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You are here: NRS Home / Research Programs / Sustaining Forests / Conserve and Enhance Forest Resources / Timber Productivity and Wood Quality
Sustaining Forests

Conserve and Enhance Timber Productivity and Wood Quality

The demand for wood products here in the United States is climbing at twice the rate of population growth. NRS scientists work in many scientific disciplines to develop methods to conserve and enhance forest wood resources. Some work to grow timber trees effectively and efficiently, others to ensure adequate regeneration of seedlings and effective yet non-damaging methods of timber harvest. Additional work focuses on processing and using timber products most efficiently and developing new markets for previously unused forest wood products. NRS research foresters work to find ways that will make significantly more wood available on public and private lands. They work to develop methods to 1) improve genetic material for plantation forestry, 2) improve cost-effectiveness of silvicultural systems, 3) develop more-efficient, environmentally friendly harvesting systems, and 4) find socially acceptable ways to implement high-yield forestry where appropriate. As part of their efforts, many of these groups are providing computer programs and training to assist land managers meet their goals.

Research Studies

[photo:] Hardwood parts for cabinet doors being manufactured in a U.S. woodworking facility. Photo by Urs Buehlmann, Virginia Polytechnic Institute and State University. Used with permission. Industry 4.0
The latest advance, Industry 4.0, involves the rapid digitization of manufacturing, and enhanced automation, including smart factories and data-driven production systems. With ongoing globalization, the wood products industry, including timber products manufacturing will again need to evolve and be open to adapting components of this new paradigm to remain competitive.

[photo:] The forest landscape of the Missouri Ozark Highlands in the Central Hardwood Region is diverse with a mixture of oak/mixed hardwood/shortleaf pine forests and woodlands.The Ecology and Silviculture of Oaks
The Ecology and Silviculture of Oaks brings together a vast body of previously published and original research into a comprehensive 580-page book presenting ecological and silvicultural concepts that can be used to address an array of forest management issues and objectives. The book is designed and intended not so much as a how-to-do-it management manual as it is a source of ideas on how to think about oak forests as responsive ecosystems. 


Crop Tree Management
Crop tree management (CTM) is a widely applicable silvicultural technique used to enhance the performance of individual trees. It offers flexibility in that it can be applied on small or large properties and, with certain modifications, it can be applied as a precommercial or commercial operation. 


Thinning treatments
To apply effective thinning treatments, land managers need answers to several important questions: How do individual trees respond to reduced crowding?  How does thinning affect wood quality and tree vigor?  How does thinning affect wildlife habitat? Do harvest operations associated with thinning damage the residual forest? What are the financial impacts associated with thinning?


Herbicide treatments
Forestry herbicides are a versatile, cost-effective tool that can be used in a variety of ways to help manage forest vegetation.  In mature forests, herbicide treatments can be used to control interfering plants that prevent new seedlings from developing on the forest floor. In young forests, they can be used to reduce competition around selected trees, thus enhancing growth and survival of individual trees that provide wildlife food, wood products, and seed sources for future forests.


Feller-Buncher and Cut-to-Length
The trend towards increased mechanization in forest harvesting is due to the need to meet productivity, cost, safety objectives, and environmental concerns. Using machines to fell, delimb, bunch, and sort trees gives a logging company the potential to be more productive than using crews of hand fellers.


[photo:] The forest landscape of the Missouri Ozark Highlands in the Central Hardwood Region is diverse with a mixture of oak/mixed hardwood/shortleaf pine forests and woodlands.Sustaining Central Hardwood Forests
A number of challenges to sustain central hardwood forests face managers today. For example, it is difficult to sustain the current level of oak stocking in mature forests in many areas, especially on more productive sites. Oak species are often replaced by either more shade-tolerant species such as maples, or by fast growing species such as tulip tree (yellow-poplar) when forests are regenerated either by managed harvesting or natural disturbances. This is a problem in both upland and bottomland forests.


[photo:] Intensively managed pecan sapling with weed control, deer protection, and pruning to maintain central stem.Intensive Management of Hardwood Plantings
In the 1960s the diminishing supply of quality hardwood saw timber, especially black walnut, raised the question of how best to grow hardwoods in plantations to assure future supplies.  At the time, we determined the most promising native hardwood for timber production in intensively managed plantings was black walnut, white ash, and several of the oak species.  


[photo:] Oak decline in the canopy of the Sinkin Experimental Forest, 2003.Oak Decline
Management solutions are urgently needed to cope with the large number of oak trees that are declining and dying in oak-dominated forests.  This problem is referred to as oak decline and has become a chronic problem for the region’s aging oak forests.


[photo:] Swamp white oak 8 years after being planted as a large container seedlings grown by the Root Production Method (RPM®) in a former agricultural crop field along the Missouri River.  Trees were planted with redtop grass to control competition.Restoring Forests in Bottomland Fields
We have identified several promising practices and seedling types that can be used to successfully restore oak to future bottomland forests when bringing marginal agricultural lands back into forest production.


[photo:] A group selection opening in the Management Strategies Study on the Kane Experimental ForestContrasting Silvicultural Systems
In order to provide science-based guidance to society and landowners to support their silvicultural decisions, scientists must implement replicated examples of different silvicultural treatments and assess their outcomes. Such research often requires decades of measurements, and outcomes and outputs vary by forest type and ecoregion. Results can also be complicated by interactions among silvicultural systems and treatments and other landscape scale disturbances.


