Bioenergy and Biomass

Our national forests are so overcrowded that the growth of many trees is suppressed. Initial research has shown that small-diameter (suppressed-growth) trees have narrower annual rings, more uniform fiber cell structure within the rings, and a higher volume of mature wood. Ironically, due to a number of economic factors, availability of pulpwood from public and private lands in the western United States is diminishing, and the pulp and paper industry has become increasingly reliant on availability of residuals from sawmill operations.

Pulping trials undertaken by Forest Products Laboratory in an industrial pilot-scale facility showed that the characteristics of suppressed-growth trees improve pulp properties in the production of paper. Furthermore, less refining energy was required to produce pulp from forest thinnings than from conventional wood supplies. Results of this work also showed that lumber produced from forest thinnings meets or exceeds the sawmill specification.

Cooperative research involving Forest Products Laboratory and industry showed that log home manufacturing provides a high-value use for logs cut from standing dead trees killed by insects and wildfires and is an excellent source of local employment.

Forest Products Laboratory scientists and partners analyzed small-diameter Douglas-fir and ponderosa pine round wood posts to determine possible guardrail system designs to utilize salvaged logs. Two full-scale guardrail systems were constructed and successfully crash tested, demonstrating the feasibility of these materials for strong guard rail posts. Forest Products Laboratory has also studied mechanically graded lodgepole pine logs for use in building cable suspension bridges. Results provided two options for determining bending strength properties for design of such structures.

Engineered wood composites are a classic high-value, large-volume use for small-diameter trees and underutilized species. Forest Products Laboratory research has developed new engineered composite products and process technologies to manufacture them. This work has shown that suppressed-growth, small-diameter trees from overstocked fire-prone forests can be used to offset costs associated with hazardous-fuels removals.

Forest Products Laboratory led a project with other Forest Service research stations (North Central, Southern, Rocky Mountain, and Pacific Northwest Research Stations) that produced FTE 3.0, a web tool using data from the Forest Service's Forest Inventory and Analysis Program to identify locations in Western states (such as around a particular community) where utilization of biomass from hazardous fuel thinnings can cover costs of treatments.

As the environmental and ecological problems related to the incursion of invasive species into native ecosystems have become more prevalent, the economic concerns about removing the invasives have become more pressing. One method to help offset the sizable harvesting and natural-rangeland restoration costs is to develop value-added biocomposite products that use these invasive species. Forest Products Laboratory has investigated using two especially problematic invasive species, salt cedar (Tamarisk ramosissima) and Utah juniper (Juniperus osteosperma), for use as fillers in biofiber-polymer composites.

The Forest Products Laboratory conducted a study investigating the use of small-diameter ponderosa pine lumber in glued-laminated (glulam) timber members. The objective of this work was to develop an efficient glulam combination utilizing small-diameter ponderosa pine for all laminations. The experimental results suggested that the allowable properties of the glulam combinations using two separate lamination grades were generally higher than the currently available single-grade combination in the glulam standard.

These are but some of the examples of how utilization Research and Development (R&D) has been finding cost-effective uses of the low-valued forest biomass that must be removed from the Nation's forests to restore their health and condition. Forest Products Laboratory, Research and Development, work is focused on creating new, improved technologies to economically use fuel-reduction biomass in bioenergy, solid sawn wood, composites, and wood fiber products needed by the public.

Because of the large volumes of material available, specific research projects develop the science, technology, and economic information needed for cost-effective use of small-diameter trees and forest thinnings as a raw material feedstock in the high-volume commodity uses of wood (dimensional lumber, engineered wood, composites, and pulp, paper and paperboard). In addition, research is assessing the potential of using this currently unmerchantable material to provide unique product properties and use as a feedstock in the emerging end use of forest biomass to energy (space heating, industrial process steam production, liquid transportation fuels, syngas, and chemical feedstock). In addition to hazardous fuels reduction, these R&D activities contribute to expanding markets for forest products, providing sustainable benefits to the American public, and restoring, enhancing, and sustaining the Nation's forests.