial for predicting plant ecological strategies under different environmental changes. However, correlations between these two suites of traits and abiotic factors such as soil water and nitrogen content remain ambiguous. We measured leaf economics and vein traits as well as soil water and nitrogen content for two different shade-tolerant species (Betula platyphylla and Acer mono) in four mixed broadleaved-Korean pine (Pinus koraiensis) forests along a latitudinal gradient in Northeast China. We found that leaf economics traits and vein traits were decoupled in shade-intolerant species, Betula platphylla, but significantly coupled in a shade-tolerant species, A. mono. We found stronger correlations among leaf traits in the shade tolerant species than in the shade intolerant species. Furthermore, leaf economic traits were positively correlated with the soil water gradient for both species, whereas vein traits were positively correlated with soil water gradient for the shade intolerant species but negatively correlated in the shade tolerant species. Although economic traits were positively correlated with soil nitrogen gradient in shade intolerant species but not correlated in shade tolerant species, vein traits were negatively correlated with soil nitrogen gradient in shade tolerant species but not correlated in shade intolerant species. Our study provides evidence for distinct correlations between leaf economics and vein traits and local abiotic factors of species differing in light demands. We recommend that the ecological significance of shade tolerance be considered for species when evaluating ecosystem functions and predicting plant responses to environmental changes.

[Response of Soil Enzyme Activity and Chemical Properties to Nitrogen Addition in a Korean Pine Plantation].

Soil enzymes participate in numerous complex biochemical processes that take place in the soil and play an important role in the material circulation of terrestrial ecosystems. To explore the response of soil enzyme activities and chemical properties to nitrogen deposition in temperate forests, this study analyzed four soil enzyme activities based on the nitrogen addition experiment plot of Korean pine (Pinus koraiensis) plantation, which was located in the Liangshui National Natural Reserve, Heilongjiang Province. The results showed that the activities of N-acetyl-glucosidase (NAG) and alkaline phosphatase (AKP) increased significantly with increasing nitrogen application concentration. The activity of beta-glucosidase (BG) and acid phosphatase (ACP) was not significantly different among different nitrogen application treatments. The contents of total carbon, total nitrogen, total phosphorus, and available nitrogen and four enzyme activity in the upper soil (0-10 cm) under the same nitrogen application level were significantly higher than those in the lower soil (10-20 cm), but the pH values were not significantly different. Total carbon has an extremely significant positive correlation with NAG, BG, AKP, and ACP. Total nitrogen has an obvious or extremely significant positive correlation with BG, NAG, and AKP as well as ACP. The available nitrogen has an obvious and highly significant positive correlation with NAG and AKP. The total phosphorus has an obvious and extremely significant positive correlation with ACP and AKP, respectively. The nitrogen application level and the soil layer had different effects on soil enzyme activity and soil chemical properties. Long-term large input of nitrogen can directly or indirectly change soil chemical properties and affect soil enzyme activity.

[Effects of species diversity and phylogenetic diversity on productivity of a mixed broadleaved-Korean pine forest.] / ç‰©ç§å¤šæ ·æ€§å’Œç³»ç»Ÿå‘è‚²å¤šæ ·æ€§å¯¹é˜”å¶çº¢æ¾æž—ç”Ÿäº§åŠ›çš„å½±å“.

The relationship between biodiversity and ecosystem function is one of the hot spot in ecological research. The driving effect of plant diversity on forest productivity has been widely focused, but its underlying mechanisms are still controversial. We explored the impacts of species diversity and phylogenetic diversity on forest productivity at different spatial scales based on a 9 hm2 forest dynamic monitoring plot of typical mixed broadleaved-Korean pine (Pinus koraiensis) forest in Liangshui National Nature Reserve, Heilongjiang Province, with the censuses data in 2005 and 2015, using linear regression and structural equation models. The results showed that species diversity and phylogenetic diversity were both positively correlated with productivity. The strength of species diversity on productivity gradually enhanced as spatial scales increased, while the effects of phylogenetic diversity on productivity showed opposite trend. On small scales, the effects of phylogenetic diversity on productivity was stronger than species diversity. Moreover, productivity was affected by abiotic factors. Soil factors were significantly positively correlated with productivity at different scales, which was gradually dominated as spatial scales increased. Our results indicated that evolutionary information should be considered in future ecosystem function studies, which might provide additional explanatory power for other diversity metrics. Meanwhile, the effects of spatial scales and abiotic factors should also be considered, which could provide a scientific basis for further understanding the mechanisms underlying the changes of forest productivity.

