Treesearch

China launched the ‘‘Returning Grazing Lands to Grasslands’’ project about a decade ago to restore severely degraded grasslands. Grassland grazing exclusion was one of the experimental approaches for achieving the grand goal. Here, we evaluate the long-term regional ecological effects of grassland grazing exclusion in the Xilingol region of Inner Mongolia, China. The dynamics of grassland communities over 8 years (2004–2011) were continuously monitored at 11 research sites dominated by temperate steppe ecosystems. These sites represent the diverse landscapes of the Mongolian Plateau in the...

Ecosystem services are increasingly recognized as the foundations of a well-functioning society. Large-scale ecological restoration projects have been implemented around China with the goal of restoring and sustaining ecosystem services, especially in vulnerable semi-arid regions where soil and water resources are most stressed due to historic human activities. The relationships among ecosystem services are often driven by land-use changes. It is necessary to develop an applicable method to explore the relationships between ecosystem services and driving factors over time. We selected the...

A large area of plantations has been established worldwide and especially in China. Evaluating the restoration status of these plantations is essential for their longterm management. Based on our previous work, we used an ecological memory (EM) approach to evaluate four 26-year-old plantations that represent four common kinds of plantations in subtropical China, i.e., mixed broad-leaved plantation (MBP), mixed coniferous plantation (MCP), eucalyptus plantation (EP), and mixed legume plantation

The effects of a transatlantic trade agreement on the global forest sector were assessed with the Global Forest Products Model, conditional on previous macroeconomic impacts predicted with a general equilibrium model. Comprehensive tariff elimination per se had little effect on the forest sector. However, with deeper reforms and integration consumption would increase twice as much in percent in the US as in the EU. Net trade decreased in the US more than in the EU while it increased in Asia. Consumers and producers’ welfare increased by $7000 million in the EU and $14,000 million in the...

Changes in winter precipitation that include both decreases and increases in winter snow are underway across the Arctic. In this study, we used a 14-year experiment that has increased and decreased winter snow in the moist acidic tussock tundra of northern Alaska to understand impacts of variation in winter snow depth on summer leaf-level ecophysiology of two deciduous shrubs and a graminoid species, including: instantaneous rates of leaf gas exchange, and δ13C, δ15N, and nitrogen (N) concentrations of Betula nana, Salix pulchra, and Eriophorum vaginatum. Leaf-level measurements were...

S-adenosylmethionine (SAM), a major substrate in 1-C metabolism is a common precursor in the biosynthetic pathways of polyamines and ethylene, two important plant growth regulators, which exhibit opposing developmental effects, especially during fruit ripening. However, the flux of various substrates including SAM into the two competing pathways in plants has not yet been characterized. We used radiolabeled 14C-Arg, 14C-Orn, L-[U-14C]Met, 14C-SAM and 14C-Put to quantify flux through these pathways in tomato fruit and evaluate the effects of perturbing these pathways via transgenic expressio...

Despite growing interest in using switchgrass (Panicum virgatum L.) as a biofuel, there are limiteddata on the physiology of this species and its effect on stand water use and carbon (C) assimilationwhen grown as a forest intercrop for bioenergy. Therefore, we quantified gas exchange rates of switch-grass within intercropped plots and in pure switchgrass plots during its second growing season in anintensively managed loblolly pine (Pinus taeda L.) plantation in North Carolina. Switchgrass physiol-ogy was characterized over the growing season from June to October 2010 in terms of photosynthe...

The history of watershed research in the Interior Highlands can be divided into four periods: Initial Start and Stumble (1930s–1950s), Reestablishment and Renewal (1960–1980), Partnerships and Expansion (1980–1990), and New Scales and Paths (1990–present). While each of these periods was marked by different societal concerns and scientific questions, experimental forests played a central role in accomplishing watershed research during all of these periods. Unlike other regions of the country, there was no dominating theme or inspirational leader to focus watershed research in one particular...

A Recovery Plan developed for the threatened Mexican Spotted Owl (Strix occidentalis lucida) recommended designating Protected Activity Centers (PACs) with a minimum size of 243 ha to conserve core use areas of territorial owls. The plan assumed that areas of this size would protect " the nest site, several roost sites, and the most proximal and highly-used foraging areas." The PAC concept remains an important component of the recovery strategy nineteen years later, although use of designated PACs by territorial owls has never been evaluated. We assessed use of PACs for nesting and...

Seagrasses around the world are threatened by human activities that degrade water quality and reduce light availability. In this study, light requirements were determined for four common and abundant seagrasses along the Gulf coast of peninsular Florida using a threshold detecting algorithm. Light requirements ranged from 8% to 10% of surface irradiance for Halophila engelmannii to 25–27% of surface irradiance for Halodule wrightii. Requirements for all species differed from previous reports generated at other locations. Variations were attributed to morphological and physiological...