Treesearch

The article, intended for professional and manager audiences, is an overview of current research in urban forestry. Topics include tree science, forest risks, forest management and assessment, ecosystem services, and urban socio-ecological systems (including governance and stewardship).

Streamflow and water temperature (hydroclimate) influence the life histories of aquatic biota. The relationship between streamflow and temperature varies with climate, hydrogeomorphic setting, and season. Life histories of native fishes reflect, in part, their adaptation to regional hydroclimate (flow and water temperature), local habitats, and natural disturbance regimes, all of which may be affected by water management. Alterations to natural hydroclimates, such as those caused by river regulation or climate change, can modify the suitability and variety of in-stream habitat for fishes...

Mammalian herbivory can have profound impacts on plant population and community dynamics. However, our understanding of specific herbivore effects remains limited, even in regions with high densities of domestic and wild herbivores, such as the semiarid conifer forests of western North America. We conducted a seven-year manipulative experiment to evaluate the effects of herbivory by two common ungulates, Cervus elaphus (Rocky Mountain elk) and cattle Bos taurus (domestic cattle) on growth and survival of two woody deciduous species, Populus trichocarpa (cottonwood) and Salix scouleriana...

Phylogenetics benefits from using a large number of putatively independent nuclear loci and their combination with other sources of information, such as the plastid and mitochondrial genomes. To facilitate the selection of orthologous low-copy nuclear (LCN) loci for phylogenetics in nonmodel organisms, we created an automated and interactive script to select hundreds of LCN loci by a comparison between transcriptome and genome skim data. We used our script to obtain LCN genes for southern African Oxalis (Oxalidaceae), a speciose plant lineage in the Greater Cape Floristic Region. This...

We examined landscape exposure to wildfire potential, insects and disease risk, and urban and exurban development for the conterminous US (CONUS). Our analysis relied on spatial data used by federal agencies to evaluate these stressors nationally. We combined stressor data with a climate change exposure metric to identify when temperature is likely to depart from historical conditions and become ‘‘unprecedented.’’ We used a neighborhood analysis procedure based on key stressor thresholds within a geographic information system to examine the extent of landscape exposure to our set of...

Our documentation of Sartwell’s Sedge, Carex sartwellii, on nine shrinking lakes during fieldwork in the central Yukon Flats, Alaska, represents a range extension for this species. Previously, its range extended as far northwest as Yukon, Canada, with a reported, but lost collection, from Alaska in 1895. Two earlier collections from the Yukon Flats have been verified; one was misidentified as Carex praegracilis until 2007. Carex sartwellii’s assumed absence from Alaska and Yukon flora, misidentification of an earlier collection, and the remoteness of the Yukon Flats may have contributed to...

Wetland determination relies on assumptions that site hydrologic and edaphic conditions limit plant species to certain environments. For example, using species' wetland indicator status for wetland determination assumes that tolerance of wetland conditions best explains distributional patterns. However, abiotic and biotic factors often interact to create complex plant responses across different environments. To evaluate these interactions, we used a hydrologic gradient in the coastal temperate rainforest of southeast Alaska to (1) quantify the primary determinants of conifer distributions,...

Despite its wide geographic distribution and important role in boreal forest fire regimes, little is known about the climate-growth relationships of black spruce (Picea mariana [Mill.] B.S.P.). We used site- and tree-level analyses to evaluate the radial growth responses to climate of black spruce growing on a north-facing toposequence in interior Alaska for the period A.D. 1949–2010. At the site level, correlations between growth and climate were negative for temperature and positive for precipitation. The signs and strengths of these correlations varied seasonally and over time. These...

Climate change will likely have significant effects on forest ecosystems worldwide. In Mediterranean regions, such as that in southwestern Oregon, USA, changes will likely be driven mainly by wildfire and drought. To minimize the negative effects of climate change, resource managers require tools and information to assess climate change vulnerabilities and to develop and implement adaptation actions. We developed an approach to facilitate development and implementation of climate change adaptation options in forest management. This approach, applied in a southwestern Oregon study region,...

The purpose of this study was to enhance the understanding of the health-promoting potential of trees in an urbanized region of the United States. This was done using high-resolution LiDAR and imagery data to quantify tree cover within 250 m of the residence of 7910 adult participants in the California Health Interview Survey, then testing for main and mediating associations between tree cover and multiple health measures. The results indicated that more neighborhood tree cover, independent from green space access, was related to better overall health, primarily mediated by lower overweight...