[Variation of morphological and anatomical traits of fine roots of three plant species in Xiao-xing'an Mountains, China]. / å°å ´å®‰å²­3ç§æ¤ç‰©ç»†æ ¹å½¢æ€å’Œè§£å‰–æ€§çŠ¶çš„å˜å¼‚.

We measured the morphological and anatomical traits of fine roots with 1-5 order in needleleaf species of Pinus koraiensis, broadleaf species of Acer mono, and shrub of Corylus mandshurica, with the aim to understand trait variations among root orders and species. The results showed that there was no significant difference in root diameter and root length among the three species, but was significant inter-specific differences in other traits. The stele diameter (117.91-2392.05 µm) and stele to diameter ratio (0.31-1.87) of P. koraiensis were significantly greater than that of A. mono and C. mandshurica, whereas tissue density of A. mono was significantly higher than that of P. koraiensis and C. mandshurica. Root diameter, root length, tissue density, stele diameter and stele to diameter ratio all increased with root order, but specific root length decreased for the three species. For all the species, there was a significant correlation between morphological and anatomical traits, such as root diameter and stele diameter, but the regression slope was significantly different between the absorption root (1-3 order) and the transport root (4-5 order). Root diameter was significantly positively correlated with stele diameter and cortical thickness of the three species, with the regression slope being significantly different among species.

[Vertical variation and model construction of area and dry mass for a single leaf from six broadleaved trees in mixed broadleaved-Korean pine forests.] / 阔叶红松林6ç§é˜”å¶æ ‘å•ä¸ªå¶ç‰‡å¶é¢ç§¯å’Œå¶å¹²è´¨é‡çš„åž‚ç›´å˜å¼‚åŠæ¨¡åž‹æž„å»º.

Rapidly and accurately predicting leaf area (LA) and leaf dry mass (LDM) are essential for exploring the response of plant traits to climate change. Empirical models suitable for predicting LA and LDM of a single leaf for various broadleaved tree species at the regional scale have not been proposed. We selected six broadleaved tree species in four mixed broadleaved-Korean pine (Pinus koraiensis) forests in northeastern China, including Betula platyphylla, Tilia amurensis, Populus davidiana, Betula costata, Fraxinus mandshurica and Ulmus laciniata, and measured leaf length, leaf width, leaf thickness, LA and LDM at different canopy layers (top, middle, and low). Using the median of leaf length and width ratio as the classification criterion, the six species were sorted into two groups. We tested whether different canopy layers for each group of broadleaved tree species had significant impacts on the empirical model for predicting LA and LDM. We constructed empirical models suitable for predicting LA and LDM of a single leaf at different canopy layers at the regional scale, and verified their forecast accuracy, and further evaluated their applicability for predicting LA and LDM of same broadleaved tree species in other regions. These results showed that the LA of a single leaf increased significantly with the decreases of canopy height for the six tree species, while the LDM of some broadleaved tree species showed a downward trend. The canopy height had significant impacts on constructing the empirical model for LA and LDM. The average forecast accuracy of empirical model was 95% and 83% for LA and LDM of a single leaf across canopy layers for two groups of broadleaved tree species, respectively. The average forecast accuracy was 94% and 80% for predicting LA and LDM of corresponding broadleaved tree species in other regions, respectively, indicating that the empirical models constructed in this study had a universal applicability in Northeast China.

Influence of automatic exposure on the estimation of seasonal variations in leaf area index measured by digital hemispherical photograph.

