Table of Content

15 May 2019, Volume 30 Issue 5

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Exploring the history of the management theory and technology of broad-leaved Korean pine (Pinus koraiensis Sieb. et Zucc.)forest in Changbai Mountain Region, Northeast China.

YU Da-pao, ZHOU Wang-ming, ZHOU Li, DAI Li-min

2019, 30(5):  1426-1434.  doi:10.13287/j.1001-9332.201905.004

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Changbai Mountain is located in the eastern mountain forest region of Northeast China, with broad-leaved Korean pine forest (BKF) as the climax vegetation type. The region is rich in species diversity and serves as an important carrier for precious wood production and forest belts in Northeast China. In the recent 120 years, the vast primary forests in Changbai Mountains have almost disappeared, and have been replaced by secondary forests, over-cut forests, and plantations. Since the founding of the People’s Republic of China, the theory and technology of forest management for BKF in Northeast China have gradually improved along with the researches and understanding on the structure and function of BKF, the disputes of Korean pine regeneration characteristics, and the debate about clear cutting and selective cutting. However, the problem of insufficient Korean pine regeneration still exists, and forest management is very extensive. We tried to untangle the management technology trail and research history of BKF in the past 70 years, and to analyze the current forest types and the formation process of the management regulations, with the aim to provide reference for the sustainable management and quality improvement of natural forests in the region.

Stable carbon isotopic characteristics of plant-litter-soil continuum along a successional gradient of broadleaved Korean pine forests in Changbai Mountain, China.

DIAO Hao-yu, WANG An-zhi, YUAN Feng-hui, GUAN De-xin, YIN Hang, WU Jia-bing

2019, 30(5):  1435-1444.  doi:10.13287/j.1001-9332.201905.007

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Stable carbon isotope composition can accurately indicate ecosystem carbon cycling and provide key information for the study of the influence of forest succession on the carbon cycling and carbon sequestration potential. We measured the δ¹³C values and carbon and nitrogen contents of leaf, trunk, root, litter, and soil along a forest successional gradient in Changbai Mountain, which included a middle-aged poplar-birch secondary forest, a mature poplar-birch secondary forest, and an old-growth broad-leaved Korean pine forest. The results showed that leaf δ¹³C reduced with their position from the upper canopy to lower canopy, bark δ¹³C was less than xylem, fine root δ¹³C was less than course root. In contrast to the secondary forests, δ¹³C of the undecomposed litter layer was less than that of the semi-decomposed layer and decomposed litter layer in the broad-leaved Korean pine forest. Soil δ¹³C increased with depth. The ascending order of mean δ¹³C was leaf, litter, root, trunk, and soil, indicating that there is obvious fractionation among different organs of plants and among different parts of a specific organ. In addition, plant δ¹³C first decreased and then increased with the succession process, but soil δ¹³C increased with the succession processes. The different patterns of the changes of plant and soil δ¹³C along forest succession could be explained by the relationship between nitrogen content and carbon isotope fractionation effect, indicating that carbon isotope fractionation was affected by the change of dominant tree species and the variation of carbon turnover rate.

Effects of nitrogen and soil microbe on growth and photosynthesis of Fraxinus mandschurica seedlings.

WANG Guo-jie, LIN Fei, HU Jia-rui, YUAN Zuo-qiang, HAO Zhan-qing, WANG Xu-gao

2019, 30(5):  1445-1462.  doi:10.13287/j.1001-9332.201905.018

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We examined the effects of nitrogen, soil microbe and their interactions on biomass allocation, growth and photosynthesis of Fraxinus mandschurica, a typical tree species in Changbai Mountain, through outdoor control experiments. In June 2017, an experiment with two-factor randomized block design was carried out. There were four treatments: control (F), nitrogen addition (FN), sterilization (FS), sterilization and nitrogen addition (FSN), six repetitive blocks, three repetitions per block, including 18 repetitions of each treatment. In mid-August 2018, we measured photosynthetic parameters and then harvested seedlings to measure biomass and growth parameters in September. The results showed that compared with F, FN significantly increased total biomass by 14%, basal diameter by 9%, chlorophyll content, net photosynthetic rate (P_n), stomatal conduc-tance (g_s), transpiration rate (T_r) by 75%, 318%, 231%, 227% respectively. FS significantly increased total biomass by 13%, basal diameter by 9% and chlorophyll content, P_n, g_s and T_r increased by 34%, 213%, 120% and 115%, respectively. FSN increased total biomass by 23%, basal diameter by 14%, chlorophyll content, P_n, g_s and T_r increased by 81%, 672%, 312% and 273%, respectively. Nitrogen, soil microbe and their interactions had significant effects on biomass, growth and photosynthesis of F. mandschurica seedlings. Soil microbe would regulate the response of F. mandschurica seedlings to nitrogen.

Differences of leaf dark respiration and light inhibition between saplings and mature trees of Pinus koraiensis and Tilia amurensis.

SUN Jin-wei, YAO Fu-qi, ZHANG Zhen-hua

2019, 30(5):  1454-1468.  doi:10.13287/j.1001-9332.201905.008

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Leaf dark respiration is an important component of carbon cycle. Understanding the differences of leaf dark respiration and light inhibition between saplings and mature trees is important for accurate estimation of ecosystem gross primary productivity (GPP). We meansured leaf dark respiration of saplings and mature trees of two dominant species (Pinus koraiensis and Tilia amurensis) in light and in darkness in the broadleaved-Korean pine mixed forest on Changbai Mountain. Differences of leaf dark respiration, light inhibition and leaf physiological and ecological parameters between saplings and mature trees were analyzed. The reason of differences on leaf dark respiration and the light inhibition were explored. The results showed that leaf dark respiration of saplings of two species under light was 6.8%-39.6% higher than that of mature trees in growing season. Light inhibition of leaf dark respiration in saplings was 2.5%-14.1% lower than in mature trees. The difference of light inhibition of leaf dark respiration between saplings and mature trees of P. koraiensis was higher than that of T. amurensis, with a maximum difference of 18.6%. The higher leaf dark respiration and lower light inhibition degree in saplings might result from the changes of max net photosynthesis rate, specific leaf area, and stomatal conductance, instead of leaf nitrogen content.

Effects of nitrogen addition on biomass allocation of Pinus koraiensis and Fraxinus mandshurica seedlings under water stress.

CUI Wan-ying, LIU Si-jia, WEI Ya-wei, YIN You, ZHOU Li, ZHOU Wang-ming, YU Da-pao

2019, 30(5):  1463-1453.  doi:10.13287/j.1001-9332.201905.027

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Nitrogen deposition and climate warming-drying are the main environmental changes in Northeast China. How they affect forest ecosystems has always been studied in ecological research. In this study, we explored the effects of water stress and nitrogen (N) addition on the short-term (in 55 weeks) growth of seedlings of Pinus koraiensis and Fraxinus mandshurica, two key species in broad-leaved and P. koraiensis mixed forests in temperate zone of Northeast China. Results showed that the responses of seedling growth of P. koraiensis and F. mandshurica to nitrogen addition and water stress were significantly different. P. koraiensis was more sensitive to water stress. In the early stage (in 10 weeks) of water stress, leaf biomass of P. koraiensis significantly decreased while the root biomass increased. Nitrogen addition significantly reduced the root and total biomass of P. koraiensis under water stress. F. mandshurica was more sensitive to N addition. Nitrogen addition rapidly increased the stem, root and total biomass of F. mandshurica. Only sustained water stress could significantly affect the stem, root and total biomass of F. mandshurica. Under continuous water stress and N addition, the biomass contribution of leaves and roots to whole seedling, and the ratio of aboveground to underground biomass of both species tended to be constant, indicating strong self-regulation ability of both species. The results suggested that when drought occurred in the future, P. koraiensis would adopt a “positive” adjustment strategy, while F. mandshurica would adopt a “passive” response. The survival rate and adaptability of P. koraiensis would be higher than F. mandshurica. F. mandshurica would benefit more from N deposition than P. koraiensis. Our results are helpful for predicting the changes of community structure in temperate forest in Northeast China.

Competition of key tree species with selective cutting at different intensities in broadleaved-korean pine mixed forest in the Changbai Mountain, China.

