Forest microclimate is the local environment generated through the interaction between regional climate and forest structure. Studies on forest microclimate not only have theoretical significances in ecology but also practical meanings in forest management practices and wood production. Radiation budget and energy balance is the basis for microclimate. Few studies have performed the radiatoin budget and energy balance analysis at regional scale. Here, we focused at this for the East Asia.

A total of 17 forest sites in the East Asia across biomes were used in this study. Measurements on solar radiation, long-wave radiation, net radiation, sensible heat flux, latent heat flux, and soil heat flux were compiled in the context of radiation and energy conservation. The annual variations of radiation and energy components were analyzed by site. Mean annual radiation and energy were related to latitude. The radiation and energy conservation equations were established for each forest biome by the multi-site block averages.

Forest radiation properties (i.e. solar radiation, net radiation, albedo) showed a linear trend with latitude among the sites. For example, the solar radiation and latitude relationship is: y = 6205 - 42.15x (p < 0.01), indicating that solar radiation decreases with latitude at a rate of 42 MJ per degree with a theoretical maximum of 6205 MJ. A more significant relationship was found between net radiation and latitude: y = 4340 - 45.60x (r = -0.89, p < 0.0001). The radiation and energy budgets of boreal, temperate, subtropical and tropical forest were established. Evapotranspiration fraction (EF) was highly correlated with precipitation (P) as: EF = 0.7098(1 - exp(-0.0026P)) (R² = 0.7451, p < 0.0001). Subtropical forest showed a unique pattern in this cross-biome analysis but needs further studies in the future.

The objective of this study was to characterize the ecosystem carbon sequestration during natural restoration process of karst forest vegetation.

We adopted the “space for time” approach to examine the pattern of carbon sequestration in karst forest ecosystems along the natural restoration process. Forest vegetation types representing six typical successional stages were selected and investigated, which include herb stage, herb to shrub stage, shrub stage, shrub to arbor stage, arbor stage, and climax stage. Twenty-four plots of 30 m × 30 m were established on sites of the six forest types, and samples of plants, litter and soil were collected in each plot.

The total vegetation biomass increased from 7.97 to 166.83 t·hm^-2 with advancement of restoration stages, corresponding to the trend of changes in biomass for the arbor layer (from 41.77 to 164.59 t·hm^-2), but with declining biomass for the herb layer (from 8.45 t·hm^-2 at the herb to shrub stage to 0.68 t·hm^-2 at the climax stage) and the shrub layer (from 32.87 t·hm^-2 at the shrub stage to 1.56 t·hm^-2 at the climax stage). The ratio of above ground to belowground biomass in karst vegetation was relatively low (varying between 1.26 and 2.03), especially for the shrub layer (varying between 1.23 and 1.45). The weighted average carbon content increased from 36.76% to 48.74% with the process of restoration. In the process of the natural restoration, the carbon density in the arbor layer increased from 19.44 to 80.40 t·hm^-2, but decreased from 3.19 t·hm^-2 at the herb to shrub stage to 0.23 t·hm^-2 at the climax stage in the herb layer and from 15.13 t·hm^-2 at the shrub stage to 0.69 t·hm^-2 at the climax stage in the shrub layer. The overall carbon density showed an increasing trend from the early stages (herb and herb to shrub stages), through the middle stages (shrub and shrub to arbor stages), to the late stages (arbor and climax stages) at levels of ecosystems (from 15.72 to 99.37 t·hm^-2), vegetation (from 2.93 to 81.31 t·hm^-2), and soil (from 8.26 to 18.80 t·hm^-2), accompanied by a reduction in litter (from 4.97 to 1.53 t·hm^-2). It can be concluded that vegetation, especially the component of woody plants, has the greatest influence on ecosystem carbon stocks during the recovery progress of karst forests, with little effects of soils. Therefore, it is important to facilitate the recovery of vegetation for enhancing karst ecosystem carbon sink.

Carbon and water cycling are two key processes in circulation of materials and energy flow of sandy grassland ecosystem; recognition of changes in carbon and water cycling is important for understanding the responses of sandy grassland ecosystem structure and function to regional climate change and human activities. Our objectives were to determine the regulations of carbon sequestration and emission, and to examine the relationships of carbon and water fluxes with environmental factors.

Chamber method was used to measure carbon and water fluxes in grazed plots and fencing enclosures of different durations in a sandy grassland over a growing season in 2013.