Automatic exposure is one of the important error sources during measurement of leaf area index (LAI) by digital hemispherical photography (DHP). This study was conducted in a mixed broadleaved-Korean pine (Pinus koraiensis) forest, a secondary birch (Betula platyphylla) forest, a Korean pine plantation and a Dahurian larch (Larix gmelinii) plantation in the Xiaoxing'an Mountains. LAI was measured using DHP and LAI-2200 plant canopy analyzer in the middle of June to September. We compared LAI values measured through these two methods, and then tested whether the forest type and study period had a significant influence on the correlations between the measured values of those two methods. We constructed empirical models for correcting the errors caused by automatic exposure for LAI values measured through DHP at different study periods in different forest types. The results showed that LAI from DHP was underestimated by 20%-49% rela-tive to that from LAI-2200 in four study periods of the four forest types. Forest type had no significant effect on the construction of empirical models between these two measuring methods of LAI, whereas study period showed significant effects. Two classified empirical models (A and B) were constructed, which were suitable for correcting the LAI from DHP in June and September, July and August in four forest types, respectively. After being corrected by the classified empirical models, LAI from DHP of the four forest types increased by 45%-79%, and the measurement accuracy could be improved to 83%-94%. Classified empirical models between LAI from DHP and LAI-2200 could effectively correct the influence of automatic exposure on DHP and greatly improve its mea-surement accuracy, and provide a technical support for rapid and effective measurement of seasonal changes of LAI in different forest types.

[Construction of empirical models for leaf area and leaf dry mass of two broadleaf species in Xiaoxing'an Mountains, China.] / å°å ´å®‰å²­2ç§é˜”å¶æ ‘ç§å¶é¢ç§¯å’Œå¶å¹²è´¨é‡ç»éªŒæ¨¡åž‹çš„æž„å»º.

Rapid and accurate measurement of leaf area (LA) and leaf dry mass (LM) is one of the basic requirement for leaf geometry and plant functional studies. It is important not only for studying leaf morphology and biomass estimation, but also for understanding the response mechanism of vegetation to climate change. In this study, we took two temperate deciduous broad-leaved tree species, Ulmus laciniata and Acer tegmentosum, as the study objects, constructed empirical models between LA or LM and leaf structure parameters (e.g., leaf length, L; leaf width, W) to reveal the interspecific variability in the selection of empirical model formats (linear or non-linear) and independent variables. We evaluated the forecast accuracy of these empirical models in predicting LA and LM for each species. The results showed that the optimal empirical models for predicting LA were LA=0.614L1.468W0.464 and LA=0.865(LW)0.933, and for predicting LM were LM=0.003L1.537W0.365 and LM=0.001L2.318 for U. laciniata and A. tegmentosum, respectively. The forecast accuracies of empirical models in predicting LA were 88% and 96%, and for LM were 73% and 83% for U. laciniata and A. tegmentosum, respectively. In addition, based on the empirical models for predicting LA and LM, the specific leaf area also could be indirectly measured under non-destructive conditions, with the forecast accuracies being 83% and 90% for U. laciniata and A. tegmentosum, respectively. These results provide a technical support for the efficient measurement of leaf traits and their dynamics.

[Characteristics of Nitrogen Deposition in Heilongjiang Liangshui National Nature Reserve].

To investigate the nitrogen deposition status in Heilongjiang Liangshui National Nature Reserve, a G78 nitrogen deposition collector was used to monitor dry particulate nitrogen deposition and wet nitrogen deposition during the growing season in 2015, and a bucket was used to monitor bulk nitrogen deposition during non-growing season. The results showed that:①Total nitrogen deposition (wet nitrogen deposition+dry particulate nitrogen deposition during the growing season and bulk deposition during the non-growing season) was 12.93 kg·(hm2·a)-1, inorganic nitrogen deposition was 8.27 kg·(hm2·a)-1 with NH4+/NO3- ratio of 1.3; organic nitrogen deposition was 4.66 kg·(hm2·a)-1, which was equivalent to 36.0% of the total nitrogen deposition. ②Total nitrogen deposition in the growing season (wet+dry particulate deposition) and non-growing season (bulk deposition) were 11.42 kg·hm-2 and 1.51 kg·hm-2respectively, which account for 88.3% and 11.7% of the total nitrogen deposition respectively. ③Total wet nitrogen deposition during the growing season was 9.28 kg·hm-2, contributing to 81.3% of the total nitrogen deposition in the growing season, and was positively correlated with precipitation (R2=0.87, P<0.001); total dry particulate nitrogen deposition in the growing season was 2.14 kg·hm-2, which was 18.7% of the total nitrogen deposition in growing season. Wet nitrogen deposition in this region is moderate compared with other regions in China, and is significantly affected by precipitation. There is a potential risk of environmental pollution in this region. Thus, environmental protection and water quality monitoring are required in the process of production.

