Treesearch

This study develops the theory of risk-averse importance sampling and explains its potential application to forest inventory estimation through the use of a heuristic simulation. When the risk-producing elements of the landscape are known, a risk-averse sampling strategy can be created that results in fewer samples in high-risk areas. Our simulation shows that for certain high-risk populations, risk-averse importance sampling can be highly effective at reducing both risk to field crew members (requiring only 10% of the plot visits in the riskiest category) and sample variance relative to ...

As the future climate becomes hotter or drier, forests may be exposed to morefrequent or severe droughts. To inform efforts to ensure resilient forests, it is critical to know which forests may be most exposed to future drought andwhere. Longer duration droughts lasting 2–3 years or more are especiallyimportant to quantify because forests are likely to experience impacts. We summarized exposure to 36-month drought for forests across the conterminous United States using the Standardized Precipitation-EvapotranspirationIndex (SPEI) overlaid on forest inventory plot locations. Exposure was quanti...

Hydroxystilbenes are a class of polyphenolic compounds that behave as lignin monomers participating in radical coupling reactions during the lignification. Here, we report the synthesis and characterization of various artificial copolymers of monolignols and hydroxystilbenes, as well as low-molecular-mass compounds, to obtain the mechanistic insights into their incorporation into the lignin polymer. Integrating the hydroxystilbenes, resveratrol and piceatannol, into monolignol polymerization in vitro, using horseradish peroxidase to generate phenolic radicals, produced synthetic lignins [...

The global pandemic, due to SARS-CoV-2 (COVID-19), disrupted global commodity markets and individual consumption patterns. Various COVID-19-related policies were put in place by state and local governments to limit the virus outbreak, which disrupted the production and supply chains of manufacturing industries. The forest sector was not an exception. Using the Time Regression Discontinuity (T-RD) approach, we quantified the effect of various COVID-19 policies on standing timber prices in the Southern United States. We found an overall significant decrease in prices across all timber products (...

The Timber Products Output (TPO) survey is used to determine industrial uses of roundwood, reporting on volumes of roundwood received and residues generated by the primary forest industry by tree species and counties of harvest. This knowledge aids stakeholders in making informed decisions about available forest resources and/or harvest intensity. The widespread use of TPO estimates makes it important to understand the scale and scope of missing data in the survey. This first attempt analyzed respondent-level and question-level nonresponse (RLNR and QLNR, respectively) for Northern and Souther...

Lignin is one of the three structural components of lignocellulosic biomass and the only renewable source for sustainably producing aromatic chemicals. Despite lignin’s promise for targeted valorization to fine chemicals, fuels, and polymer composites, a major roadblock is an ambiguity associated with its molecular structure. Due to the lack of an established molecular structure, all types of computational studies from reaction mechanism to reaction energetics are performed with model lignin compounds. Among several thermochemical conversion techniques, lignin pyrolysis has been an active rese...