Treesearch

In this study, the effects of cellulose nanofibrils (CNFs) ratio, press program, particle size, and density on the vertical density profile (VDP) and internal bond (IB) strength of the wet-formed particleboard were investigated. Results revealed that the VDP was significantly influenced by the press program. Pressing using a constant pressure (CP) press program produced panels with flat-shaped profile. Panels made from a constant thickness (CT) press program produced U-shaped profile. The CNF ratio and density also influenced the VDP especially for the CT panels. As the CNF ratio increased,...

Programs aimed at developing clones of hybrid trees are commonly established in Brazil to meet the demands of various forest-based industries. These programs have continually improved the quality of eucalyptus wood, which has the potential to reduce deforestation by lowering demand for other high-value species. This is particularly true in the lumber market, but little is known about the resistance of eucalyptus wood to biodegradation. This study evaluated variation in natural resistance of seven Eucalyptus grandis x Eucalyptus urophylla hybrid clones to decay by four wood-rot fungi and...

Stresses to trees under a changing climate can lead to changes in forest tree survival, mortality and distribution. For instance, a study examining the effects of human-induced climate change on forest biodiversity by Hansen and others (2001) predicted a 32% reduction in loblolly–shortleaf pine habitat across the eastern United States. However, they also predicted an average increase in area of 34% for oak-hickory forests and a 290% increase in oak-pine forests. Drought is often a leading cause of stress and mortality in forest trees (Allen and others 2010, Choat and others 2012).Drought,...

Ex-situ genetic conservation focused on collection and storage of seed can play an important role in conserving the genetic diversity of species under grave threat by biotic organisms or a changing climate. However, ex-situ genetic conservation is primarily a static activity and does not allow for evolution of the species under a continuing, persistent impacting agent. Invasive insects and pathogens, once established, usually become permanent components of the ecosystem, continuously interacting with the target species. Dynamic genetic conservation seeks to actively harness the genetic...

North American native tree species in forest ecosystems, as well as managed forests and urban plantings, are being severely impacted by pathogens and insects. The impacts of these pathogens and insects often increase over time, and they are particularly acute for those species affected by non-native pathogens and insects. For restoration of affected tree species or for their continued presence in managed forests and urban plantings, genetic resistance will be key. Often, however, little or nothing is known about genetic resistance to these invaders. The U.S. Department of Agriculture...

A strong focus on tree germplasm that can resist threats such as non-native insects and pathogens, or a changing climate, is fundamental for successful genetic conservation efforts. However, the unavailability of tools for rapid screening of tree germplasm for resistance to critical pathogens and insect pests is becoming an increasingly serious bottleneck. Here we present the development of a new technique that can potentially revolutionize genetic conservation efforts. Fourier-transform infrared (FT-IR) spectroscopy is a chemical fingerprinting technique that has been recently shown to be...

The American Chestnut Foundation (TACF) has worked since 1983 to introduce genetic resistance to the chestnut blight fungus (Cryphonectria parasitica) into an American chestnut (Castanea dentata) population. As part of a broader goal for species restoration, TACF seeks to instill within that population sufficient diversity so as to enable the species to reproduce on its own in forests throughout its native range. Dr. Charles Burnham proposed introgressing blight-resistance from Asian chestnut species into a predominantly American chestnut genetic background with backcross breeding. Hybrids...

How do we conserve tree diversity in a rapidly changing world, dominated by intensive human impact on the landscape? The Anthropocene is a useful term to describe a new era in Earth’s history, where we dominate the globe’s resources so completely that our activities alter basic nutrient, water, climate, and energy cycles. These rapid environmental changes and the substantial decline in available and appropriate habitat for many organisms has led to predictions of a sixth global extinction event, where a large fraction of the world’s species are lost. These mass extinctions clearly impacted...

Forests are thought to adapt too slowly to anthropogenic climate change, making them highly vulnerable to large-scale loss. Losses can accrue swiftly because generations are lengthy, particularly at higher latitudes (>23⁰ to 73⁰) where wind-pollinated forest species are commonly found to mature slowly. Losses incurred during adaptation to climate change translates into less allelic richness, or genetic diversity, and one can expect some resilience on this point because forests have more genetic diversity than other seed plants and this feature has shaped the forest fragmentation paradox...

Wet-formed particleboard bonded with cellulose nanofibrils (CNF) was prepared in this work. The effects of density, CNF addition ratio, pressing method, and particle size on the bending strength were evaluated. The results showed that density had the most important effect on the modulus of elasticity (MOE), while the CNF addition ratio had the most important effect on the modulus of rupture (MOR). For panels with low density (< 640 kg/m3), the MOE and MOR did not change much with the configuration changes between particle size and pressing method. This was due to the synergistic effect of...