[Estimation of seasonal changes in leaf area index based on optical methods in spruce-fir valley forest].

The seasonal changes in LAI were respectively measured using digital hemispherical photography (DHP), LAI-2000 plant canopy analyzer (indirect methods) and litter collection method (direct method) in spruce-fir valley forest in the Xiaoxing' an Mountains, China. In addition, we constructed the relationships between LAI from direct method and that from indirect methods in different seasons. The results showed that LAI from DHP underestimated LAI from direct method by 40%-48% in the whole study period, and the underestimation range for LAI-2000 plant canopy analyzer was 15%-26%. LAI from direct method and that from DHP or LAI-2000 plant canopy analyzer all correlated significantly in different seasons, and the relationships between LAI from direct method and that from DHP or LAI-2000 plant canopy analyzer all could be merged into three classified prediction models after testing, i.e., A, B and C, which were able to predict LAI in May and November, June, September and October, and July and August, respectively. This study laid a foundation for effective and accurate measurement of seasonal changes in LAI for coniferous forest in subsequent studies.

[Carbon density and production in valley spruce-fir forest in Xiaoxing'an Mountains, China].

The carbon density and production were measured using both forest inventory and allometry approaches in the declining valley spruce-fir forest in Xiaoxing' an Mountains. Results showed that the total carbon density of the forest was 268. 14 t C · hm(-2) in 2011, and carbon densities of the vegetation, detritus and soil were 74.25, 16.86 and 177.03 t C · hm(-2), respectively. From 2006 to 2011, tree layer carbon density decreased from 80.86 t C · hm(-2) to 71.73 t C · hm(-2). The average decrease proportions per year of carbon density were 0.5%, 1.2%, 2.7% and 3.7% for Abies nephrolepis, Betula platyphylla, Picea spp., and Larix gmelinii, respectively. However, carbon densities were increased by 2.9%, 3.9% and 7.2% per year for Alnus sibirica, Pinus koraiensis and Acer ukurunduense, respectively. Net primary production (NPP) of the forest was 4.69 t C · hm(-2) · a(-1). The ratio of belowground NPP to aboveground NPP was 0.56. Litterfall accounted for the largest proportion of the NPP of forest with a value of 34.5%. As the two most important carbon output approaches of forest ecosystems, the fluxes of heterotrophic respiration and coarse woody debris decomposition were 293.67 and 119.29 g C · m(-2) · a(-1), respectively. Net ecosystem production (NEP) of the forest was 55.90 g C · m(-2) a(-1). The results indicated that the valley spruce-fir forest in the declining state still had a certain carbon sink capacity.

[Effects of topography on seedling regeneration in a mixed broadleaved-Korean pine forest in Xiaoxing'an Mountains, Northeast China].