TANG Yang, CHEN Hong, TONG Yue-wei, ZHU Qi, ZHOU Wang-ming, ZHOU Li, DAI Li-min, YU Da-pao

2019, 30(5):  1469-1478.  doi:10.13287/j.1001-9332.201905.017

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Selective cutting changes tree species composition and stand structure, modifies tree competition intensity in the stand, with consequences on tree growth and population dynamics. Key tree species play a crucial role in maintaining community structure and ecosystem function. To clarify the competitive characteristics of three key species (Pinus koraiensis, Tilia amurensis, and Fraxinus mandshurica, which accounted for about 70% of growing stock) of typical forest types in broadleaved-Korean pine mixed forest, Hegyi competition index was used in four permanent 1-hm² plots, i.e. virgin forest (VF), low-intensity cutting forest (LCF), moderate-intensity cutting forest (MCF) and high-intensity cutting forest (HCF). Compared with VF, the stand density and mean DBH of big trees (DBH≥20 cm) significantly decreased in MCF and HCF, but the stand density of young trees (2 cm≤DBH<10 cm) increased, but no significant changes of stand or DBH in LCF. In all the four forest types, individual competition index (CI) of the three species decreased with increasing DBH. There was a power function relation between CI and DBH. CI curve turned to be gentle at DBH reaching 20 cm, and this rule was not affected by selective cutting. In VF, LCF and HCF, most of competition pressure of young trees of all key species derived from other tree species in secondary canopy or understory, but the competition pressure of small trees (10 cm≤DBH<20 cm) and big trees of P. koraiensis originated mainly from intra-species and other species in secondary canopy or understory. The competition stress of F. mandshurica was mainly affected by P. koraiensis and other species in secondary canopy or understory. T. amurensis was mainly affected by intra-species and P. koraiensis. Betula platyphylla contributed most of the competition stress (over 50%) to all three key species in HCF. Our results suggested that removing the trees which are in secondary canopy or understory but suppress the three key trees species intensively would be beneficial to the regeneration and growth of key species before tree DBH exceeds 20 cm. We proposed to regulate the density of key tree species in overstory to cultivate large diameter timber according to the competition among the key trees species. Once tree DBH exceeds 20 cm, tree growth would not be affected by competition. This study had guiding significance for the cultivation of key tree species and rapid recovery of natural forests after selective cutting.

Effect of neighborhood competition on key tree species growth in broadleaved-Korean pine mixed forest in Changbai Mountain, China.

TANG Yang, TONG Yue-wei, HAN Yan-gang, ZHOU Wang-ming, ZHOU Li, DAI Li-min, YU Da-pao

2019, 30(5):  1479-1486.  doi:10.13287/j.1001-9332.201905.021

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Competition is the main factor affecting the growth, morphology and death of trees in fore-sts. The analysis of individual competition can reflect the characteristics of interaction among individuals and their interaction ranges, which is important for reducing individual competition and promoting tree growth. To understand the effects of competition on tree growth in broad-leaved Korean pine forest, based on Hegyi single-tree competition index and neighborhood analysis method, we explored the neighborhood radius of competition for five key tree species, i.e. Pinus koraiensis, Tilia amurensis, Fraxinus mandshurica, Quercus mongolica and Ulmus japonica (80% of basal area at breast height in total), and analyzed the effects of competition on the growth and death of the key tree species. The results showed that the neighborhood radius of single-tree competition of four tree species, P. koraiensis, T. amurensis, F. mandshurica and Q. mongolica was 11 m, while that of U. pumila was 13 m. The single-tree competition intensity for all five key tree species was negatively correlated with the logarithm of its growth increment, and positively correlated with the size of individual trees. The relative importance of competition intensity on tree growth decreased with tree growth. Neighborhood competition significantly increased tree mortality. Our results revealed the effects of neighborhood competition on the growth and survival of the key tree species at different developmental stages in broad-leaved Korean pine forests in Changbai Mountain. The results are instructive to the adjustment of competitive environment and the improvement of productivity of key tree species in broad-leaved Korean pine forests.

Spatio-temporal dynamics of woody plants seed rains in broad-leaved Korean pine mixed forest in Changbai Mountains form 2006 to 2017, China.

QIAN Duo-duo, KUANG Xu, WANG Xu-gao, LIN Fei, YUAN Zuo-qiang, YE Ji, HAO Zhan-qing

2019, 30(5):  1487-1493.  doi:10.13287/j.1001-9332.201905.012

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Seeds are the basis for forest regeneration. To examine the composition and spatio-temporal dynamics of seed rains, a total of 150 seed traps of 0.5 m² were installed in a 25 hm² broad-leaved Korean pine (Pinus koraiensis) mixed forest plot in Changbai Mountains. With a total of 252 collections from May 2006 to September 2017, we collected 764299 mature and immature seeds which were belonged to 27 species, 17 genera, and 12 families. More than 90% of all collected seeds (704231 seeds) were from 13 canopy species. Seeds of four tree species, including Tilia amurensis, Fraxinus mandschurica, Acer mono, and Acer pseudo-sieboldianum could be collected every year from each trap. Mast-seeding was found in every canopy layer, but it happened one to two years earlier in the overstorey layer than midstorey and understorey layer. Almost all species produced seeds in autumn, with considerable spatiotemporal variation. Generally, the spatial variation of seeds was larger than temporal variation. Compared with annual variation coefficient of seeds in tropical forest of the Barro Colorado Island (BCI) and subtropical evergreen forest in the Gutianshan, annual variation coefficient of seeds in Changbai Mountains was higher, which supported the hypothesis that annual variation in seed rains would be lower in the tropics than that in higher latitudes.

In-situ measurement of photosynthetic characteristics of dominant tree species based on canopy crane in a Korean pine broad-leaved forest in Changbai Mountain, northeastern China.

LIANG Xing-yun, LIU Shi-rong

2019, 30(5):  1494-1502.  doi:10.13287/j.1001-9332.201905.015

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To better understand the eco-physiological characteristics of dominant tree species in Korean pine broad-leaved forests, and to provide fundamental data for modelling and predicting carbon dynamics of forest ecosystems, we measured leaf CO₂ assimilation rate versus intercellular CO₂ concentration curves of four canopy dominant tree species in a Korean pine broad-leaved forest, in situ, for the first time, using a canopy crane in the Changbai Mountain Forest Ecosystem Research Station. Several important photosynthetic parameters were fitted with the FvCB model. Photosynthe-tic rate (A), maximum carboxylation rate (V_{c max}) and stomatal conductance (g_s) were lowest in Pinus koraiensis (Pk), while stomatal limitation on photosynthesis (L_s) was highest in Pk. There were significant variations of photosynthetic characteristics among the three broad-leaved tree species [i.e., Fraxinus mandshurica (Fm), Quercus mongolica (Qm) and Tilia amurensis (Ta)]. The rank of tree species with respect to area-based V_{c max} was: Fm (83.2 μmol·m^-2·s^-1) and Qm (89.3 μmol·m^-2·s^-1) > Ta (68.4 μmol·m^-2·s^-1) and Pk (68.8 μmol·m^-2·s^-1) (P<0.05), and their rank with respect to mass-based V_{c max} was: Fm (1.36 μmol·g^-1·s^-1) > Qm (1.03 μmol·g^-1·s^-1) > Ta (0.90 μmol·g^-1·s^-1) > Pk (0.42 μmol·g^-1·s^-1) (P<0.05). From July to September, A value significantly declined in Fm and Qm, but remained stable in Ta and Pk. By contrast, V_{c max} significantly decreased in all tree species from July to September. Our results indicated that seasonal variation of V_cmax should be taken into consideration in the modelling and predicting of forest ecosystem carbon dynamics in northeastern China.

Characteristics of climate change in Changbai Mountain ecological functional area, Northeast China.

LIU Ya-ge, YUAN Feng-hui, WANG An-zhi, WU Jia-bing, ZHENG Xing-bo, YIN Hang, GUAN De-xin

2019, 30(5):  1503-1512.  doi:10.13287/j.1001-9332.201905.006

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We integrated the meteorological records from 36 national weather stations and CN05.1 gridded daily observation dataset to analyze the climate change characteristics of Changbai Mountain eco-functional area. Linear tendency estimation, Mann-Kendall mutation test, cumulative anomaly method and Morlet wavelet analysis were used to investigate the temporal and spatial variation of temperature (annual temperature, seasonal temperature, extreme temperature), moisture (annual precipitation, seasonal precipitation, relative humidity), radiation (sunshine duration, sunshine percentage) and wind speed from 1961 to 2016. The results showed that, during 1961-2016, the temperature of this area increased, the radiation and wind speed decreased, and the precipitation varied periodically. Specifically, winter temperature [0.45 ℃·(10 a)^-1] and the lowest temperature [0.74 ℃·(10 a)^-1] significantly increased. The mean annual wind speed significantly decreased [-0.21 m·s^-1·(10 a)^-1]. No abrupt climate change was observed. The annual precipitation days decreased considerably [-7.01 d·(10 a)^-1], which was different from the climate change pattern of Northeast China. The annual precipitation trend coefficient of this area was 16.06 mm·(10 a)^-1 , which could not be simply depicted by increase or decrease in trend. The precipitation change in this area was dominated by periodically patterns, and the period was 26 years and 3 years. Our results would be instructive to the regional ecological assessment, and the research on ecosystem responses to climate change and phenological changes.

