Treesearch

Forest residues, including unmerchantable and small-diameter trees, tops, and limbs, produced during thinning and timber harvest operations can be used to produce renewable bioenergy and bioproducts. The more efficient utilization of forest residues could also help offset the high costs of forest restoration activities, fire hazard treatments, post-harvest activities and forest management in general. Forest residues have long been underutilized and treated as waste materials because of their high collection and transportation costs as well as their low market value. While open burning is...

Human-caused carbon emissions have pushed global atmospheric CO2 concentrations from a pre-industrial level of 280 ppm to over 400 ppm which in turn is forcing the earth’s climate to change due to increased atmospheric trapping of radiant heat. Temperature and precipitation patterns are changing both temporally and physically (snow vs. rain) while intense storm and heat events are exposing forests to new extremes. These changes are directly affecting tree vitality and growth, causing global tree mortality events, as well as influencing fire behavior and burn frequency, and other abiotic...

A solvent-free route was developed to fabricate 100% biobased, renewable, and degradable polylactide (PLA) composites reinforced will ball-milled celluloses. The results show that the original pulp cellulose fibers were modified to partial amorphization through 30-min ball milling. Filling the ball-milled celluloses into PLA increased the tensile modulus for the resultant cellulose/PLA composite materials, while decreased their tensile strength and impact resistance. This method can be used to access the cost-efficient PLA-based composite materials with tunable mechanical properties. The...

This paper is a written summary of the keynote lecture presented at the 13th Annual Meeting of the Northern European Network on Wood Science and Engineering (WSE2017). The lecture summarized work performed at the Forest Products Laboratory (Madison, WI, USA) over the past 10 years related to understanding diffusion through cell walls. The highlighted work includes advances in electrical measurements and synchrotron-based X-ray fluorescence microscopy. The paper also discusses how diffusion is related to many wood damage mechanisms. The ultimate goal of the presented research is to develop...

Several forest inventory techniques utilize approaches that are similar to stereological approaches often applied in microscopy and other fields. Stereology is characterized by the description and estimation of properties of objects based on samples of lower dimension than the object, e.g., 2-dimensional slices from 3-dimensional objects, 1-dimensional probes from 3-dimensional or 2-dimensional objects and dimensionless points from higher dimensional objects. The stereological character of many forest inventory methods was historically developed independently of recognition of a relationshi...

Many invasion hypotheses postulate that introducing species to novel environments allows some organisms to escape population controls within the native range to attain higher abundance in the introduced range. However, introductions may also allow inherently successful species access to new regions where they may flourish without increasing in abundance.

Invasibility is a key indicator of community susceptibility to changes in structure and function. The fluctuating resource hypothesis (FRH) postulates that invasibility is an emergent community property, a manifestation of multiple processes that cannot be reliably predicted by individual community attributes like diversity or productivity. Yet, research has emphasized the role of these individual attributes, with the expectation that diversity should deter invasibility and productivity enhance it. In an effort to explore how these and other factors may influence invasibility, we evaluated...

Nontimber forest species, resources, and products in U.S. forests and rangelands provide a range of ecological, social, cultural, and economic goods and services. This diversity creates challenges and opportunities for management and governance in an era of accelerating climatic variability. Climate variability and change will likely affect forest ecosystems with potentially increasing risks of negative consequences to natural resources and associated social-ecological systems (Ryan and Archer 2008). Drought, insect and disease outbreaks, and fre, as well as extreme events are expected to...

Seasonal time series data from satellites are highly desired by researchers from different fields to study our Earth system. Seasonal time series data contain the temporal aspects of natural phenomena on the land surface, which are extremely helpful for discriminating different land cover types (Zhu and Liu, 2014), monitoring vegetation dynamics (Shen et al., 2011), estimating crop yields (Johnson et al., 2016), assessing environmental threats (Garrity et al., 2013), exploring human-nature interactions (Zhu and Woodcock, 2014a), and revealing ecology-climate feedbacks (Piao et al., 2015).

Propagule size and number often vary by several orders of magnitude among co-occurring plant species. Explaining the maintenance of this variation and understanding how propagule size contributes to coexistence remain a central challenge for community ecologists. The dominant paradigm is that a competition-colonization trade‐off maintains interspecific variation in seed size, but empirical support is limited and other coexistence mechanisms, such as size‐dependent seed predation, have not been examined.