Global interest in biomass-based fossil fuel substitutes is increasing, creating needs for new crops and cropping systems that will expand biofuel pr

Stem sinuosity is a deformation that occurs in Douglas-fir and other tree species. Nutritional deficiencies, such as those of copper, zinc, boron, and calcium have been positively associated with increased stem form deformities. The objective of this study was to analyze available soil and total foliar concentrations of sinuous Douglas-fir stands and determine if these data provided insights into the role of nutrients on sinuosity across different sites. Relationships among genetic gain levels across different sites were also assessed to evaluate whether trees selected for growth and form were better at mobilizing and sequestering nutrients in soils or needles. As data collected were multivariate, Mantel test and permutational multivariate analysis of variance (PERMANOVA) were used to study effects of site, genetic gain levels on soil, and foliar nutrients, with ordinations used to visualize trends. The stands were found to be deficient in boron and calcium, and moderately deficient with respect to zinc and nitrogen. Combining foliar data with soil nutrients revealed that there was differential uptake of these nutrients as compared to other more abundant micronutrients. Results of univariate and multivariate analyses showed that site was the most important predictor, which explained variation among soil nutrient concentrations. Genetic gain level was a significant predictor for variation among soil nutrients; however, not significantly for foliar concentrations according to multivariate analyses. Trends in the data indicate that proper genetic selection could reduce sinuosity while also increasing growth. The results of this study support the contention that no one single factor can explain stem sinuosity. It is likely that sinuous growth in trees is caused by a combination of unbalanced nutrient concentrations and metal deficiencies, as were seen in this study, in addition to genetic, environmental, and physiological factors.

Switchgrass intercropped with loblolly pine plantations can provide valuable feedstock for bioenergy production while providing ancillary benefits like controlling competing vegetation and enhancing soil C. Better understanding of the impact of intercropping on pine and switchgrass productivity is required for evaluating the long-term sustainability of this agroforestry system, along with the impacts on soil C dynamics (soil CO₂ efflux; R_S). R_S is the result of root respiration (R_A) and heterotrophic respiration (R_H), which are used to estimate net C ecosystem exchange. We measured R_S in intercropped and monoculture stands of loblolly pine (Pinus taeda L.) and switchgrass (Panicum virgatum L.). The root exclusion core technique was used to estimate R_A and R_H. The results showed pure switchgrass had significantly higher R_S rates (July, August and September), root biomass and length relative to intercropped switchgrass, while there were no significant changes in R_S and roots between intercropped and monoculture loblolly pine stands. A significant decrease in switchgrass root productivity in the intercropped stands versus monoculture stands could account for differences in the observed R_S. The proportions of R_S attributed to R_A in the intercropped stand were 31% and 22% in the summer and fall respectively, indicating that the majority of the R_S was heterotrophic-driven. Ancillary benefits provided by planting switchgrass between unutilized pine rows can be considered unless the goal is to increase switchgrass production.

The private forestry sector faces enormous challenges from complex environmental issues concurrent with societal concerns about intensive forest management and application of silvicultural tools. At the same time, research and development spending and the scientific workforce in the forestry sector has declined. However, the forestry sector has a long history of strategic deployment of science and technology to manage timberlands for many uses, including ecological services. To address science and societal needs from future forests, we describe past successes and potential future innovations of the forestry sector across (1) genetics, (2) silviculture and productivity, (3) harvesting and logging technology, (4) environmental sustainability, and (5) remote sensing and unmanned aerial vehicles. Developing technology is only one component, however; progressing towards sector goals of diversifying the workforce, explicitly valuing research collaborations, and integrating big data across ownerships to guide management decisions will hasten innovation. With the growing complexity of social-ecological-economic challenges, the private forestry sector must enact a tactical approach to addressing stressors with evolving research structures. We offer a vision of a vibrant private forestry sector poised to integrate technological innovation to continue meeting society’s needs through the intersecting effects of climate change and other challenges.