Treesearch

The Micronesia Challenge (MC) is an agreement initiated in 2006 by the region’s political jurisdictions to conserve both marine and terrestrial natural resources. To assess the success of the terrestrial goals of the challenge, the Micronesia Conservation Trust (MCT) coordinated the compilation of a list of terrestrial measures and utilized them to summarize data from the United States Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis (FIA) program. The MCT and FIA programs added and measured additional forest plots within conservation and special management...

Forest wildfires consume and redistribute carbon within forest carbon pools. Because the incidence of wildfires is unpredictable, quantifying wildfire effects is challenging due to the lack of prefire data or controls from experiments over a large landscape. We explored a quasi-experimental method, propensity score matching, to estimate wildfire effects on aboveground forest woody carbon mass in Washington and Oregon, United States. Observational data, including national forest inventory plot measurements and satellite imagery metrics, were utilized to obtain a control set of unburned...

Complex early-seral forests support biological legacies and unique understory vegetation (grasses, forbs, shrubs, juvenile trees) important to wildlife and ecosystem functioning. Intensive management in early-seral forest and other stages could reduce understory plant diversity and homogenize community compositions. Furthermore, the relative effects of management regime may vary at different stages of forest development. To what extent do taxonomic, functional and phylogenetic diversity vary by seral stage and/or ownership (a proxy for management regime) after accounting for climatic...

Systems-based land management frameworks such as ecosystem services can improve cultural resource management and outdoor recreation in natural areas. We analyzed data from a participatory mapping survey of forest values from an ecological restoration area in the East Cascades, which provide conceptual and methodological tools that can be utilized in land management more widely. We also consulted archaeological, paleo-ecological, and traditional land use data to link heritage values with cultural landscapes. Heritage benefits mapped by respondents were associated with connections to...

Fire severity affects both ecosystem N-loss and post-fire N-balance. Climate change is altering the fire regime of interior Alaska, although the effects on Siberian alder (Alnus viridis ssp. fruticosa) annual N-fixation input (kg N ha-1 yr-1) and ecosystem N-balance are largely unknown. We established 263 study plots across two burn scars within the Yukon-Tanana Uplands ecoregion of interior Alaska. Siberian alder N-input was quantified by post-fire age, fire severity, and stand type. We modeled the components of Siberian alder N-input using environmental variables and fire severity within...

Air temperatures (Ta) are rising in a changing climate, increasing extreme temperature events. Examining how Ta increases are influencing extreme temperatures at the soil surface and belowground in the soil profile can refine our understanding of the ecological consequences of rising temperatures. In this paper, we validate surface and soil temperature (Ts: 0–100-cm depth) simulations in the SOILWAT2 model for 29 locations comprising 5 ecosystem types in the central and western USA. We determine the temperature characteristics of these locations from 1980 to 2015, and explore simulations...

Outdoor and nature-based recreation provides countless social benefits, yet public land managers often lack information on the spatial and temporal extent of recreation activities. Social media is a promising source of data to fill information gaps because the amount of recreational use is positively correlated with social media activity. However, despite the implication that these correlations could be employed to accurately estimate visitation, there are no known transferable models parameterized for use with multiple social media data sources. This study tackles these issues by examining...

The Fourth National Climate Assessment (NCA4) provided the most up-to-date understanding of climate change and its effects on the Earth system and on consequences for the United States, including impacts and associated risks, along with approaches to coping with these effects. It is intended to provide guidance to decision-makers in governmental sectors while, in practice, providing guidance for nongovernmental actors. Its regional and topical chapters highlight current knowledge, uncertainties, gaps in knowledge, and emerging threats. The current knowledge and gaps can help set a research...

Strategies for deep soil water acquisition (WAdeep) are critical to a species’ adaptation to drought. However, it is unknown how WAdeep determines the abundance and resource economy strategies of understorey shrub species. With data from 13 understorey shrub species in subtropical coniferous plantations, we investigated associations between the magnitude of WAdeep, the seasonal plasticity of WAdeep, midday leaf water potential (Ψmd), species abundance and resource economic traits across organs. Higher capacity for WAdeep was associated with higher intrinsic water use efficiency, but was...

The ratio of leaf internal (ci) to ambient (ca) partial pressure of CO2, defined here as χ, is an index of adjustments in both leaf stomatal conductance and photosynthetic rate to environmental conditions. Measurements and proxies of this ratio can be used to constrain vegetation model uncertainties for predicting terrestrial carbon uptake and water use. We test a theory based on the least-cost optimality hypothesis for modelling historical changes in χ over the 1951–2014 period, across different tree species and environmental conditions, as reconstructed from stable carbon isotopic...