Treesearch

The vast extent and inaccessibility of boreal forest ecosystems are barriers to routine monitoring of forest structure and composition. In this research, we bridge the scale gap between intensive but sparse plot measurements and extensive remote sensing studies by collecting forest inventory variables at the plot scale using an unmanned aerial vehicle (UAV) and a structure from motion (SfM) approach. At 20 Forest Inventory and Analysis (FIA) subplots in interior Alaska, we acquired overlapping imagery and generated dense, 3D, RGB (red, green, blue) point clouds. We used these data to model...

Lidar provides critical information on the three-dimensional structure of forests. However, collecting wall-towall laser altimetry data at regional and global scales is cost prohibitive. As a result, studies employing lidar for large area estimation typically collect data via strip sampling, leaving large swaths of the forest unmeasured by the instrument. The goal of this research was to develop and examine the performance of a coregionalization modeling approach for combining field measurements, strip samples of airborne lidar and Landsat-based remote sensing products to predict abovegroun...

Inbreeding has been difficult to quantify in wild populations because of incomplete parentage information. We applied and extended a recently developed framework for addressing this problem to infer inbreeding rates in Northern Spotted Owls (Strix occidentalis caurina) across the Pacific Northwest, USA. Using pedigrees from 14,187 Northern Spotted Owls, we inferred inbreeding rates for 14 types of matings among relatives that produce pedigree inbreeding coefficients of F=0.25 or F=0.125. Inbreeding was most common in the Washington Cascades, where an estimated 15% of individuals are...

Aims: Species distributions are hypothesized to be underlain by a complex association of processes that span multiple spatial scales including biotic interactions, dispersal limitation, fine‐scale resource gradients and climate. Species disequilibrium with climate may reflect the effects of non‐climatic processes on species distributions, yet distribution models have rarely directly considered non‐climatic processes. Here, we use a Joint Species Distribution Model (JSDM) to investigate the influence of non‐climatic factors on species co‐occurrence patterns and to directly quantify the...

Premise of the Study: Changing climates are expected to affect the abundance and distribution of global vegetation, especially plants and lichens with an epiphytic lifestyle and direct exposure to atmospheric variation. The study of epiphytes could improve understanding of biological responses to climatic changes, but only if the conditions that elicit physiological performance changes are clearly defined. Methods: We evaluated individual growth performance of the epiphytic lichen Evernia mesomorpha, an iconic boreal forest indicator species, in the first year of a decade-long experiment...

The effects of ecosystem degradation are pervasive worldwide and increasingly concerning under the present context of global changes in climate and land use. Theoretical studies and empirical evidence increasingly suggest that drylands are particularly prone to develop nonlinear functional changes in response to climate variations and human disturbance. Precipitation-use efficiency (PUE) represents the ratio of vegetation production to precipitation and provides a tool for evaluating human and climate impacts on landscape functionality. Holm oak (Quercus ilex) woodlands are one of the most...

Accurate measurements of natural resources are a prerequisite for resource assessment. Demetrios Gatziolis, a scientist with the USDA Forest Service Pacific Northwest Research Station, and his colleagues with Washington State University developed and tested protocols for using structure-from-motion photogrammetry to obtain data that can be used to construct 3-dimensional (3-D) representations of trees, other vegetation, and down wood. This type of photogrammetry is a remote-sensing technique based on a sequence of digital images or video footage. Gatziolis and his colleagues focused on...

Publishing of scientific findings is central to the scientific process, and it is traditional to consider findings ‘‘provisional’’ until accepted by a peer-reviewed journal. Until publication, communication of provisional findings beyond participants in the study is typically limited. This practice helps assure scientific integrity. However, a dilemma arises when a provisional finding has urgent societal consequences that may be exacerbated by delay. This dilemma may be particularly pronounced when a discovery concerns wildlife health, which could have implications for conservation, public...

Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region. We find that 31% of all study citations are derived from sites located within 50 km of just...

National forests and grasslands in the United States are governed by land and resource management plans that should be updated every 15 years to reflect changing social, economic, and environmental conditions and to address new priorities. A new forest planning rule finalized in 2012 introduces new planning approaches and requirements, and several forests have completed the forest assessment phase of their planning process. Using document analysis and interview data, we analyzed four completed forest assessments to gain insights into early forest planning efforts under the 2012 rule. We...