Treesearch

Recently, Buchanan County, Iowa, has cooperated with the U.S. Federal Highway Administration (FHWA), USDA Forest Service, Forest Products Laboratory (FPL), and Iowa State University’s Bridge Engineering Center (ISU–BEC) to initiate a project involving the construction and monitoring of a glued-laminated (glulam) timber superstructure on geosynthetic reinforced soil (GRS) integrated bridge system (IBS) abutments. The research team from FPL installed sensors in the substructure as well as in the bearings of the girders. In addition, the research team from ISU– BEC installed sensors on the...

A combination of experimental, theoretical and numerical studies is used to investigate the variation of elastic moduli of lignocellulosic (bamboo) fiber cell walls with moisture content (MC). Our Nanoindentation results show that the longitudinal elastic modulus initially increased to a maximum value at about 3% MC and then decreased linearly with increasing MC. In contrast, the transverse moduli decrease linearly with MC. We showed that amorphous materials in cell walls have key roles in the variation of elastic modulus with increasing MC. Elastic modulus of lignin, calculated by...

United States tree species and their associated ecosystems, managed forests, and urban plantings are increasingly vulnerable to non-native invasive pathogens and insects as well as effects associated with a changing climate. Some species, such as whitebark pine (Pinus albicaulis), have been proposed for listing under the Endangered Species Act. To fully assess the vulnerability of tree species and ecosystems, we need to make better use of data that shows temporal trends in mortality and forest health. With these data, forest managers and the United States public will have a greater sense...

A collaborative team of researchers from the United States and Mexico has begun an exciting new research project funded by The National Science Foundation’s Macrosystems Biology program. The project will study ecological and evolutionary processes affecting the distribution of southwestern white pine (Pinus strobiformis), an important tree species of mixed conifer forests in the southwest United States and Mexico. Southwestern white pine sustainability is threatened by changing climate, and a non-native tree disease, white pine blister rust caused by Cronartium ribicola. White pine blister...

The ecologically foundational species eastern hemlock, Tsuga canadensis, is being functionally eliminated from southern Appalachian forests by the hemlock woolly adelgid (HWA, Adelges tsugae). The management of HWA has focused on chemical and biological control, conservation of hemlock genetic resources, and host resistance breeding; however, research on the reintroduction of hemlocks to forests where it has been lost has received almost no attention. This poster presents progress made on phase one of a three phase project to develop a hemlock restoration strategy that integrates silvicultu...

Individual behavior is influenced by factors intrinsic to the decision-maker but also associated with other individuals and their ownerships with such relationship intensified by geographic proximity. The land management literature is scarce in the spatially integrated analysis of biophysical and socio-economic data. Localized land management decisions are likely driven by spatially-explicit but often unobserved resource conditions, influenced by an individual's own characteristics, proximal lands and fellow owners. This study examined stated choices over the management of family-owned...

In the United States, 58% of the 11 million family forest ownerships with at least 10 acres of forestland have at least one female owner. Within the single-owner population of landowners, women are the sole owners of and primary decisionmakers for 31% of ownerships. Despite the number of female family forest owners (FFOs), little research has focused on whether land-use and land-management attitudes and behaviors differ between female and male FFOs. This research uses data from the 2013 iteration of the US Department of Agriculture Forest Service's National Woodland Owner Survey. Random...

Picea chihuahuana is an endemic species in Mexico and is considered endangered, according to the Mexican Official Norm (NOM-ECOL-059-2010). This species covers a total area of no more than 300 ha located in at least 40 sites along the Sierra Madre Occidental in Durango and Chihuahua states. A minimum of 42,600 individuals has been estimated, although the number of mature individuals is uncertain and could be less than 2,500. The size of the populations varies from 21 to 5,546 individuals, including trees, saplings, and seedlings. Theory suggests that small populations can be more susceptibl...

Investigating how genetic variation is distributed across the landscape is fundamental to inform forest conservation and restoration. Detecting spatial genetic discontinuities has value for defining management units, germplasm collection, and target sites for reforestation; however, inappropriate sampling schemes can misidentify patterns of genetic structure. Appropriate sampling is more critical in fragmented landscapes where patterns of genetic diversity and structure might not yet reflect the current landscape structure. Landscape genetic simulations are useful for assessing the...

Whitebark pine (Pinus albicaulis) and foxtail pine (P. balfouriana) are conifers native to western North America. Due to several threats, including a non-native pathogen (Cronartium ribicola) and a changing climate, whitebark pine and foxtail pine are classified on the IUCN Red List as ‘endangered’ and ‘near threatened,’ respectively. Whitebark pine has been proposed for listing under the Endangered Species Act (ESA) in the United States and is now listed as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Ex situ genetic conservation activities are...