Tree radial growth-climate relationship in Changbai Mountain, Northeast China.

HAN Yan-gang, ZHOU Wang-ming, QI Lin, ZHOU Li, ZHONG Qing-lin, DAI Li-min, YU Da-pao

2019, 30(5):  1513-1520.  doi:10.13287/j.1001-9332.201905.039

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Changbai Mountain is one of the hotspots for tree ring research in Northeast China, with a large number of related research results having been published. To clarify the advance of tree ring research in Changbai Mountain and understand the responses of tree radial growth to climate factors, we reviewed the related literature and analyzed the differences among them based on tree species identity, elevation, and detrended methods. The radial growth of trees in Changbai Mountain was generally affected by temperature and precipitation, with greater influence of temperature. The relationship between tree radial growth and climate variables varied across both species and altitudes. Most studies reported that the radial growth of conifers were mainly affected by temperature in early growing season (April-May) and growing season precipitation (June-August). The radial growth of broadleaved trees were mainly affected by the temperature in previous and current growing season, the precipitation in dormancy season (November-March), and the precipitation in the current growing season. The previous September precipitation had significant effects on the radial growth of conifers and broadleaved trees. However, many studies had reported different or even opposite results. Most of the differences in the results of the studies appeared at low and medium altitudes, indicating that the altitudinal location of sampling points had impacts on the results. In addition, the detrended method was also the main cause for the variation of results across different studies. Comparatively, the linear or negative exponential detrended method might increase the effective significance of precipitation, especially the effect of precipitation on tree growth during dormancy period, and also strengthen the effective significance of the temperature at the end of the growing season. This study showed the habitat and the detrended method used in chronology were the main reasons for the difference of results among the studies. Therefore, for tree ring research in Changbai Mountain, the number of sampling sites should be increased and the detrended method should be carefully selected.

Regulation effects of temperate broadleaved Korean pine forest on temperature and humidity in Changbai Mountain, China.

WANG Pei-huan, CHEN Zhi, YU Gui-rui, WANG Qiu-feng, JIA Yan-long, HAN Shi-jie

2019, 30(5):  1521-1528.  doi:10.13287/j.1001-9332.201905.023

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Forests can improve climate and regulate micro-environment. The study of forest micro-climate is of great significance to reveal forest ecosystem function and evaluate the benefits of forest ecological environment. With broadleaved Korean pine forest in Changbai Mountain as test material, the diurnal and seasonal variations of the mean, maximum and minimum temperature, relative humidity and surface soil temperature were analyzed based on the meteorological data of flux tower in the forest and nearby meteorological station in the open land from 2003 to 2014. The results showed that air temperature and relative humidity in the forest showed a unimodal U-shaped diurnal pattern, respectively. The diurnal range was 2.31 ℃ and 8.3% lower than that of the open land. The diurnal surface soil temperature tended to be a constant, indicating an alleviating effects of broadleaved Korean pine forest on the diurnal variation of temperature and moisture. The cooling effect was mainly observed in summer, while the warming effect was significant in winter. The air and soil temperatures in forest in summer were 1.30 and 3.91 ℃ lower than those in the open land, and were 2.06 and 5.44 ℃ higher than those in the open land in winter. Forest regulated the maximum and minimum temperatures significantly. On the season scale, the maximum air and soil temperature in forest decreased by 1.80 and 5.45 ℃ in summer, while the minimum air and soil temperature increased by 3.69 and 7.92 ℃ in winter. On the annual scale, the maximum air and soil temperature in forest were 1.60 and 4.99 ℃ lower than those in the open land, and the minimum air and soil temperature were 1.12 and 8.82 ℃ higher than those in the open land, respectively. The regulating effects of forests on soil temperature was stronger than that on air temperature. Forests mainly warmed the air and soil temperature at cold condition.

Interspecific difference of relationship between radial growth and climate factor for Larix olgensis and Picea jezoensis var. komarovii in Changbai Mountain, Northeast China.

WANG Shou-le, WANG Xiao-yu, GAI Xue-rui, DAI Li-min, ZHOU Wang-ming, ZHOU Li, YU Da-pao

2019, 30(5):  1529-1535.  doi:10.13287/j.1001-9332.201905.028

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To clarify the responses of radial growth of different tree species to climate change and its stability, we explored the relationships between radial growth and climate factors of larch (Larix olgensis) and spruce (Picea jezoensis var. komarovii) distributed at high altitude (1600-1750 m) on the northern slope of Changbai Mountain, using the chronological method. The results showed that the growth of larch was significantly positively correlated with the maximum temperature in June and negatively correlated with the precipitation in June. The radial growth of spruce was significantly positively correlated with the maximum temperature in May. Results from redundancy analysis showed that larch growth was mainly affected by summer temperature, while spruce growth was significantly restricted by spring temperature. During 1959-2014, the relationship between larch growth and summer temperature was relatively stable. For spruce, the correlation between radial growth and spring temperatures had gradually weakened since 1986, mainly due to the growth slowdown because of decreased maximum air temperature. Our results provide theoretical references for predicting the growth response of conifers at Changbai Mountain region in the context of climate change.

Responses of soil carbon and nitrogen mineralization to nitrogen deposition in tundra zone of the Changbai Mountain, China.

CHEN Hong, TANG Yang, TONG Yue-wei, ZHU Qi, ZHOU Wang-ming, ZHOU Li, YU Da-pao, DAI Li-min

2019, 30(5):  1536-1542.  doi:10.13287/j.1001-9332.201905.013

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The alpine tundra ecosystem, with low soil inorganic nitrogen (N) availability, has a weak buffer against nitrogen and is susceptible to exogenous N enrichment. Here, with a laboratory incubation experiment, we investigated the response of soil carbon and nitrogen mineralization to N deposition with soil samples from the tundra zone on the northern slope of the Changbai Mountain. We set three N levels, control (CK, 0 kg·hm^-2), low N (N₁, 25 kg·hm^-2), and high N (N₂, 50 kg·hm^-2), with N being added as NH₄NO₃. The results showed that N addition had no significant effect on soil C mineralization rate, but significantly affected the accumulation of soil C minera-lization. The N₂ treatment inhibited soil C mineralization. After the 40 d incubation, soil inorganic N content increased with increasing N addition. After the 80 d incubation, soil inorganic N content in the N₂ and N₁ was similar and significantly higher than that of CK. Those results indicated that N addition promoted soil N mineralization. The soil microbial biomass C and N in the N₁ was higher than that in the N₂ and CK, indicating that low N input had stronger effects on soil microbial activity. Increasing N deposition might accelerate C and N turnover in the tundra soils and enhance the soil inorganic N content. While it could provide more N for plants, it may increase the risk of N loss.

Effects of nitrogen deposition on carbon and nitrogen contents in soil aggregates in temperate forests of Changbai Mountain, Northeast China.

ZHOU Xue-ya, CHEN Zhi-jie, GENG Shi-cong, ZHANG Jun-hui, HAN Shi-jie

2019, 30(5):  1543-1552.  doi:10.13287/j.1001-9332.201905.025

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Nitrogen deposition is one of the most important factors affecting carbon (C) and nitrogen (N) cycling in terrestrial ecosystem. A six-year N addition experiment was carried out to explore how N deposition affected C and N fractions in soil aggregates in the secondary aspen forest (YHL) and primary Korean pine broad-leaved forest (HSL). We investigagted the effects of N addition on dissolved organic carbon and nitrogen (DOC and DON), microbial biomass carbon and nitrogen (MBC and MBN), particulate organic carbon and nitrogen (POC and PON) in soil aggregates with different particle sizes. The results showed that the contents of carbon and nitrogen fractions generally increased with the decrease of particle sizes of soil aggregates except for POC and PON. In soil aggregates of HSL, POC and PON significantly decreased by 20.7% and 22.6% in N treatment, respectively, but DOC increased by 11.6%. In YHL, N addition treatment had no signi-ficant effect on C and N fractions in soil aggregates. Total carbon or nitrogen correlated well with the active C and N fractions in soil aggregates, with a great significant negative correlation between POC and DOC in HSL (r=-0.503) and a significant positive correlation between DOC and MBC (r=0.462). In HSL, the negative effect of N treatment on POC and PON and the positive effect on DOC was mainly attributed to the accelerated decomposition of POM by stimulating microbial activity. Soil C and N pools in HSL were more vulnerable to N deposition than that in YHL.

Changes of soil aggregate size composition and organic carbon content at different succession stages of broad-leaved Korean pine forest in Changbai Mountain, China.

