Research advance in effects of solar radiation on litter decomposition in terrestrial ecosystems.

Litter decomposition significantly influences the carbon (C) dynamics of terrestrial ecosystems. Solar radiation is not only essential for photosynthetic C fixation and primary productivity, but also can directly or indirectly promote litter decomposition through photodegradation. Recently, photodegradation has been identified as a key factor driving litter decomposition and potentially impacts terrestrial C cycle.

[Effects of canopy spectral composition on growth and photosynthetic fluorescence characteristics of and seedlings].

We investigated the responses of leaf and individual traits, growth, and fluorescence characteristics of seedlings of two dominant species of broad-leaved Korean pine forest in Changbai Mountain, ., and , to five spectrum-attenuation treatments. Results showed that the architecture and growth of and seedlings were mainly regulated by ultraviolet B (UV-B) radiation and blue light.

Accounting of gross ecosystem product in Fuzhou City,China.

Carrying out the accounting of ecological system gross ecosystem product (GEP) is a necessary measure to promote the construction of ecological civilization system and an important measure for the integration of ecological benefits into the economic and social development evaluation system. Taking Fuzhou City as the object, we constructed an ecosystem value accounting system with the characteristics of "mountain, sea, and city" to calculate the GEP of Fuzhou City in 2015 and 2018, and compared them from the perspective of temporal and spatial changes. The results showed that the GEP of Fuzhou in 2015 and 2018 was 920.

Response of photosynthetic characteristics and non-structural carbohydrate accumulation of seedlings to drought stress.

We explored the effects of drought stress on photosynthetic characteristics and non-structural carbohydrate (NSC) accumulation of the timberline tree species in Changbai Mountain with a drought control experiment. The results showed that drought significantly reduced the net photosynthetic rate and stomatal conductance, but increased water use efficiency (WUE) of seedlings. Drought dramatically improved the contents of soluble sugar and total NSC in leaves, barks, stems, and roots of seedlings, but significantly reduced their starch content.

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

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.

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

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.

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

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), low N (N, 25 kg·hm), and high N (N, 50 kg·hm), with N being added as NHNO.

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

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.

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

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.

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

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.

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

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-hm plots, i.

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

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.

[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.].

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.

[Soil organic carbon density and its influencing factors of major forest types in the forest region of Northeast China].

The five main forest types, i. e. larch forest, birch forest, coniferous mixed forest, broad-leaved mixed forest, and coniferous and broad-leaved mixed forest, with varied age classes (young, mid-aged, pre-mature, and over mature) were selected to investigate the variation of soil organic carbon density in the forest region of Northeast China.

[Soil organic carbon storage in different aged Larix gmelinii plantations in Great Xing' an Mountains of Northeast China].

A sampling plot investigation was conducted to study the soil organic carbon (SOC) storage in 0-40 cm layer in 10-, 15-, 26- and 61 years old Larix gmelinii plantations in Great Xing' an Mountains of Northeast China as well as the temporal variation pattern of the SOC source/sink during the plantation management after the clear cutting of primary L. gmelinii forest. With the increasing age of the plantations, the SOC storage increased after an initial decrease, and the inflection point was at a stand age between 15- and 26-years old.

[Effects of altitudinal gradient on water use efficiency of Betula ermanii on the northern slope of Changbai Mountains, northeast China].

Taking Betula ermanii forests distributed at the altitudes 1800-2050 m on the northern slope of Changbai Mountains as test objects, and using leaf carbon isotope content (813 C) as an indicator of B. ermanii water use efficiency (WUE), this paper studied the effects of altitudinal gradient on the WUE of B. ermanji forests in the area.

[Research progress in water use efficiency of plants under global climate change].

Global climate change is one of the most concerned environmental problems in the world since the 1980s, giving significant effects on the plant productivity and the water transport and use patterns. These effects would be reflected in the water use efficiency (WUE) of individual plants, communities, and ecosystems, and ultimately, in the vegetation distribution pattern, species composition, and ecosystem structure. To study the WUE of plants would help to the understanding and forecasting of the responses of terrestrial vegetation to global climate change, and to the adoption of adaptive strategies.

[Dynamics of initial decomposition of Calamagrostis angustifolia litter in Sanjiang Plain of China].

A 28-day leaching-decomposition experiment was conducted to study the effects of microbial activity and leaching on the initial decomposition of Calamagrostis angustifolia litters taken from the boggy meadow and meadow in Sanjiang Plain of China. The results showed that the mass loss of the litters at their initial decomposition stage accounted for 59% and 22% of yearly mass loss, respectively, and the remaining dry mass decreased significantly after 28-day decomposition. By the end of the experiment, the N content in the litters decreased by 32.

[Phosphorus fractions under different land uses in Sanjiang plain].

Five land-uses type (soybean-filed, rice-field, abandoned cultivation, artificial forest, natural wetland) were obtained before planting and soil P fractions were determined by a modified Hedley fraction method. The result showed that the content of total P (TP) in natural wetland was higher than other soil. While the proportion of total inorganic P (TPi) in TP of farm land soil was higher than that of wetland.

[Nitrification-denitrification and N2O emission of typical Calamagrostis angustifolia wetland soils in Sanjiang plain].

With intact soil core and by using acetylene inhibition method, this paper measured the N2O emission and denitrification rates of typical Calamagrostis angustifolia wetland soils in Sanjiang Plain, analyzed their relationships with environmental factors, and estimated the total amounts of N2O emission and denitrification loss. The results showed that meadow marsh soil and humus marsh soil had a similar change range of N2O emission rate (0.020-0.

[Phytoavailable lead in rhizosphere of lettuce].

A greenhouse experiment was performed to investigate the influence of pH TOC, and fractionation of Pb on phytoavailability of Pb in the rhizosphere of lettuce. And the Low molecular-weight organic acids (LMWOAs) were used to evaluate the phytoavailability of soil Pb to lettuce. The results show that the pH is lower in the rhizosphere compared to the bulk soil, and the rhizosphere becomes more acidic with increasing Pb (NO3)2 applied.