To explore the responses of forest seedlings to topographic heterogeneity, nine hundreds of 4 m2 (2 m x 2 m) quadrats with perennial seedlings (H > or = 30 cm, DBH < 1 cm) were installed in a 9 hm2 plot in a typical mixed broadleaved-Korean pine forest in Xiaoxing' an Mountains. Based on the investigation data in 2006, 2008, and 2010, the effects of topography on the seedling establishment were studied. There were a total of 26 tree species in these quadrats. In 2006, 2008, and 2010, the total number of the tree seedlings was 4514, 6464, and 5611 individuals x hm(-2), respectively, among which, the seedlings of the top 10 species occupied >90% of the total. Topography had significant effects on the seedling distribution of the 8 major tree species. For Syringa reticulate var. mandshurica, Abies nephrolepis, Acer mono, Ulmus japonica, A. ukurunduense, Tilia amurensis, and A. tegmentosum, the spatial distribution of the seedlings was consistent with that of grown trees; but for Pinus koraiensis, the spatial distribution of seedlings was inconsistent with that of the grown trees. The mortality of S. reticulate var. mandshurica, A. nephrolepis, U. laciniata, A. tegmentosum, and T. amurensis seedlings was significantly correlated with the topography. The recruitment of S. reticulate var. mandshurica, U. japonica, P. koraiensis, A. nephrolepis, Fraxinus mandshurica, A. mono, and T. amurensis seedlings was also significantly correlated with the topography.

[Effects of selective cutting on the carbon density and net primary productivity of a mixed broadleaved-Korean pine forest in Northeast China].

To accurately quantify forest carbon density and net primary productivity (NPP) is of great significance in estimating the role of forest ecosystems in global carbon cycle. By using the forest inventory and allometry approaches, this paper measured the carbon density and NPP of the virgin broadleaved-Korean pine (Pinus koraiensis) forest and of the broadleaved-Korean pine forest after 34 years selective-cutting (the cutting intensity was 30%, and the cutting trees were in large diameter class). The total carbon density of the virgin and selective-cutting broadleaved-Korean pine forests was (397.95 +/- 93.82) and (355.61 +/- 59.37) t C x hm(-2), respectively. In the virgin forest, the carbon density of the vegetation, debris, and soil accounted for 31.0%, 3.1%, and 65.9% of the total carbon pool, respectively; in the selective-cutting forest, the corresponding values were 31.7%, 2.9%, and 65.4%, respectively. No significant differences were observed in the total carbon density and the carbon density of each component between the two forests. The total NPP of the virgin and selective-cutting forests was (36.27 +/- 0.36) and (6.35 +/- 0.70) t C x hm(-2) x a(-1), among which, the NPP of overstory, understory, and fine roots in virgin forest and selective-cutting forest accounted for 60.3%, 2.0%, and 37.7%, and 66.1%, 2.0%, and 31.2%, respectively. No significant differences were observed in the total NPP and the contribution rate of each component between the two forests. However, the ratios of the needle and broadleaf NPPs of the virgin and selective-cutting forests were 47.24:52.76 and 20.48:79.52, respectively, with a significant difference. The results indicated that the carbon density and NPP of the broadleaved-Korean pine forest after 34 years selective-cutting recovered to the levels of the virgin broadleaved-Korean pine forest.

[Health assessment of individual trees in natural Larix gmelinii forest in Great Xing' an Mountains of China].

To integrate the health assessment results of individual trees into the health assessment of subcompartment (or stand) scale could improve the accuracy of subcompartment (or stand) scale health assessment, and realize the coupling process between the individual tree scale and the subcompartment (or stand) scale, providing a theoretical basis for the realization of forest health management. Taking the natural Larix gmelinii forest in Great Xing' an Mountains as the object, a health assessment indicators system of individual trees was established, which included root state, canopy defoliation degree, crown transparency, crown overlap, crown dieback ratio, live crown ratio, crown skewness, and vertical competition index. The principal component analysis (PCA) was employed to eliminate the correlations, the entropy value method was adopted to confirm the weight of each indicator, and the health status of individual L. gmelinii was assessed by fuzzy synthetic evaluation (FSE) method. Based on the health assessment results, a prediction model of the individual tree health was established by discriminant analysis (DA) method. The results showed that the trees in sub-healthy gradation were up to 36.7%, and those in healthy gradation only reached 12.9%. The proportion of the trees in unhealthy gradation exceeded that of the trees in healthy gradation, occupying 21.1% of the total. The prediction accuracy of the established model was 86.3%. More rational and effective management measures should be taken to improve the tree health grade.