ZHENG Xing-bo, ZHANG Xue, HAN Shi-jie

2019, 30(5):  1553-1562.  doi:10.13287/j.1001-9332.201905.009

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The broad-leaved Korean pine forest is an important primary forest in Northeast China. Soil aggregates play important role in carbon fixation of forest ecosystem. Temporal-spatial substitution method was used in this study. We selected five forests with different succession stages: birch young forest, birch middle forest, birch mature forest, mature broad-leaved Korean pine fore-st, and over-mature broadleaved Korean pine forest. The distribution of soil aggregate particle size and agglomeration in organic carbon under different forests were investigated by wet sieving method. The results showed that soil aggregate size distributions and the proportions of soil aggregates were significantly different among succession stages. The mean mass diameter of aggregates was generally showed a unimodal trend along with the succession stages, peaking at birch mature forest stage. The organic carbon content in the aggregate of different particle-sizes in the soil increased firstly and then decreased slightly from early to late succession, and the maximum content of organic carbon in the aggregate was in broad-leaved Korean pine mature forest stage. Under the same succession stage, the content of organic carbon in the aggregate of different particle-sizes increased with the decreases of the particle size in the soil depth of 0 to 5 cm and 5 to 10 cm (except over-mature broad-leaved Korean pine forest at the end of succession), but it was the opposite in the soil depth of 10 to 20 cm. From the birch young forest at the early stage of succession to the over-mature broad-leaved Korean pine forest at the end of succession, organic carbon content in the aggregate of same particle-size had obvious vertical distribution characteristics, which significantly decreased with the increases of soil depth.

Quantitative characteristics and population dynamics of the endangered plant Thuja koraiensis in Changbai Mountain, China.

JIN Hui, ZHAO Ying, LIU Li-jie, JIA Xiang, DAI Yu-hong, QIN Li-wu, WANG Chao, YIN Hang

2019, 30(5):  1563-1570.  doi:10.13287/j.1001-9332.201905.019

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Thuja koraiensis, a second-class nationally protected plant species, is a unique endangered tree species in Changbai Mountain, with important economic and ornamental value. In this study, the age structure, static life table, and survival function of T. koraiensis were established by using individual root diameter and age data based on investigation of wild resources in the main distribution areas of T. koraiensis. The population development trend was predicted by dynamic index and time series analysis. The results showed that the age-class structure of T. koraiensis population was in the shape of “∩”, which was a decline type. The survival curve of T. koraiensis population under the dark coniferous forest was the Deevey-Ⅲ type, and was Deevey-Ⅱ type in pure forest community. Population survival analysis showed that the survival function of T. koraiensis appeared irregular fluctuation under the dark coniferous forest. The population distribution showed dynamic features of sharp drop in early age period, stable in middle age period, and decline in old age pe-riod. In the pure forest community, the dynamic pattern was characterized by the stability in early age period, growth in middle age period, and recession in old age period. Dynamic index and time series analysis showed that the decline rate of dark coniferous forest community was slightly higher than that of pure forest community. Our results showed that T. koraiensis had some recovery ability and that artificial tending should be used to promote its normal regeneration.

Community structure characteristics and spatial distribution of dominant species of secondary Quercus mongolica forest in Changbai Mountains, China.

ZHANG Xiao-hong, ZHANG Hui-ru, LU Jun, HU Xue-fan

2019, 30(5):  1571-1579.  doi:10.13287/j.1001-9332.201905.010

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Understanding forest community structure is the basis for revealing community maintenance mechanism and succession dynamics, and the premise forest management activities. Taking two permanent 1-hm² plots of Quercus mongolica broadleaved mixed forest located in Wangqing Fore-st Bureau in Jilin Province as objects, we analyzed the community structure characteristics of secondary Q. mongolica forest and spatial distribution of dominant species with the point pattern analysis method (the O-ring statistics). The results showed that both plots were dominated by Q. mongo-lica with distinct hierarchy character. The co-dominated trees in plot I were Populus ussuriensis, Be-tula platyphylla, and Pinus koraiensis, which were different from plot II (Tilia amurensis, Acer mono, and Pinus koraiensis). The richness and Shannon index of plot I were higher than that of plot II. The DBH class distribution of trees in both plots were reverse-J-shaped. Individuals of Q. mongolica exhibited a normal distribution and P. koraiensis showed a reverse-J-shaped. There were differences in the diameter structure of other co-dominant tree species. The spatial distribution of Q. mongolica in two plots was aggregation distribution at small scale and random distribution in medium and large scales. P. koraiensis showed aggregation-random distribution at 0-50 m scale, while its aggregation degree in plot I were higher than that of plot II. B. platyphylla and P. ussuriensis in plot I were aggregated at the scale of 0-17 m, and the aggregation intensity was significantly higher than other tree species, and showed random distribution and uniform-random distribution at the scale of 18-50 m, respectively. Random or uniform distribution at the medium-large scale, and aggregate distribution at small scale of T. amurensis were observed in plot II. These results demonstrated that both plots were at the primary stage of succession with different growth stages. The succession stage of plot II was more progressed than that of plot I and the community of plot II was relatively more stable. Our results provide references for the precise management of Q. mongolica secondary forests at different developmental stages.

Vegetation damage, post-disaster change degree and driving factors in the cold temperate wind disaster area of Changbai Mountain, China.

WANG Hui-yun, ZHANG Ying-jie, JIN Ying-hua, XU Jia-wei, TAO Yan, HE Hong-shi, GAO Xiang, BAI Yun-yu, HU Rui, HAN Ying-ying

2019, 30(5):  1580-1588.  doi:10.13287/j.1001-9332.201905.026

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The typhoon outbreaks of 1986 caused many gaps in the cold temperate coniferous forest and Betula errmanii forest on the western and southern slopes in the Changbai Mountain. In 2017, a research area at the 1600-1800 m altitude in Changbai Mountain was established to explore the damage and changes of forest vegetation disturbed by the typhoon in cold temperate zone and to reveal the regulation of damage on vegetation and post-disaster change as well as the driving factors. The remote sensing data were used to classify research area based on the degree of vegetation damage and post-disaster change. A total of 40 plots were set up for vegetation survey. According to the damage degree of forest structure, three levels of severity of damage to vegetation in the cold temperate zone of Changbai Mountain were classified including gently, moderately, and severely damaged, in which moderately damaged area was largest, followed by gently damaged area and severely damaged area. Tree damage significantly differed among three level areas, with 20%, 50% and 85% reduction of the abundance of dominant trees in gently, moderately and severely damaged areas, respectively. The wind resistance ability of B. errmanii was higher than that of Picea jezoensis. The wind resistance ability of B. errmanii with larger diameter grade was higher than that of those with smaller diameter grade. The severity of damage to vegetation was strongly correlated with slope, with lower severity on the steeper slop area. From 1987 to 2017, the vegetation of wind disaster area significantly changed. The study area could be classified into three levels based on the degree of changing: fast, medium, and slow, with largest area in medium changed, followed by slowly and fast changed. The degree of vegetation changes was strongly correlated with altitude, with slower change at higher altitude area. The recovery rate of trees was slow, with P. jezoensis recovering slightly quicker than B. errmanii. The vegetation change mainly occurred in shrub and herb layers. Shrub layer recovered better than the herb layer in the fast changed area, while herb layer recovered better than the shrub layer in the medium changed area. In the slowly changed area, herb layer was generally low and dense with varying shrub layer.

Dynamics of gross primary productivity with VPM model in Changbai Mountain Natural Reserve, Northeast China.

PING Xiao-ying, MA Jun, LIU Miao, CHANG Yu, ZONG Min, XIONG Zai-ping

2019, 30(5):  1589-1598.  doi:10.13287/j.1001-9332.201905.029

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Precise estimation of gross primary productivity (GPP), the key parameter in carbon cycle analysis, plays an important role in the research of carbon cycle and global climate change. Vegetation GPP was simulated by VPM model based on MOD09A1 and climate data in Changbai Mountain Natural Reserve from 2000 to 2015. The results showed that mean GPP was 1203 g C·m^-2·a^-1. The annual vegetation GPP significantly increased from 2000 to 2015. There was no significant difference in the temporal trends of forest GPP at different vertical vegetation zones. However, GPP of the alpine tundra decreased remarkably. The correlation between GPP and precipitation was not significant. The positive correlation of GPP and temperature was mainly distributed in broad-leaved Korean pine forests and alpine tundra. Spring temperature had the strongest influence on GPP, with 80% pixels had a positive correlation with temperature. The GPP had a stronger correlation with temperature compared with precipitation.

Application of 3PG carbon production model in the gross primary productivity estimation of broadleaved Korean pine forest in Changbai Mountain, China.