(1) Variance analysis revealed that, during the observational period, the gross ecosystem productivity (GEP), ecosystem respiration (ER), and evapotranspiration (ET) were all in an order of: 17-year enclosure > 22-year enclosure > grazing, with significant differences (p < 0.05) among the treatments; the maximum values were 2.23, 1.65, and 1.94 times of the minimum values, respectively. (2) There was a significant linear and positive correlation between GEP and ET (p < 0.01); ET explained 58% to 60% of the variations in GEP. Water use efficiency (WUE) decreased from 2.85 μmol·nmol^-1 in the 22-year enclosure to 2.75 μmol·nmol^-1 in the 17-year enclosure, and to 2.10 μmol·nmol^-1 in grazed plots. (3) There were significant linear and positive correlations between GEP, ER and soil water content. Exponential model better fitted the responses of ecosystem respiration to soil temperature. The temperature sensibility coefficient Q₁₀ values of ER ranked in the order of 17-year enclosure (1.878) > 22-year enclosure (1.733) > grazing (1.477). In conclusion, enclosure enhanced the carbon and water cycling in degraded sandy grassland ecosystem. However, a 22-year enclosure is not beneficial to this process than 17-year enclosure, suggesting that proper enclosure is conductive to the recovery of degraded sandy grassland and effective to the use of sandy grassland resources.

The number of root forks and link length influence distribution patterns of plant roots. The trade-off between root forks and link length has an important meaning for comprehending ecological adaptation strategy of root architecture. Our objective was to study the relationship between root forks and link length of Melica przewalskyi population in response to slope aspects in the northwest of China.

The study site was located in a degraded alpine grassland on the northern slope of Qilian Mountains, Gansu Province, China. Survey and sampling were carried out in 80 plots that were set up along four aspect transects of a hill with 20 m distance between adjacent plots. A handheld GPS was used to record latitude, longitude and altitude of each plot. ArcGIS was used to set up digital elevation model (DEM) to extract the information of elevation, aspect, and slope for each plot. The traits of plant communities were investigated and three individual samplings of M. przewalskyi were collected randomly in each plot. The samples were cleaned and divided into different organs. The roots were scanned with the Win-RHIZO for measurements of root forks and link length in laboratory, and biomass of different organs was measured after being dried at 80 °C in an oven. The 240 plots were categorized into groups of north, east, west and south aspects of slopes, and the linear regression analysis was then used to examine the trade-off relationship between root forks and link length in different groups.

With a change of the aspect from north to east, west and south, the density, aboveground biomass, height and soil moisture content of the plant community displayed a pattern of steadily declining, while the density, height, root link length of M. przewalskyi increased, and the root forks decreased. The number of root forks was negatively correlated with the link length in all aspects, but the relationship varied along the aspect gradient (p < 0.05). There was a highly significant negative correlation (p < 0.01) between the root forks and link length on north slope and south slope, whereas less significant (p < 0.05) on the east slope and west slope, all indicating a trade-off relationship between the root forks and link length. Consequently, the patterns of resource allocation between root forks and link length in different slope habitats reflected the response and adaption of plant root functional traits to their biotic and abiotic environments and the investment balance mechanism for root architecture construction.

Multivariate regression tree (MRT) is a new statistical technique for plant community classification. Studies on advantages of MRT were still insufficient. Our objective was to compare the results of MRT with two-way indicator species analysis (TWINSPAN), which is widely used in recent years, and to provide suggestions for choosing an appropriate classification method.

We used both MRT and TWINSPAN to classify the forest communities in the southern part of Lüliang Mountain. The MRT analysis gave a tree with the splits based on additional environmental factors. The degree of consistency between the two classifications are compared through the coherence coefficient.

(1) MRT divided 41 forest quadrats into four formations: the Platycladus orientalis formation, Acer davidii formation, Quercus wutaishanica formation and Diospyros kaki formation. The types of the formations are consistent with the analysis results from TWINSPAN. (2) Based on the quadrats that compromise the formations, these two methodologies provided a relatively high consistency, with the coherence coefficient up to 80.5%. (3) Compared with the TWINSPAN, the MRT can be seen as a form of constrained classification analysis that can relate different aspects of species composition to environmental data, so the clusters defined by the MRT define community types of the ecotone in an objective manner not available in other techniques. Finally, the TWINSPAN is a very effective classification technique in plant ecology research. However, the MRT has advantage over the TWINSPAN in terms of classifying continuous or transitional quadrats.

Trait-based approaches are often widely used in ecological research to predict or explain the complex ecological processes at both individual and ecosystem levels. Leaf function with morphological and physiological traits can play important roles in plan growth, survival, reproduction in natural environments. The aim of this study is 1) to determine the differences of leaf traits between both the species and the functional groups in a swamp meadow; 2) to explore the relationship between different leaf morphological traits and physiological traits.

