Treesearch

Determining adhesive bond performance for chemically modifed wood is important not only for its commercial utility but also for understanding wood bond durability. Bulking modifications occupy space inside the cell wall, limiting the space available for water. We used two bulking modifcations on yellow poplar (Liriodendron tulipifera L.): acetylation (Ac), which bulks and converts a wood hydroxyl group to an ester, while butylene oxide (BO) also bulks the wood but preserves a hydroxyl group. Both result in lower water uptake; however, the loss of the hydroxyl group with Ac reduces the...

A method for the large-eddy simulation (LES) of wildfire spread over complex terrain is presented. In this scheme, a cut-cell immersed boundary method (CC-IBM) is used to render the complex terrain, defined by a tessellation, on a rectilinear Cartesian grid. Discretization of scalar transport equations for chemical species is done via a finite volume scheme on cut-cells defined by the intersection of the terrain geometry and the Cartesian cells. Momentum transport and heat transfer close to the immersed terrain are handled using dynamic wall models and a direct forcing immersed boundary...

Cellulose nanomaterials (CNMs), mainly including nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNCs), have attained enormous interest due to their sustainability, biodegradability, biocompatibility, nanoscale dimensions, large surface area, facile modification of surface chemistry, as well as unique optical, mechanical, and rheological performance. One of the most fascinating properties of CNMs is their aqueous suspension rheology, i.e., CNMs helping create viscous suspensions with the formation of percolation networks and chemical interactions (e.g., van der Waals forces,...

This resource update contains the findings of a canvass of all primary wood-using plants. It complements the Forest Inventory and Analysis (FIA) annual inventory of volume and removals. The canvass was conducted to determine the amount and source of wood receipts and annual timber product imports/exports. Only primary wood-using mills were canvassed. Primary mills are those that process roundwood in log or bolt form or as chipped roundwood. Examples of industrial roundwood products are saw logs, pulpwood, veneer logs, poles, and logs used for composite board products. Mills producing...

This resource update contains the findings of a canvass of all primary wood-using plants. It complements the Forest Inventory and Analysis (FIA) annual inventory of volume and removals. The canvass was conducted to determine the amount and source of wood receipts and annual timber product imports/exports. Only primary wood-using mills were canvassed. Primary mills are those that process roundwood in log or bolt form or as chipped roundwood. Examples of industrial roundwood products are saw logs, pulpwood, veneer logs, poles, and logs used for composite board products. Mills producing...

Redlining was a racially discriminatory housing policy established by the federal government's Home Owners' Loan Corporation (HOLC) during the 1930s. For decades, redlining limited access to homeownership and wealth creation among racial minorities, contributing to a host of adverse social outcomes, including high unemployment, poverty, and residential vacancy, that persist today. While the multigenerational socioeconomic impacts of redlining are increasingly understood, the impacts on urban environments and ecosystems remain unclear. To begin to address this gap, we investigated how the...

Changing wildfire regimes are causing rapid shifts in forests worldwide. In particular, forested landscapes that burn repeatedly in relatively quick succession may be at risk of conversion when pre-fire vegetation cannot recover between fires. Fire refugia (areas that burn less frequently or severely than the surrounding landscape) support post-fire ecosystem recovery and the persistence of vulnerable species in fire-prone landscapes. Observed and projected fire-induced forest losses highlight the need to understand where and why forests persist in refugia through multiple fires. This...

Conservation management is deploying increasingly intensive strategies to maintain biodiversity and ecosystem function in response to global anthropogenic threats. These strategies include intentionally introducing and eradicating species around the world via assisted migration, rewilding, biological control, invasive species eradications, and gene drives - management actions which have become highly contentious because of their potential for unintended consequences. We conducted a global literature review of these conservation actions to quantify how often unintended outcomes occur and to...

1. Although most populations of non-native species arriving in new environments fail to establish, mechanisms behind failed biological invasions are still poorly understood. 2. Propagule pressure has been found to be a dominant driver of establishment success, underpinned by processes such as stochasticity and Allee effects. While studies have revealed the presence of a component Allee effect in field populations, empirical support for demographic Allee effects has been limited. 3. We used the leaf-feeding beetle Neolema ogloblini, a biological control agent against the plant Tradescantiafl...

Landscape-scale maps of tree species densities are important tools for managing ecosystems threatened by forest pests. Eastern hemlock dominates riparian forests throughout its range. As a conifer in a deciduous landscape, hemlock plays an ecohydrological role, especially when other species are dormant. The nonnative, hemlock woolly adelgid has caused widespread hemlock decline and mortality. We used two existing basal area raster layers first to identify Chesapeake Bay subwatersheds with ≥6 percent hemlock basal area and second to quantify hemlock basal area densities within fixed-width...