CHANG Xiao-qing, XING Yan-qiu, WANG Xin-hui, YOU Hao-tian, XU Ke

2019, 30(5):  1599-1607.  doi:10.13287/j.1001-9332.201905.037

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With the flux data of ChinaFLUX and the concurrent satellite remote sensing data in Changbai Mountain, we recombined parameters of four models, i.e., vegetation photosynthesis model (VPM), eddy covariance-light utility efficiency model (EC-LUE), terrestrial ecosystem model (TEM) and Carnegie-Ames-Stanford approach model (CASA) within 3PG model. The most suitable parameters of 3PG model were determined by comparing the root mean square error, coefficient of determination and average error between measured and observed flux values. To improve its accuracy in estimating gross primary productivity (GPP) of broadleaved Korean pine forest in Changbai Mountain, the fitness of the optimal model was validated using the observed flux data. The results showed that when temperature, enhanced vegetation index, and surface water index were used to characterize the temperature limiting factor, photosynthetic active radiation absorption ratio and water limiting factor in the original model to estimate GPP of broadleaved Korean pine forest, the simulation results were the best. The precision of the optimized model (R²=0.948, RMSE=0.035 mol·m^-2·month^-1) was better than that of the original model (R²=0.854, RMSE=0.177 mol·m^-2·month^-1), which could effectively improve the phenomenon of obvious overestimation of the original model in the growing season. Results from the parameter sensitivity analysis showed that the uncertainty of GPP estimation was dominated by temperature, followed by enhanced vegetation index, photosynthetically active radiation and land surface water index, as well as their interactions.

Characteristics of non-structural carbohydrate reserves of three dominant tree species in broadleaved Korean pine forest in Changbai Mountain, China.

WANG Xiao-yu, WANG Shou-le, TANG Yang, ZHOU Wang-ming, ZHOU Li, ZHONG Qing-lin, DAI Li-min, YU Da-pao

2019, 30(5):  1608-1614.  doi:10.13287/j.1001-9332.201905.001

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Non-structural carbohydrates (NSC, including soluble sugars and starch) are key meta-bolites in tree, the storage characteristics of which in tree organs have received extensive attention. It is still unclear how NSC are allocated in the tissues (phloem and xylem) that have different function. In this study, we analyzed the concentration and allocation of NSC in the roots, and in phloem and xylem of the trunk in three dominant species of broadleaved Korean pine forest in the Changbai Mountain, Pinus koraiensis, Fraxinus mandschurica, and Tilia amurensis. The results showed that there was a significant difference in the concentration of NSC between the phloem and xylem. The soluble sugar dominated in the phloem, while starch dominated in the xylem. The concentration of NSC in trunk outside (divided by annual rings, 0-20 years), intermediate (20-40 years) and inner (>40 years) of different tree species was significantly different, but with no difference in the roots. The total soluble sugar concentration in the phloem of P. koraiensis and F. mandschurica was significantly higher than that of T. amurensis, while the difference in xylem was not significant. The results indicated that NSC allocation in the phloem and xylem of the tree had clear tissue differentiation, which might be related to the succession stage of the tree species or the functional evolution of the tissue. These findings would improve our understanding of the carbon storage characteristics and allocation mechanism in temperate trees.

Co-accumulation characters of soil organic carbon and nitrogen under broadleaved Korean pine and Betula platyphylla secondary forests in Changbai Mountain, China.

ZHAO Hua-chen, GAO Fei, LI Si-wen, GAO Lei, WANG Ming-zhe, CUI Xiao-yang

2019, 30(5):  1615-1624.  doi:10.13287/j.1001-9332.201905.040

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The retrogressive succession is an important driver for dynamics of soil organic carbon (SOC) and total nitrogen (TN). We studied the quantitative distribution and synergistic accumulation characteristics of soil organic carbon and nitrogen in the primary broadleaved Korean pine (KP) forest and Betula platyphylla (BP) secondary forest in Changbai Mountain through paired plot approach. Further, we analyzed the changes of carbon pool and carbon sink effect in temperate forest soil caused by secondary succession and their carbon-nitrogen coupling mechanism. The results showed that the BP forest accumulated more organic carbon and nitrogen in the surface and subsurface soil (0-20 cm) than the KP forest, with relatively low soil C/N. Compared with KP forest, soil organic carbon storage in BP forest (0-20 cm) was higher by 14.7 t·hm^-2, equivalent to a soil carbon sink gain of 29.4 g·m^-2·a^-1. SOC and TN concentrations were positively correlated in each soil layer of all forest types, causing a co-accumulative relationship between SOC and TN. The coefficient of determination (R²) between SOC and TN in the upper soil layers of BP forest was significantly higher than that of the KP forest, indicating that SOC accumulation under the relatively N-rich BP forest was more dependent on the accumulation of organic nitrogen. In the upper soil layers (0-10 cm) where organic matter concentrated, there was no significant difference in light fraction organic carbon and nitrogen stock between the two forest types, whereas the content, stock, and allocation percentage of heavy fraction organic carbon and nitrogen of BP forest were all significantly higher than that of the KP forest, with an average increment of 8.5 t·hm^-2 in heavy fraction organic carbon stock. Those results indicated that the increase of soil organic carbon and nitrogen during secondary succession was mainly due to the increases of soil organic carbon and nitrogen pools in mineral-bound stability. The carbon-nitrogen coupling mechanisms in litter decomposition and soil organic matter formation was an important driving mechanisms underlying the changes of soil organic carbon and nitrogen pools during secondary succession.

Spatiotemporal variation of productivity and carbon use efficiency of forests in Northeast China from 2000 to 2015.

CHEN Zhi

2019, 30(5):  1625-1632.  doi:10.13287/j.1001-9332.201905.033

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Understanding changes in vegetation productivity and carbon use efficiency and their responses to climate change is significant to accurately assess and predict regional carbon budget in Northeast forest area, a region being an important carbon sink and sensitive to global change. Based on MODIS monitoring data and vegetation type distribution data, I analyzed the spatiotemporal varia-tions of ecosystem productivity (net primary productivity (NPP), gross primary productivity (GPP)) and carbon use efficiency (NPP/GPP) of Northeast forest from 2000 to 2015. Results showed that the average NPP and GPP were 346.4 and 773 g C·m^-2·a^-1, respectively, and the average NPP/GPP was 0.45 during 2000 and 2015. NPP and GPP of different forest types were following the order: coniferous and broad-leaved mixed forests > deciduous broad-leaved forests > coniferous forests, while the difference in NPP/GPP was not significant among different forest types. NPP and GPP were high in Southeast part and low in Northwest part. From 2000 to 2015, the NPP, GPP and NPP/GPP of Northeast forest showed a fluctuating increase, suggesting the carbon sequestration capacity was gradually enhanced. However, the trends and rates of NPP, GPP and NPP/GPP showed spatial variation. NPP, GPP and NPP/GPP increased significantly in the southern part of the Daxing’anling while decreased significantly in the northern part of the Daxing’anling, and showed a weak increasing trend in the rest of Northeast forest. The increase of annual precipitation was the main factor driving the fluctuating increase of NPP, GPP and NPP/GPP in Northeast forest.

Ecological vulnerability assessment on Changbai Mountain National Nature Reserve and its surrounding areas, Northeast China.

ZHU Qi, ZHOU Wang-ming, JIA Xiang, ZHOU Li, YU Da-pao, DAI Li-min

2019, 30(5):  1633-1641.  doi:10.13287/j.1001-9332.201905.030

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Exploring the ecological vulnerability of nature reserve and its surrounding area is essential to the maintenance of regional ecological security and sustainability of human development, especially under the stress of global change and human activities. Based on the integration of "sensitivity-resilience-pressure" conceptual model and spatial principal component analysis (SPCA), we analyzed the ecological vulnerability of Changbai Mountain National Nature Reserve and its surrounding 30 km buffer in 2005 and 2015. The main driving factors were further analyzed. The results showed that the ecological vulnerability of Changbai Mountain Nature Reserve was mainly potential, slight, and light levels in 2005 and 2015, indicating the ecological vulnerability inside and outside the reserve was in a good condition. For the whole region, the ecological vulnerability showed a slight downward trend from 2005 to 2015. The degradation area inside and outside the reserve were 254 and 967 km², respectively, with the contribution rate to the increase of overall vulnerability being 30.8% and 69.2%, respectively. The changes in ecological vulnerability inside the reserve were mainly related to the changes in net primary production (NPP), vegetation coverage, and the nearest distance to the road, whereas it was mainly related to the changes in NPP, vegetation coverage and gross domestic product (GDP) density outside the reserve.

Spatial distribution of forest carbon storage in Maoershan region, Northeast China based on geographically weighted regression kriging model.

