Treesearch

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,...

This paper summarizes the historical environmental context of the Saline-Fifteen site (3BR119) in Bradley County, Arkansas, developed from the General Land Office (GLO) public land surveys, other old documents, and an examination of current forest inventories and modern research to approximate past environmental attributes for this locality. While an imperfect source of information, the 1827-1841 GLO surveys for the Saline-Fifteen locality recorded at least 3,808 witness trees from a minimum of 45 taxa (assuming no grievous taxonomic identification errors). Oaks, pines, gums, and hickories...

A major ice storm struck Georgia and the Carolinas in February of 2014, damaging or destroying hundreds of thousands of hectares of timber worth hundreds of millions of dollars. Losses were particularly severe in pine plantations in west-central South Carolina, including many on the Savannah River Site (SRS). An array of paired, mid-rotation loblolly (Pinus taeda L.) and longleaf (Pinus palustris Mill.) pine plantations on the SRS provided an opportunity to evaluate species- and size-based tree responses to this storm. A preliminary assessment of these recently thinned plantations found...

This study assessed the effects of spacing and genotype on the growth and physiology of improved loblolly pine (Pinus taeda L.) seedlings from three distinct genotypes planted in Drew County, Arkansas (USA). Genotype had a significant effect on survival and height. Clone CF Var 1 showed greater height and survival compared to other seedlings. Genotype had significant effects on uniformity in height both years and ground line diameter (GLD) first year. However, genotype had no significant effects on leaf water potential and coefficient variation of leaf water potential. These growth and...

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...

The interaction of converging fires often leads to significant changes in fire behavior, including increased flame length, angle, and intensity. In this paper, the fluid mechanics of two adjacent line fires are studied both theoretically and experimentally. A simple potential flow model is used to explain the tilting of interacting flames towards each other, which results from a momentum imbalance triggered by fire geometry. The model was validated by measuring the velocity field surrounding stationary alcohol pool fires. The flow field was seeded with high-contrast colored smoke, and the...

Recently, synchrotron based X-ray fluorescence microscopy (XFM) and X-ray absorption near edge spectroscopy (XANES) were used to examine the metal fastener corrosion in copper-treated wood. XFM is able to map the copper concentration in the wood with a spatial resolution of 0.5 µm and is able to quantify the copper concentration to within 0.05 µg cm-3. XANES was used as a complimentary technique to differentiate between oxidation states of copper in the wood. While the primary goal of these measurements was to better understand the corrosion mechanisms, the measurements also give insights...

Shortleaf pine (Pinus echinata Mill.) is an important conifer in much of the southeastern United States. However, the species and its associated ecosystems are in decline, and recent evidence about hybridization with loblolly pine (Pinus taeda L.) raises concerns that the species may be at risk of further losses due to introgression. Although shortleaf pine is not widely planted for timber production, the US Department of Agriculture (USDA) Forest Service, state forestry agencies, some conservation organizations, and private landowners use artificial regeneration to regenerate shortleaf...

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,...