Treesearch

The fields of tree breeding and genetic engineering can be perceived as being antagonistic towards each other—genetic engineers suggesting that tree breeding is too slow and expensive and tree breeders suggesting that genetic engineering is not practical and too expensive. We argue here that both fields have much to offer forestry and the success of each is intimately tied to the other. The major purposes of genetic engineering in forestry are described as well as the importance of evaluating tree engineering initiatives in the context of tree improvement and silviculture and integrating...

Wildfire burned area, fire size, fire severity and the ecological and socio-economic impacts of fire have been increasing rapidly in California in recent decades. We summarize the record-breaking 2020 wildfire season in California statistically, evaluate the drivers of high-severity burning in the 2020 fires and consider implications for fire and resource management.

Changes in atmospheric pressure continuously ventilate soils and snowpacks. This physical process, known as pressure pumping, is a major factor in the exchange fluxes of H2O, CO2, and other trace gases between the soil and atmosphere. Thus models of pressure pumping are relevant to many areas of critical importance. This study compares the three principal models used to describe pressure pumping. Beginning with the fundamental physical principles and whether the flow field is compressible or incompressible, these models are categorized as linear parabolic (one model - compressible) or...

The effect of foam discontinuity in the shear zone of structural insulated panel (SIP) beams was investigated in the current research. Two depths of 15.24 cm and 31.11 cm (6.5 in. and 12.25 in.) SIPs were evaluated in 1/3-point bending. Panels were sawn into beams, each approximately 29.84 cm (11.75 in.) wide, for the mechanical testing. Half of the panels had joints or discontinuities in the foam layer in a location that was subject to shear stress during the bending tests. Half of the panels did not have joints or discontinuities in the foam layer in the locations that were subject to...

Pyrolysis products from wildland fuels are typically measured under tightly controlled conditions using fuels which have been processed to remove water content and physical shape. Different instruments can be used to identify and quantify the composition of these gases. Measurement of pyrolysis gases under conditions typical of wildland fires has seldom occurred. We used FTIR spectroscopy and GC/FID analysis to measure pyrolysis gases produced in wind tunnel experiments and small prescribed burns in longleaf pine needle fuel beds with live shrubs. Use of compositional data techniques on...

The health benefits of exposure to trees and plants is a rapidly expanding field of study. Research has shown that exposure is associated with improvements in a wide range of health outcomes including cardiovascular disease, birth outcomes, respiratory disease, cancer, mental health and all-cause mortality1. One of the challenges that these studies face is characterizing participants’ exposure to trees and plants. A common approach is to use the normalized difference vegetation index, a greenness index typically derived from satellite imagery. Reliance on the normalized difference vegetatio...

The utility sector has been employing ultrasonic-based nondestructive evaluation (NDE) to determine the cross-sectional groundline integrity of wooden utility poles. While it is far less invasive than other methods, its efficacy has not been thoroughly studied. This study aims to fill this technical gap by analyzing the correlation between the propagational characteristics of the ultrasonic stress wave using a novel embedded waveguide technique and the existing destructive testing methods. The proposed embedded waveguide technique excites diffusive Rayleigh mode (AW2) propagating in the...

Bending modulus of elasticity (MOE) and tensile properties parallel to the grain were studied on 702 pieces of 2 × 6 and 285 pieces of 2 × 10 No. 2 visually graded southern pine lumber. The overall rings per inch (RPI) in 2 × 6 pieces was 4.82, whereas 2 × 10 had an RPI average of 3.82. For latewood percentage (LW), 2 × 6 pieces found 45.88% of LW and 45.02% for 2 × 10 pieces. Bending MOE (Eb) mean for 2 × 6 was 10,615 MPa, whereas for 2 × 10 lumber, the mean was 13,665 MPa. The tension MOE (Et) mean for 2 × 6 lumber was 11,339 MPa, whereas for 2 × 10 the mean was 9735 MPa. The ultimate...

Black spruce forest communities in boreal Alaska have undergone self-replacement succession following low-to-moderate severity fires for thousands of years. However, recent intensification of interior Alaska's fire regime, particularly deeper burning of the soil organic layer, is leading to shifts to deciduous dominated successional pathways, resulting in many socioecological consequences. Both fuel load quantity and quality (or “burnability”) influence black spruce plant communities' potential to burn. Even relatively low fuel loads, such as those seen in black spruce forest understory,...

Mangrove forest in the Mekong Delta plays important roles in protecting coasts from soil erosion and strong waves, supplying seafood, and accumulating carbon. Despite these benefits, mangroves have been and continue to be severely damaged by the impacts of natural and socioeconomic activities. In recent years, large areas of mangrove forest have been restored through planting and other various management actions. In this study, we analyzed high-resolution WorldView-2 images to quantify changes in the mangrove forest in seven coastal provinces (Tien Giang, Ben Tre, Tra Vinh, Soc Trang, Bac...