SUN Yu-sen, WANG Wei-fang, LI Guo-chun

2019, 30(5):  1642-1650.  doi:10.13287/j.1001-9332.201905.024

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Forest carbon storage has important impacts on climate change. The previous models do not take into consideration of the inherent spatial correlation structure of residual and non-stationary of forest carbon storage which limits the prediction accuracy. Based on ETM+ remotely sensed imagery and 193 fixed plots of Maoershan Experimental Forest Farm of Northeast Forestry University, we established the geographically weighted regression kriging (GWRK) model between forest carbon storage and extracted factors from remotely sensed imagery and topographic factors. The prediction accuracy of GWRK, ordinary least square (OLS) model and geographically weighted regression (GWR) were compared. The results showed that the mean absolute error (MAE) and root mean square error (RMSE) of GWRK were lower than those of OLS and GWR models, while the mean error (ME) of GWRK model was lower than that of GWR model and was close to that of OLS model. The prediction accuracy of GWRK model was 83.2%, which was 6% and 10% higher than that of OLS model (73.7%) and GWR model (77.3%). Therefore, the GWRK model was more effective in estimating forest carbon storage than the others. The mean value of forest carbon storage predicted by GWRK model was 70.31 t·hm^-2. The relatively high values presented in high altitude area, indicating that altitude had a great impact on forest carbon storage.

Effects of thinning on soil carbon and nitrogen fractions in a Larix olgensis plantation.

ZHOU Tao, WANG Chuan-kuan, ZHOU Zheng-hu, SUN Zhi-hu

2019, 30(5):  1651-1658.  doi:10.13287/j.1001-9332.201905.020

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Thinning, an important forest management strategy, can alter forest structure and stability, and consequently affect ecosystem biogeochemical cycles. The effects of thinning on soil carbon and nitrogen is far from conclusive especially due to the lack of long-term experiments. Here, we investigated soil carbon and nitrogen in Larix olgensis plantations in Mengjiagang Forest Farm, Heilongjiang Province, with four thinning treatments (i.e., 4 times low-intensity thinning, LT4; 3 times medium-intensity thinning, MT3; 2 times high-intensity thinning, HT2; and un-thinned control). The effects of thinning on soil total organic carbon and total nitrogen were examined from the perspective of the composition of labile and recalcitrant pools (labile carbon or nitrogen pool I; labile carbon or nitrogen pool II; and recalcitrant carbon or nitrogen pool) by an acid hydrolysis approach. The results showed that thinning significantly increased soil total organic carbon and nitrogen by 48.7%-50.3% and 28.9%-42.7%, respectively. The carbon and nitrogen contents in all the labile I, labile II, and recalcitrant pools were increased by thinning, with the magnitudes varying across different pools and thinning types. LT4, MT3, and HT2 improved the recalcitrant carbon by 71%, 69% and 75%, respectively, which was significantly higher than the increment of two labile carbon pools. In addition, the percentage of recalcitrant carbon in total organic carbon was increased by thinning. LT4 significantly increased microbial biomass and microbial quotient, but no significant change was found in MT3 and HT2 treatments. Overall, our results indicated that thinning might increase the input of soil recalcitrant carbon components such as suberin and lignin by producing more coarse woody residues, thus leading to decline of organic matter decomposition and ultimately enhancement of soil organic carbon.

Effects of latitudinal transplanting on temperature sensitivity of leaf dark respiration for Larix gmelinii.

WAN Li-na, WANG Chuan-kuan, QUAN Xian-kui

2019, 30(5):  1659-1666.  doi:10.13287/j.1001-9332.201905.032

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Exploring the temperature sensitivity of leaf dark respiration is of significance for understanding forest carbon cycling and its response to climate change. However, its intra-specific variability and seasonality are not clear yet. In this study, we measured the temperature sensitivity coefficient (Q₁₀) of leaf dark respiration for Dahurian larch (Larix gmelinii) that were transplanted from four latitudinal sites (i.e., Tahe, Songling, Heihe, and Dailing) in a common garden. Our specific aims were to explore the seasonal dynamics of Q₁₀ and compare differences in Q₁₀ among the indivi-duals from the four latitudinal sites. The results showed that the Q₁₀ for the four sites exhibited similar seasonal trend, with the maximum Q₁₀ in the middle growing season. The inter-site difference in Q₁₀ was significant, ranging from (1.48±0.01) to (2.15±0.03). Furthermore, the inter-site difference showed the same pattern across the whole growing season, i.e., the warmer and lower latitudinal sites, the higher Q₁₀. The Q₁₀ was significantly and positively correlated with foliar nitrogen concentration and soluble sugar concentration, and mean annual temperature and mean annual precipitation in the transplanting sites. These findings suggested that the inter-site variation in Q₁₀ and its seasonality could be mainly attributed to the foliar nutrient concentration and adaptation of trees to the climatic conditions of the transplanting sites, which should be considered in modeling and predicting responses of forest carbon cycling to climate change.

Vertical variation and model construction of area and dry mass for a single leaf from six broadleaved trees in mixed broadleaved-Korean pine forests.

JI Meng, WANG Yan-jun, JIN Guang-ze, LIU Zhi-li

2019, 30(5):  1667-1678.  doi:10.13287/j.1001-9332.201905.022

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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.

Variation of the growth, fruiting and resistance to disease and insect of the half-sib families of Pinus koraiensis superior trees.

WANG Fang, WANG Yuan-xing, WANG Cheng-lu, ZHANG Wei-na, LIU Wei-sheng, LU Zhi-min, YANG Yu-chun

2019, 30(5):  1679-1686.  doi:10.13287/j.1001-9332.201905.016

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We investigated the growth traits (tree height, diameter at the breast, crown diameter), fruiting traits (total number of cones in 7 consecutive fruiting years) and resistance to disease and insect of 551 half-sib families of Pinus koraiensis superior trees in 29-year-old in Hongwei seed orchard of Lushuihe, Jilin Province, with the method of multi-trait comprehensive evaluation and combining with six traits. The results showed that all the traits were significantly different among different families or blocks. Phenotypic variation coefficient of different traits ranged from 13.9% to 61.0%. The extremely significant difference and high variation coefficients were beneficial for elite families evaluation and selection. The family heritability of volume, seed yield and resistance to disease and insect (the values were 0.47, 0.52, 0.48, respectively) were higher than single plant heritability (the values were 0.37, 0.07, 0.10, respectively). There was a extremely significant positive correlation between growth traits, fruiting traits and resistance to disease and insect. 28 elite families were selected with a selection rate of 5%, with the genetic gains of volume, seed yield and resistance to disease and insect being 16.8%, 71.4% and 0.5%, respectively. Seven elite individuals were selected from the elite families with a selection rate of 2%, with the genetic gains of volume, seed yield and resistance to disease and insect being 66.8%, 80.9% and 0.7%, respectively. These elite families and individual plants showed obvious advantages, which could guide the thinning of clonal seed orchards and provide breeding materials for the construction of high-generation seed orchards.

Variation of leaf area index estimation in forests based on remote sensing images of different spatial scales.

LIU Ting, CHEN Chen, FAN Wen-yi, MAO Xue-gang, YU Ying

2019, 30(5):  1687-1698.  doi:10.13287/j.1001-9332.201905.014

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There are several important issues in quantitative remote sensing and product authenticity testing, including how well do the ground measurement points represent the remote sensing pixels, how to obtain the relative truth value of pixels, and how much spatial resolution can truly reflect fore-st leaf area index (LAI). In this study, the measured space scope of two plant canopy analyzers [LAI-2200 and tracing radiation and architecture of canopies (TRAC)] were calculated, which were combined with remote sensing images with three different spatial resolutions: GF-2 with 4.1 m spatial resolution, the Sentinel-2 with 10 m spatial resolution, and Landsat-8 OLI with 30 m spatial resolution, to get the relative true value of pixel at each scale. Under the condition of keeping the real observed area consistent with that obtained by remote sensing, the effects of different spatial resolution images for estimating forest LAI were compared and analyzed based on the unary exponential and multiple regression statistical models. Moreover, the optimal statistical models of the three images were tested on 30 m and 100 m scales and the spatial representation of dataset were evaluated, to find the most suitable scale for the description of forest LAI in the study area. The results showed that high resolution did not necessarily fully reflect LAI of forests. The statistical model based on three kinds of resolution images could well estimate forest LAI. Among the three models, the model based on the Sentinel-2 image had the highest accuracy, and the one based on the GF-2 images had the lowest. The test results at 30 and 100 m scales indicated that the forest LAI was overestimated by the GF-2 inversion model, and underestimated by the Landsat-8 inversion model. The statistical model based on Sentinel-2 could well estimated forest LAI in the study area.

Effects of climate change, fire and silvicultural management on ecological resilience of typical cold-temperate forests in China.

