Plant economic strategies in two contrasting forests.

Background: Predicting relationships between plant functional traits and environmental effects in their habitats is a central issue in terms of classic ecological theories. Yet, only weak correlation with functional trait composition of local plant communities may occur, implying that some essential information might be ignored. In this study, to address this uncertainty, the objective of the study is to test whether and how the consistency of trait relationships occurs by analyzing broad variation in eight traits related to leaf morphological structure, nutrition status and physiological activity, within a large number of plant species in two distinctive but comparable harsh habitats (high-cold alpine fir forest vs.

Climate extremes drive the phenology of a dominant species in meadow steppe under gradual warming.

Plant phenology in terrestrial ecosystems, especially in the Northern Hemisphere, is expected to change owing to the projected increasing frequency and intensity of climate extremes in the context of global warming. Although such changes under mean climate change have been extensively reported in the literature, little is known about the impacts of climate extremes. In this study, climatic changes and their effects on plant phenology were characterized using long-term climatic and phenological data from the start and end of the growing season (SOS and EOS, respectively) from 2005 to 2020 for Stipa baicalensis, a dominant species in a temperate meadow steppe.

Mapping Chinese annual gross primary productivity with eddy covariance measurements and machine learning.

Annual gross primary productivity (AGPP) is the basis for grain production and terrestrial carbon sequestration. Mapping regional AGPP from site measurements provides methodological support for analysing AGPP spatiotemporal variations thereby ensures regional food security and mitigates climate change. Based on 641 site-year eddy covariance measuring AGPP from China, we built an AGPP mapping scheme based on its formation and selected the optimal mapping way, which was conducted through analysing the predicting performances of divergent mapping tools, variable combinations, and mapping approaches in predicting observed AGPP variations.

Growth variations of Dahurian larch plantations across northeast China: Understanding the effects of temperature and precipitation.

Climate change is affecting the growth and distribution of trees in the Chinese boreal forest. Such changes in China, the southern terminus of the extensive Eurasian boreal forests, reflect on the changes that could occur further north under a warming climate. Most studies have found that tree growth increases with increasing temperature and precipitation in boreal forests, but there is little observational evidence of the climate thresholds that might slow these growth rates at the more extreme temperatures which are predicted to occur under future global warming.

Elevated-CO2 Response of Stomata and Its Dependence on Environmental Factors.

Stomata control the flow of gases between plants and the atmosphere. This review is centered on stomatal responses to elevated CO2 concentration and considers other key environmental factors and underlying mechanisms at multiple levels. First, an outline of general responses in stomatal conductance under elevated CO2 is presented.

[Impact of fire on carbon dynamics of Larix gmelinii forest in Daxing'an Mountains of North-East China: a simulation with CENTURY model].

Fire is one of the important natural disturbances to forest ecosystem, giving strong impact on the ecosystem carbon dynamics. By using CENTURY model, this paper simulated the responses of the carbon budget of Larix gmelinii forest in Huzhong area of Daxing' an Mountains to different intensities of fire. The results indicated that after the fires happened, the soil total carbon pool of the forest had a slight increase in the first few years and then recovered gradually, while the stand biomass carbon pool increased after an initial decrease, with the recovery rate of carbon pool of the stand fine components being faster than that of the coarse components.

[Relationships of forest fire with lightning in Daxing' anling Mountains, Northeast China].

Forest fire is an important factor affecting forest ecosystem succession. Recently, forest fire, especially forest lightning fire, shows an increasing trend under global warming. To study the relationships of forest fire with lightning is essential to accurately predict the forest fire in time.

Monitoring nitrogen deposition in typical forest ecosystems along a large transect in China.

The nitrogen (N) deposition fluxes were investigated in eight typical forest ecosystems along the North-South Transect of Eastern China (NSTEC; based on the ChinaFLUX network) by ion-exchange resin (IER) columns from May 2008 to April 2009. Our results demonstrated that the method of IER columns was both labor cost saving and reliable for measuring dissolved inorganic nitrogen (DIN) deposition at the remote forest stations. The deposition of DIN in the throughfall ranged from 1.

[Carbon exchange of Chinese boreal forest during its growth season and related regulation mechanisms].

Based on the two-year continuous observation on the carbon exchange of Chinese boreal forest during its growth seasons in 2007 and 2008 by the method of open path eddy covariance, this paper analyzed the seasonal dynamics of the gross ecosystem productivity (GEP), ecosystem respiration (Re), and net ecosystem carbon exchange (NEE) of the forest, with related regulation mechanisms approached. The GEP, Re, and NEE of the forest reached to their maximum in the vigorous growth period from late June to mid August, but the dates of the maximum appeared differed. The mean daily GEP, Re, and NEE were 19.

[Biomass allocation of Leymus chinensis population: a dynamic simulation study].

Based on a greenhouse simulation experiment, this paper studied the dynamics of the above- and below-ground biomass of Leymus chinensis populations with four planting densities (120, 240, 360 and 480 plants x m(-2)). The results showed that the above- and below-ground biomass of L. chinensis populations had an increasing trend with the growth, and increased with increasing planting density.

Toward a general evaluation model for soil respiration (GEMSR).

Soil respiration is an important component of terrestrial carbon budget. Its accurate evaluation is essential to the study of terrestrial carbon source/sink. Studies on soil respiration at present mostly focus on the temporal variations and the controlling factors of soil respiration, but its spatial variations and controlling factors draw less attention.

[Affecting factors of soil microorganism and root respiration].

Soil respiration is an important part of the carbon cycle in terrestrial ecosystems, and its contribution to the global carbon budget has been the focus of wide concern. Researches on the affecting factors of soil microorganism and root respiration, the main components of soil respiration, contribute to the understanding of the role of soil respiration on global carbon cycle, and to the accurate evaluation of global carbon budget. This paper reviewed the direct and indirect affecting factors of soil microorganism and root respiration, including climate factors, soil properties, vegetation and litterfall, air CO2 concentration, and human activities.

[A comparative study on soil respiration between grazing and fenced typical Leymus chinensis steppe, Inner Mongolia].

With enclosed chamber Method, this paper studied the soil respiration in grazing and fenced typical Leymus chinensis steppes, Inner Mongolia, and its relationships with environmental factors. The results showed that the daily pattern of soil respiration could be expressed as a one-humped curve, and the highest values appeared at 13:00-15:00 in the fenced and grazing plots. The diurnal dynamics of soil respiration mainly depended on the surface temperature at the fenced plots and the soil temperature at 5 cm depth at the grazing plots.

[Evaluation of agricultural net primary productivity in Yijinhuoluo County, Inner Mongolia].

An agricultural net primary productivity model considering both climatic and fertilizer factors was presented, with referencing over 40 years (1959-1998) climatic and agricultural data from Yijinhuoluo County. Based on the scenarios of climate, population and human activities (mainly fertilization) in the next 30 years as well as the demand of local people for food, the changes of the crop area were evaluated. As a result, 622-5948 hm2 could be converted into grassland and forest land from now to the year of 2010, amounting to 3%-31% of the average area between 1990 and 1998; from 2010 to 2020, the converted area should be 3263-8164 hm2, amounting to 17%-42%.