Treesearch

Pinus aristata, Rocky Mountain bristlecone pine, has a narrow geographic and elevational distribution and is threatened by rapid climate change, the introduced pathogen Cronartium ribicola that causes white pine blister rust (WPBR), and bark beetles. The core distribution of P. aristata is near and at treeline in central and southern Colorado and extends into northern New Mexico with a disjunct population in northern Arizona. The combination of low genetic diversity, moderate population isolation, and a protracted regeneration dynamic puts populations at risk for extirpation by novel...

Delamination and decay are common structural defects in old glued laminated timber (glulam) buildings, which, if left undetected, could cause severe structural damage. This paper presents a new damage detection method for glulam inspection based on moment analysis and wavelet transform (WT) of impact acoustic signals. Acoustic signals were collected from a glulam arch section removed from service through impact testing at various locations. The presence and positions of internal defects were preliminarily determined by applying time centroid and frequency centroid of the first moment....

Yellowwood (Cladrastis kentukea) is an uncommon, relict, tree species with a disjunct distribution primarily in the Central Hardwoods region. Most common on rocky, sheltered slopes of the Cumberland Plateau in Tennessee and Kentucky, isolated populations occur on appropriate sites throughout the southern and central United States. In Illinois, Louisiana, and South Carolina, yellowwood is listed as endangered by state conservation agencies, but it is not federally protected. Yellowwood has increased in popularity as a street tree and is planted in or predicted to be suitable for urban...

Koa (Acacia koa) is a valuable tree species economically, ecologically, and culturally in Hawaii. A vascular wilt disease of koa, caused by the fungal pathogen Fusarium oxysporum f. sp. koae (FOXY), causes high rates of mortality in field plantings and threatens native koa forests in Hawaii. Producing seeds with genetic resistance to FOXY is vital to successful koa reforestation and restoration. The Hawaii Agriculture Research Center (HARC), with both public and private partners, operates a tree improvement program to develop koa wilt resistant populations in Hawaii. The population...

Recently, a collaboration between The Brenton Arboretum and the North Central Regional Plant Introduction Station (NCRPIS) was initiated to assemble comprehensive ex situ germplasm collections of Kentucky coffeetree, Gymnocladus dioicus. Gymnocladus dioicus was selected due to its adaptation to poor soils common to urban conditions, extreme drought tolerance, and no reported serious insect or disease problems. These factors make it a promising candidate among diverse tree genera to replace ash trees in urban environments affected by the emerald ash borer (Agrilus planipennis). Targeted...

Key elastic properties of full-sized wood composite panels (WCPs) must be accurately determined not only for safety, but also serviceability demands. In this study, the modal parameters of full-sized WCPs supported on four nodes were analyzed for determining the modulus of elasticity (E) in both major and minor axes, as well as the in-plane shear modulus of panels by using a vibration testing method. The experimental modal analysis was conducted on three full-sized medium-density fiberboard (MDF) and three full-sized particleboard (PB) panels of three different thicknesses (12, 15, and 18...

Restoration treatments in the ponderosa pine (Pinus ponderosa P. & C. Lawson) ecosystems of the southwestern United States often include removing over 80 percent of post-EuroAmerican settlement-aged trees to create healthier forest structural conditions. These types of stand density reductions can have negative effects on genetic diversity. Allozyme analyses were used to evaluate potential impacts of restoration treatments on genetic diversity of five ponderosa pine populations located 2 to 3 km apart within the U.S. Department of Agriculture Forest Service Fort Valley Experimental Forest,...

Because of rapid global warming, it is critical for us to better understand the capacity of forest trees to adapt to a changing climate, especially species such as five-needle pines that are particularly at risk to threats because of fire suppression, population fragmentation, and pests. In this study, we used several methods to disentangle the effects of local adaptation (isolation by environment, IBE) from those of isolation by distance (IBD) and isolation by colonization (IBC) in Pinus strobus. For this reason, 153 SNPs from 103 genes, including 44 candidate genes for growth and...

Flexible porous membranes have attracted increasing scientific interest due to their wide applications in flexible electronics, energy storage devices, sensors, and bioscaffolds. Here, inspired by nature, we develop a facile and scalable top-down approach for fabricating a superflexible, biocompatible, biodegradable three-dimensional (3D) porous membrane directly from natural wood (coded as flexible wood membrane) via a one-step chemical treatment. The superflexibility is attributed to both physical and chemical changes of the natural wood, particularly formation of the wavy structure...

Ability to determine stresses in loaded, perforated cellulosic-manure composites from recorded temperature information was demonstrated. Being able to stress analyze such green materials addresses several societal issues. These include providing engineering members fabricated from materials that are suitable for developed and developing nations, relieving a troubling by-product of agricultural regions and reducing demands on our landfills. Most engineering applications of these materials necessitate knowing their structural integrity eg capability to evaluate stresses.