Gas exchanges of 51 species (in 14 families) were measured on six fully expand health leaves (from different individual plants) using a portable photosynthesis system in the field during the peak of growing season. The leaf morphological traits was measured based on 6 single leaves form different individuals, include the net photosynthesis rate (P_n), transpiration rate (T_r), specific leaf area (SLA), relative leaf water content (LWC), leaf area (LA) and the water use efficiency (WUE = P_n/T_r).

Result showed that there were significant interspecific differences in the investigated traits as described in above methods. Among the traits, the LWC (coefficient of variation, CV = 0.11) was ranged from 58.12% to 81.83%, 0.0088-0.0278 m²·g^-1 for the SLA (CV = 0.27), and 0.51 cm² to 100.90 cm² for the LA (CV = 1.73), while the range of 4.25-19.23 μmol CO₂·m^-2·s^-1, 2.89-12.81 mmol H₂O·m^-2·s^-1 and 0.56-3.76 μmol CO₂·mmol^-1 H₂O for P_n (CV = 0.33), T_r (CV = 0.33), and WUE (CV = 0.36), respectively. There were also significant differences between the functional groups (sedge, grass and forbs) for these traits. Forbs have larger LA and higher LWC than sedge and grass; Grass have higher WUE and SLA than those of others; while Sedge have higher P_n. Our result also showed there were high correlation between P_n and SLA, WUE and LWC, indicated the strong impacts of leaf morphology on the gas exchange physiology. The SLA was also related to gas exchange traits both among species and functional groups, while the LWC was only among species and LA among functional groups. In conclusion, significant differences in these functional traits among species suggest that these species could vary in resource use and growth form in their community ecosystem. Also the difference among the functional groups in these traits indicates the resource use of the community would be largely influenced by its species composition, especially the differences of functional groups. The research finding will help to better understanding of the ecosystem function in alpine swamp meadow with related management implication.

Mangrove forest is desirable for studying variations in wood structure along an ecological gradient because mangroves are subjected to considerable habitat changes apart from salt stress within a small area. To elucidate the adaptive capability of wood structures towards fluctuating environmental conditions, variations in wood structures were investigated in 18 individuals of Rhizophora stylosa representing 6 populations along a natural soil physicochemical gradient in the National Nature Reserve of Dongzhai Harbor, Hainan Province.

Soil physicochemical properties were determined at the sites of 18 sampling trees in six R. stylosa populations. The anatomical characteristics of the secondary xylem were studied in details in the 18 trees by means of light microscopy, laser scanning confocal microscopy, scanning electron microscopy and transmission electron microscopy. Variations in the quantitative wood anatomical features in R. stylosa were assessed in details. Relationships between soil physicochemical variables and the quantitative wood anatomical features were analyzed by means of statistical methods.

Some common specialized wood structures were observed in R. stylosa growing in different habitats, suggesting that these features may function for safely conducting water under high negative pressure and are thus adaptive to intertidal habitats. These common features include the occurrence of: 1) some fibriform vessel elements and a few vasicentric tracheids; 2) vesturing in pits of vessels and helical structures on vessel walls; 3) growth rings; 4) starch grains in ray cells and septate fibers. The quantitative anatomical characteristics have great plasticity in response to heterogeneous habitats. Stepwise regression analyses revealed that the total salt, contents of Mn²⁺, Na⁺, Cl^-, Ca²⁺, organic matters, and total phosphorus of soils, and soil pH all have significant effects on quantitative wood anatomical features. Variations in the quantitative wood anatomical features in R. stylosa growing at different sites are adaptive to fluctuating environmental conditions in the intertidal areas.

Excessive growth of undesired plants, including ruderal natives and tall wetland species, posts great threat to wetland restoration. In this study, we examined the seed germination of Phragmites australis, an undesired species, to evaluate its impact on the restoration of desired Scirpus planiculmis and to provide scientific basis for vegetation management in Momoge wetland.

The germination experiment was conducted in incubators to examine the effects of light intensity (full light, green shade and dark environment) and water depth (0, 5, 15 and 30 cm), based on field observation, on seed germination of P. australis.

Percentage germination of P. australis was significantly higher under “green shade” or “dark” environment than under “full light”. The species had the highest germination rate (86.67% ± 2.36%) at 0 cm water depth under the three light conditions. The interaction between light intensity and water depth on seed germination was significant (p < 0.05) indicating that under different light conditions, increase of water depth decreased seed germination rates at different degrees. We recommend to remove the litter and P. australis to increase light penetration, and to maintain a stable water depth for effectively inhibiting the regeneration of Phragmites and enhance the restoration of S. planiculmis.