LUO Xu, LIANG Yu, HE Hong-shi, HUANG Chao, ZHANG Qing-long

2019, 30(5):  1699-1712.  doi:10.13287/j.1001-9332.201905.011

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Ecological resilience is characterized by the recovery capacity of forest ecosystem from a status affected by external disturbance to a stable status, which is one of the important targets for sustainable development of forests. Ecological resilience is sensitive to external factors, such as climate change, forest fire, and silvicutural management at large scales. Understanding the effects of those factors on ecological resilience is important for forest ecosystem management. In this study, we calculated ecological resilience with indicators including forest structure, composition and function. We used a landscape model LANDIS PRO to evaluate the effects of climate change, climate-induced fire, and silvicultural management on ecological resilience in boreal forests. We also evaluated whether the current thinning treatment could be implemented under the scenarios of climate change. The results showed that the initialized stand density and basal area from the year 2000 could represent the real forest landscape in year 2000, with no significant difference between the simulated landscape and the forest inventory data in the year 2010 at landscape scale. The results of simulated fire disturbance were consistent with the results from the field inventories in burned areas. The fire module parameters set adequately represented the current fire regimes in model simulation. The ecological resilience could increase by 15.7%-40.8% at landscape scale when fire intensity increased by 30%, whereas the ecological resilience decreased by 4.4%-24.6% when fire intensity increased by 200%. At the short and medium term, the effects of increased fire on forest ecological resilience were greater than that of climate change. Compared to the current base scenario, forest ecological resilience under B1 climate with fire intensity increased by 30% scenario and A2 climate with fire intensity increased by 200% scenario fluctuated in the ranges of -15.9%-38.9% and -60.4%-34.8% in the whole simulation period at landscape scale. Compared to no harvesting scenario, the current thinning strategy would decrease the ecological resilience at landscape scale under both B1 and A2 scenarios in all simulated periods. Under the scenario of B1 climate with 30% increases of fire intensity, no silvicultural management would be needed in the whole simulation period at landscape scale, whereas medium and high intensity of silvicultural management were suggested under the scenario of A2 climate with 200% increase of fire intensity.

Effects of harvest on greenhouse gas emissions from forested swamp during non-growing season in Xiaoxing’an Mountains of China.

HAO Li, MU Chang-cheng, CHANG Yi-hui, SHEN Zhong-qi, HAN Li-dong, JIANG Ning, PENG Wen-hong

2019, 30(5):  1713-1725.  doi:10.13287/j.1001-9332.201905.036

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Soil greenhouse gas emission during non-growing season plays an important role in ecosystem carbon and nitrogen cycling in mid and high latitude regions. However, the effects of harvest on greenhouse gas emission during non-growing remain unclear. We measured the fluxes of CO₂, CH₄ and N₂O and environmental factors (soil temperature, moisture, soil organic carbon and total nitrogen etc.) during non-growing season from four kinds of forested swamps (Alnus sibirica swamp, Betula platyphylla swamp, Larix gmelinii-Carex schmidti swamp, L. gmelinii-moss swamp) under different harvest disturbances for 10 years, including control (no cutting), 45% selective cutting, clear cutting, by using static chamber technique and gas chromatography in Xiaoxing’an Mountains, Northeast China. The aim of this study was to reveal the effects of harvest on greenhouse gas emission from temperate forested swamp during non-growing season and the main controlling factors. The results showed that the average fluxes of CO₂, CH₄ and N₂O from four kinds of swamps distributed in 53.08-81.31 mg·m^-2·h^-1, 0.09-3.07 mg·m^-2·h^-1 and 4.07-8.83 μg·m^-2·h^-1, respectively. Clear cutting significantly increased the fluxes of CO₂, CH₄, and N₂O from A. sibirica swamp and L. gmelinii-moss swamp. Selective cutting significantly increased CO₂ fluxes from B. platyphylla swamp and L. gmelinii-moss swamp and decreased CO₂ flux from A. sibirica swamp. Selective cutting significantly decreased CH₄ fluxes from all the four forested swamps and N₂O flux from Larix gmelinii-Carex schmidti swamp. The CO₂ fluxes from natural forested swamps were strongly influenced by soil temperature, soil organic carbon and C/N. CH₄ fluxes were influenced by soil temperature, soil organic carbon. N₂O fluxes were affected by air temperature and soil pH. Harvesting increased the correlation between soil CO₂ flux and air temperature, soil moisture and snow depth, the correlation between soil CH₄ flux and air temperature, soil moisture and C/N, as well as the correlation between soil N₂O flux and soil total nitrogen and C/N. The annual cumulative contribution of CO₂, CH₄ and N₂O emission from natural forested swamp during non-growing season were 33.2%-46.5%, 6.3%-9.1% and 61.5%-68.3%, respectively. The clear cutting increased the annual cumulative contribution of CO₂ from B. platyphylla swamp and L. gmelinii-moss swamp and that of N₂O from other swamps except L. gmelinii-moss swamp. The selective cutting increased the annual cumulative contribution of CO₂, CH₄ and N₂O from L. gmelinii-C. schmidti swamp and L. gmelinii-moss swamp, but decreased that from B. platyphylla swamp. The annual cumulative contributions of N₂O and CO₂ during non-growing season were relatively high from temperate natural forested swamps, and clear cutting further increased their contribution, while the selective cutting just increased that of CH₄ during non-growing season.

Soil respiration and its temperature sensitivity among different vegetation types in Beijing mountain area, China.

ZHENG Peng-fei, YU Xin-xiao, JIA Guo-dong, LI Hong-Juan, WANG Yu-song, ZHU Xu-hui

2019, 30(5):  1726-1734.  doi:10.13287/j.1001-9332.201905.038

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As an important component of terrestrial ecosystem carbon cycle, soil respiration is a hot topic in the studies of carbon cycle. The temperature sensitivity (Q₁₀) of soil respiration is a critical index to estimate the effects of global warming on soil respiration. Understanding Q₁₀ of different vegetation types is of important significance for assessing the carbon budget of forest ecosystems. We examined soil respiration and its temperature sensitivity in three typical forests (Pinus tabuliformis, Platycladus orientalis, and Quercus variabilis) in the Beijing mountainous area by measuring the soil physical and chemical properties, soil temperature, soil moisture, and soil respiration rate (R_s) during the growing season. The results showed that R_s of three typical vegetation types showed a similar trend with changes of soil temperature and humidity, which showed a unimodal pattern, with minimum value (0.45 μmol·m^-2·s^-1) in early April and maximum value (3.95 μmol·m^-2·s^-1) in early July. There were significant differences in R_s and Q₁₀ values among the three vegetation types. Soil temperature and humidity were the important factors affecting soil respiration, together they could explain the seasonal variation of soil respiration rate from 48.1% to 56.7%. The range of Q₁₀ value was between 2.05 and 3.19. There was a significant negative correlation between soil organic carbon content and Q₁₀ under each vegetation type (R²>0.9). Vegetation type, elevation, and soil organic carbon content were important drivers for the variation of Q₁₀.

Effects of nitrogen addition on tree root traits.

LIU Rui-xue, WU Hong-jin, HUANG Guo-zhu, ZHAO Chuan-yan, LI Wei-bin

2019, 30(5):  1735-1742.  doi:10.13287/j.1001-9332.201905.005

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Atmospheric nitrogen deposition has complex effects on individual plants and terrestrial ecosystems. We synthesized results from 39 published papers (16 papers in English and 23 papers in Chinese) and conducted a meta-analysis to evaluate the general responses of tree root traits to nitrogen addition, and further analyzed the difference of N-induced results between English papers and Chinese papers. Our results showed that N addition significantly increased fine root diameter (+6.7%), fine root N content (+8.9%), and root respiration rate (+17.5%), but did not affect fine root biomass, fine root length, specific root length, fine root C content, and fine root C:N ratio. Different climatic zone and fertilizer types had different effects on the experimental results. In addition, experimental results published in English papers were generally more significant than those in Chinese papers. We summarized the general effects of N addition on tree root systems, and further analyzed the mechanisms underlying the effects of N enrichment on forest ecosystem carbon cycle.

Spatiotemporal dynamic simulation on aboveground carbon storage of bamboo forest and its influence factors in Zhejiang Province, China.

LIU Teng-yan, MAO Fang-jie, LI Xue-jian, XING Lu-qi, DONG Luo-fan, ZHENG Jun-long, ZHANG Meng, DU Hua-qiang

2019, 30(5):  1743-1753.  doi:10.13287/j.1001-9332.201905.035

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Bamboo forests have an efficient carbon sequestration capacity and play an important role in responding to global climate change. However, the current estimation of bamboo carbon storage has some errors, leading to uncertainty in the spatiotemporal pattern of bamboo forest carbon storage. This study simulated aboveground carbon storage of Zhejiang Province, China, during 1984-2014 based on the combination of an improved BIOME-BGC (biogeochemical cycles) model and remote sensing data, with the accuracy being verified with forest resource inventory data. The spatio-temporal distribution and environmental factors of aboveground carbon storage were analyzed. The results showed that the simulated carbon storage was accurate, with average correlation coefficient (r), root mean square error (RMSE) and relative bias (rBIAS) being 0.75, 7.24 Mg C·hm^-2 and -2.57 Mg C·hm^-2, respectively. Generally, the aboveground carbon storage of bamboo forests in the whole province tended to increase from 1984 to 2014, the range of aboveground carbon density was 13.10-17.14 Mg C·hm^-2, and that of the total aboveground carbon storage was between 9.94-17.19 Tg C. The high aboveground carbon storage of bamboo was mainly distributed in developed bamboo industry areas, such as Anji, Lin’an, and Longyou. The change of aboveground carbon storage in bamboo forest was significantly correlated with temperature, precipitation, radiation, CO₂ concentration and nitrogen deposition, with higher partial correlation coefficients between precipitation and temperature and carbon storage.

