A new type of Taiji honeycomb structure bonded outside with wood-based laminates was characterized from a mechanical standpoint. Both theoretical and experimental methods were employed to analyze comprehensively the deformation behavior and failure mechanism under a three-point bending test. The analytical analysis reveals that a Taiji honeycomb has 3.5 times higher strength in compression and 3.44 times higher strength in shear compared with a traditional hexagonal honeycomb. Considering the strength-weight issue, the novel structure also displays an increase in compression strength of 1.75 times and shear strength of 1.72 times. Under a three-point bending test, indentation and core shear failure played the dominant role for the total failure of a wooden sandwich with Taiji honeycomb core. Typical face yield was not observed due to limited thickness-span ratio of specimens. Large spans weaken the loading level due to the contribution of global bending stress in the compressive skin to indentation failure. A set of analytical equations between mechanical properties and key structure parameters were developed to accurately predict the threshold stresses corresponding to the onset of those deformation events, which offer critical new knowledge for the rational structure design of wooden sandwich composites.

Low-grade yellow-poplar (Liriodendron tulipifera) graded No. 2 Common, and No. 3 Common (National Hardwood Lumber Association - NHLA rules) is mainly used by the industry to produce wood pallets. Cross-laminated timber (CLT) panels are options to diversify the usage and increase the value of this material. Therefore, the objective of this study was to produce CLT panels from a population of NHLA graded No. 2A, No. 2B, No. 3A, and No. 3B lumber and to evaluate whether the panel properties meet the bending criteria (major strength direction) and adhesive bond requirements listed for “V” type CLT in ANSI/APA PRG 320-2019 (2020) using Northeastern Lumber Association Manufacturers No. 2 and No. 3 in longitudinal and transverse layers, respectively. Ten panels were produced to evaluate the bond quality and mechanical properties. The bond test results showed average delamination under 5 percent and were more frequent in the central areas of the panel than in the outer panel areas. The results from testing showed that the calculated allowable stress-design bending-strength (major direction) value for the yellow-poplar CLT panels was 1,718 psi (11.84 MPa), which corresponds to a value 90 percent higher than V1 (900 psi, 6.20 MPa) layups. Modulus of elasticity (MOE; major direction) was comparable to V2 and V3, with an average MOE of 1.39 by 10⁶ psi (9,584 MPa). Based on these findings, the study indicated the potential for using low-grade yellow-poplar lumber to produce CLT panels. However, more research is needed to evaluate other mechanical properties in both the major and minor axis.

The Central Appalachian region, where family forest landowners (FFLs) control much of the carbon sequestration potential, holds the potential for forest-based climate solutions. Despite this, participation in carbon offset programs remains low, largely due to the disconnect between small landowner needs and program structure. This study examines FFL preferences for carbon programs in Central Appalachia. Utilizing a panel-data mixed logit model, we evaluated the effects of contract length, payment amount, harvest requirements, and program administration on participation decisions. Our results indicate that higher payments significantly increase program participation. Furthermore, contract lengths of at least 15 years and restrictive harvests negatively influence program participation. Program administration played a significant role, with government-administered programs being less preferred, with odds 48% lower than privately administered programs. Landowner characteristics such as carbon-oriented ownership, education, and income also influence participation. The willingness-to-accept analysis shows high compensation demands for less favorable terms: $107–$397/ha/year for longer contracts and $104–$173/ha/year for harvest restrictions. Additionally, landowners require an extra $66/ha/year for government administration. The findings underscore the importance of designing carbon offset programs that are flexible, offer adequate compensation, and foster trust, while aligning with landowners’ management objectives.

Arborists maintain trees in landscapes where failure can cause damage to infrastructure. Codominant branch unions are considered less stable than lateral branch unions. Previous research has found that unions can be considered codominant when aspect ratio is greater than 0.70 when included bark is present, yet it remains unclear if this threshold is reasonable in the absences of included bark. We utilized digital image correlation to measure strain (deformation) and separation angle to failure to better understand how mechanical loads move through Acer rubrum L. (red maple) branch unions. Strain was found to be higher in the branch regions in limb failure and ball and socket failure modes and strain was greater in the branch protection zone regions of imbedded and flat failures. Strain at failure was found to decrease with increasing aspect ratio, plateauing beyond aspect ratios of 0.83. In the absence of included bark, red maple branch unions appear to become codominant at aspect ratio of 0.83. We recommend that arborists should proactively manage to keep aspect ratios lower than 0.60 and consider mitigation options as aspect ratios approach 0.70.

Diplodia pinea is a fungal pathogen that causes Diplodia shoot blight in pines and is widely spread in red pine (Pinus resinosa) and jack pine (Pinus banksiana) forests in Michigan. The objective of this study was to examine whether infection with D. pinea compromises wood quality in pine stands. Acoustic data was collected using an acoustic tomographer from the stem region at breast height (1.3 m) of red pine and jack pine trees across two categories of forest health condition (control vs. Diplodia-affected), in two latitudinal regions (Lower Peninsula vs. Upper Peninsula), and two levels of initial stand density (low vs. high). The acoustic data was used to infer the wood quality (i.e., density) in these two tree species since material of higher density generally has higher sound velocity rates. Red pine had significantly higher wood quality (i.e., higher sound velocities) in the Upper Peninsula region compared to the Lower Peninsula region. Within each latitudinal region, red pine sound velocities did not show significant differences between forest health condition or initial stand density levels. Jack pine showed no significant differences in sound velocities across the treatment categories. The results indicate that latitudinal region appears to have more impact on red pine wood quality than the influence of forest health condition (presence of Diplodia shoot blight) or initial stand density. All analyzed factors (latitudinal region, forest health condition, and stand density) did not have a significant impact on the wood quality of jack pine.