[Estimation of leaf area index of three forest types in Xiaoxing'an Mountains of Northeast China].

From early July to early November 2009, the effective leaf area index (LAIe) of secondary Betula platyphylla forest, spruce-fir valley forest, and mixed broadleaved-Korean pine forest in Xiaoxing'an Mountains were measured with Winscanopy2006 Plant Canopy Analyzer, and the LAIe measured in early November and calibrated with the woody-to-total ratio as well as the clumping index (for clumping beyond the shoots) and the needle-to-shoot area ratio (for clumping within the shoots) was derived as the true leaf area index (LAIt). In combining with litterfall method, the LAIt and its seasonal dynamics of the three forest types were estimated. The LAIe of the secondary B. platyphylla forest reached its peak in July, with a value of 2.21, and that of the spruce-fir valley forest and mixed broadleaved-Korean pine forest peaked in August, with the values of 2.57 and 2. 68, respectively. All the three forest types had the highest LAIt in July, with the values of 3.44, 3.86, and 6.93 for the secondary B. platyphylla forest, spruce-fir valley forest, and mixed broad-leaved-Korean pine forest, respectively. In comparison with the method proposed in this study, the peak time LAIe of the secondary B. platyphylla forest, spruce-fir valley forest, and mixed broad-leaved-Korean pine forest obtained by the optical instrument method was underestimated by 33.1%, 32.9% and 66.0%, respectively, and the LAIe of the three forest types in the entire study period was underestimated averagely by -13.2%, 22.8%, and 56.5%, correspondingly.

[Effects of selective cutting on intra- and interspecies competitions among major tree species in mixed broadleaved-Korean pine forest].

Taking a Korean pine (Pinus koraiensis) forest stand 37 years after selective cutting as test object, this paper studied the effects of selective cutting on the intra- and interspecies competitions among the major tree species in the stand. Selective cutting had significant effects on the population structure, distribution pattern, and competition index of the major species. There was a significant negative correlation between the changes of competition index and tolerance index of the tree species (r = -0.8821). The intra-species competition index had significant linear relationships with the aggregation index and the number of individuals. Heliophilous species Betula costata and Tilia amurensis had the largest aggregation index, and their intra-species competitions were stronger than interspecies competitions, being favorable to the coexistence of different species. Selective cutting weakened the competition of P. koraiensis with its companion tree species, while strengthened the competition of heliophilous species with other tree species. After 37 years of selective cutting, P. koraiensis varied little in its competition stress, being helpful to its regular growth. Because of self-thinning, the dominance of B. costata and T. amurensis had somewhat decrease. The competition stress suffered by Abies nephrolepis was weakened, being beneficial to its regeneration.

[Litter decomposition and nutrient dynamics at different succession stages of typical mixed broadleaved-Korean pine forest in Xiaoxing' an Mountains, China].

Taking the mixed leaf litters in broadleaved-Korean pine forests at different succession stages (secondary birch forest, selective cutting forest, and original mixed forest) and the leaf litters of the dominant tree species (Betula costata, Tilia amurensis, and Pinus koraiensis) in these forests in Xiaoxing' an Mountains, China as test objects, this paper studied their remaining rates and nutrient dynamics in October 2006-November 2008 by using decomposition bag method. For all test leaf litters, their remaining rate had an exponential relationship with time. The annual decomposition constant (k) ranged from 0.137 to 0.328, and the time for decomposing 50% (t50%) and 95% (t95%) was 2.340-4.989 years and 9.360-21.796 years, respectively. No significant differences were observed in the decomposition rates of the leaf litters among the forests, but the k value of the mixed leaf litters was decreased in the order of original mixed forest > selective cutting forest > secondary birch forest, while that of the dominant tree species leaf litters had no obvious pattern. During decomposition, the elements C, P, and K in leaf litters released continuously, and the release pattern of C followed linear function, while that of P and K followed a function of higher degree. Element N presented different levels of accumulation, but had no clear pattern.