Effects of nitrogen deposition on the concentration and spectral characteristics of dissolved organic matter in soil in Moso bamboo plantations.

CHENG Lei, LIN Kai-miao, ZHOU Jia-cong, ZHANG Qiu-fang, ZENG Xiao-min, JI Yu-huang, ZHENG Yong, XU Jian-guo, CHEN Yueh-min

2019, 30(5):  1754-1762.  doi:10.13287/j.1001-9332.201905.034

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The subtropical zone in China is one of the regions most affected by nitrogen deposition. Soil dissolved organic matter (DOM) is considered to be an important indicator of soil organic matter. Nitrogen deposition may alter the quality and quantity of soil DOM by changing soil microbial activity. In this study, we explored the effects of nitrogen addition on soil DOM content, its spectral characteristics and microbial extraceller enzyme activity in the Moso bamboo plantations by setting control (CT), low-nitrogen (LN), and high-nitrogen (HN) addition levels for three-year nitrogen addition. The results showed that there was no significant change in soil pH, dissolved organic carbon, dissolved organic nitrogen, and aroma index following nitrogen addition, while the humification index increased significantly, microbial enzyme activities increased first and then decreased with the increases of nitrogen addition. Fourier transform infrared spectroscopy results showed that soil DOM had similar absorption peaks in seven regions, and that the absorption peaks of 1000 to 1260 cm^-1 were the strongest, indicating an enhanced amount of polysaccharides, alcohols, carboxyl acids, and esters after nitrogen addition. The results of three-dimensional fluorescence spectroscopy showed that soil DOM structure significantly changed following nitrogen addition, with a decrease in low-molecular substances such as protein-like substances and microbial metabolites and a significant increase in high-molecular substances such as humus-like substances. In general, nitrogen addition made soil nitrogen compatible with microbial requirements. Microorganisms decompose substances that were easily degraded in DOM. The structure of soil DOM was more complex after nitrogen addition. Therefore, short-term nitrogen deposition might be conducive to preserving soil fertility.

Quantitative evaluation for separation of water-soluble and water-insoluble particulate matter on leaf surface of tree species: Taking five tree species as examples.

LIU Jin-qiang, CAO Zhi-guo, GUO Ze-min, DUAN Jie, KANG Jia, LIU Huan-huan, YAN Guang-xuan, XI Ben-ye

2019, 30(5):  1763-1771.  doi:10.13287/j.1001-9332.201905.031

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To accurately and quantitatively evaluate the mass and particle size distribution of water-soluble and water-insoluble particulate matters (PM) on the surface of tree leaves, which would help to improve the accuracy of quantitative assessment of the retention ability of urban trees to atmospheric particles, we collected leaf samples from three broadleaved tree species [Ginkgo (Ginkgo biloba), Chinese scholar tree (Sophora japonica) and weeping willow (Salix babylonica)] and two conifer species [Chinese pine (Pinus tabuliformis) and China savin (Sabina chinensis)] 14 d after the rain (rainfall>15 mm). The PMs retained on leaves were collected by a succeeding procedure of washing + brushing (WC+BC) and ultrasonic cleaning (UC). Then, the extracts at each step were divided into water-soluble and water-insoluble PMs through centrifuge. The mass of water-soluble and water-insoluble particles were dry weighted. Then, the water-soluble and water-insoluble particles were dissolved by anhydrous ethanol and deionized water to measure the particle size distribution. The mass of water-soluble and water-insoluble particles with different particle sizes was calculated. Results showed that the mass (proportion) of water-soluble PMs retained on leaf surfaces of broad-leaved and conifer species were 480.61 (52.3%) and 438.91 (47.7%) mg·m^-2, respectively, while that for water-insoluble PM_s were 97.93 (12.0%) and 715.84 (88.0%) mg·m^-2, respectively. The particle size distribution of water-soluble particles on the leaves of the five tree species showed the unimodal curve with mean size of 40.36 μm. Water-insoluble particles on leaves showed multimodal distribution, with mean size of 105.65 μm. S. japonica and G. biloba had higher PM retention ability in regions suffering with more water-soluble PM pollution, while S. chinensis had higher retention ability to water-insoluble PMs.

Measuring and calculating methods of plant mesophyll conductance: A review.

ZHU Kai, YUAN Feng-hui, GUAN De-xin, WU Jia-bing, WANG An-zhi

2019, 30(5):  1772-1782.  doi:10.13287/j.1001-9332.201905.002

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Mesophyll conductance (g_m) refers to the diffusion capacity of CO₂ inside mesophyll cells, which is the reciprocal of resistance of mesophyll cells. In the early stage of photosynthesis research, mesophyll diffusion resistance to CO₂ was usually assumed to be zero, namely the g_m was infinite. In recent studies, however, the g_m was found to be limited and changed with external environments. As g_m directly determines CO₂ diffusion and affects leaf photosynthetic efficiency, it is of great significance to mechanestic research of photosynthesis. Presently, simultaneous chlorophyll fluorescence and gas exchange, the curve-fitting and instantaneous carbon isotope (¹³CO₂) discrimination are commonly used to estimate g_m, but few literature have been introduced on those methods in China. Therefore, it is particularly necessary to elaborate the principles and processes of these methods and to compare their advantages and disadvantages. We synthesized the relevant literature, and introduced the three methods in detail from the aspects of principle, derivation process and advantages and disadvantages, aiming to provide a methodological basis to promote the research on g_m in China. The curve-fitting method was easy to understand and operate. Its fitting model varied with the status of photosynthesis, which is needed to be divided strictly by researchers. Consequently, it was not conducive to be widely used. Although the instantaneous carbon isotope (¹³CO₂) discrimination method improved the accuracy of results, it was complex in measurement and strict in operation. Furthermore, it was less sensitive to test errors with low reliability. Compared with the above two methods, simultaneous chlorophyll fluorescence and gas exchange was more operable and reliable, and was more conducive to the observation and analysis for large samples with multi-processing and multi-repetition. In addition, the use of chlorophyll fluorescence technology not only simplified the test procedures, but also reduced the accidental errors, making the results more scientific. Chlorophyll fluorescence technology also provided saturated pulse activation energy to maximize leaf photosynthetic potential. But this method also had many problems, for instance, to improve the accuracy of chlorophyll fluorescence parameters, a lower gas flow rate was needed, which would increase the risk of gas diffusion and leakage. Thus, this method had a high requirement for a reasonable gas flow rate. In general, simultaneous chlorophyll fluorescence and gas exchange method was most widely used in the actual determination of plant g_m.

Natural science research in Changbai Mountain during 1956-2018:A review.

LIU Ya-ge, ZHANG Mao-liang, GUAN De-xin, SONG Xiu-fang, YUAN Feng-hui, WU Jia-bing, WANG An-zhi

2019, 30(5):  1783-1796.  doi:10.13287/j.1001-9332.201905.003

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We synthesized the scientific research carried out in Changbai Mountain from 1956 to 2018 by mapping knowledge domains and bibliometrics based on the literature from international database (WOS) and domestic databases (CNKI and CSCD). The results showed that natural science research in Changbai Mountain underwent three stages during 1956-2018, including embryo stage, growing stage, and rapid development stage. The natural research in Changbai Mountain could be divided into five fields, i.e., forest and ecological science, volcano and geology science, environmental change science, resource sciences and utilization, animal and microbial science, with a total of 20 main research directions. Since 2000, forest and ecological science, volcano and geological science, environmental change science dominated the natural science research in Changbai Mountain. The researches in recent 20 years mainly concentrated on the following seven disciplines: community ecology, forest management, soil ecology, ecosystem ecology, eco-climatology, forest responses to environmental change, and volcanic geology. International researches showed a trend of strong integration of different disciplines. We forecast that the natural science research in the Changbai Mountain would deepen its research in the next decade. Moreover, other fields such as old-growth forest and large-scale ecosystem carbon processes, forest-altitude-climate change, soil fauna and microorganisms, forest management and human activities, biodiversity, volcanic origin and eruption history, volcanic eruption dynamics and volcanic monitoring will emerge as the new research focus. Scale polarization, elements diversification, discipline crossing, and research deepening would be the future trend of natural science research in Changbai Mountain.