[image:] The Tionesta Research Natural Area as seen in 2004 with beech mortality over 40%. The mortality reached 52% in 2006 and shows no sign of diminishing (see figure below). The foreground is an old Tornado swath of a much younger age class.Impacts of Beech Bark Disease
In 2000, very high populations of the beech scale (Cryptococcus fagisuga) were observed when ground-truthing these areas of discoloration on the Tionesta Scenic and Research Natural Area. In anticipation of mortality, a small number of American beech trees were selected for continued monitoring. These trees were selected to mirror existing long term BBD monitoring plots elsewhere in its range. With beech mortality reaching 52% in 5 years it became obvious that the impact of BBD on old growth American beech-eastern hemlock forest required a more in-depth evaluation.


[image:] Graph shows relation of basal area, umber of trees, and average tree diameter to stocking percentage for upland central hardwoods.Thinning in Mixed Hardwood Forests
Very little was known about managing the growth and quality of hardwood forests in the east as the second- and third-growth forests were developing. Studies of “growth and yield” were established to quantify the growing capacity of these forests.


[image:]  Participants in a SILVAH Training Session conduct a systematic inventory of forest overstory and understory as part of a field exercise in the course. SILVAH - Training Sessions and Computer Software
The SILVAH framework has been adopted by many public and private forest management agencies, and many depend upon the decision-support software to analyze inventory data and recommend prescriptions.  Initially developed for Allegheny hardwood forests, much of the focus in recent years has been expanding the SILVAH framework to incorporate recommendations for sustaining the oak component of mixed oak forests. 


SILVAH turns 50
In 2017, the Northern Research Station is celebrating 50 years of silviculture research in Allegheny Hardwood and mixed oak forests in Pennsylvania. The comprehensive suite of studies, including work on basic silviculture; forest harvesting practices; deer-forest interactions; herbicide, fencing, and fertilization; natural and human disturbances; and prescribed fire has always had one overall goal: to promote regeneration and sustainability of forest resources.


[image:] Primary, secondary, and tertiary impacts of deer on forest understory communitiesDeer Impacts: Primary, Secondary (Interfering Plants), Tertiary (Faciltated Seed Predation)
Overabundant white-tailed deer (Odocoileus virginianus) herds have been shown to be a key determinant of understory plant species composition in  many parts of eastern North America over the last century.   The primary, direct effect of chronic overbrowsing is the reduction in growth and survival of browse-intolerant plant species which ultimately shifts species composition towards a few highly browse-tolerant or unpalatable species.  Such shifts in plant dominance patterns may secondarily result in altered plant-plant competitive dynamics in forests understories.  Finally, through modification of plant composition and structure, deer overbrowsing may also exert indirect effects on the habitat and foraging patterns of other animal species.


[image:] Shows the Racoon Ecological Management Area (Thin and Burn treatment) in 2000, before thinning and two burns, for 'competitiveness' for oaks and hickories.Landscape-level Effects of Thinning and Burning
Oak regeneration continues to be a problem in the Central Hardwoods region of the US. In the absence of regular fire (as was common before European settlement and fire regulatory agencies in the ~1920’s), the canopy closes and oak regeneration is often preempted by more shade-tolerant species like maples. The Fire and Fire Surrogates Study (FFS) is aimed to better understand the influence of multiple fires and thinning on oak regeneration. This research is a component of the FFS work in Ohio.


[image:] Partial screenshot of Laser Log Scanner Controller Software showing scanned log with defect detection results.External Hardwood Log Scanning and Internal Defect Feature Prediction
Automatically locating and classifying log defects helps to improve lumber yield, in terms of both volume and quality.  Traditional defect inspection is done by the sawyer’s naked eye within a matter of seconds.  Such visual inspection has a high error rate, and is easily influenced by the operator’s physical and mental condition.  Thus, this has become an active research area where a variety of computerized defect detection and classification systems are being examined by various research groups to assist the sawyer’s decision-making abilities.


[image:] Red oak vaneer log.Determining wood species preferences
Wood, in many senses, is unique among consumer products and has a number of characteristics that set it apart from other products. Some characteristics are common among species and include color, growth rate/ring density (growth rings per inch), pattern of growth rings (grain texture or pattern), and character marks (knots, stains, insect damage, etc.). Understanding consumer preferences of characteristics and species can aid in the marketing of U.S. species, as manufacturers will have the opportunity to use preference knowledge to promote their products.


[Photo:] Butternut tree on research plantationReintroduction of Canker Resistant Butternut
Butternut is a medium-sized tree native to the eastern U.S. that produces a large, tasty nut; unfortunately butternut is threatened by an exotic fungal disease called butternut canker. Through collaboration with local and regional public and private landowners we have identified and propagated over one-hundred butternuts that appear to have improved resistance to butternut canker disease, and we are preparing to characterize their resistance in replicated trials.


[photo:] black cherry blossomsClonal Production of Elite Black Cherry
Black cherry is the only native hardwood species of the genus Prunus that is of high commercial value for timber and sawlog production. In vitro (tissue culture) propagation methods could be the most cost effective way to produce clones of selected, mature, elite black cherry genotypes or genetically improved genotypes.


[photo:] Seed capsules on a female poplar catkin.Breeding and Selecting Poplar for Biofuels, Bioenergy, and Bioproducts
Hybridization of poplars occurs naturally among certain taxonomic sections, as well as from planned breeding efforts. Given that most of the variability of poplars is at the species level, both intra- and inter-specific hybridization have been vital tools for producing progeny that outperform either or both parents for biologically and economically important traits. It is important to refine breeding, testing, and selection protocols so that new, superior poplar genotypes can replace their underperforming counterparts.


[image:]  Propagating probability distributions of stand variablesData Assimilation
Data sampling routinely involves some degree of uncertainty in the measurements, often called noise, which is unpredictable. Likewise, models used to estimate system processes also contain uncertainty, which can come in many forms, not the least of which is their imprecise formulation based on incomplete understanding of the phenomenon being modeled. The question is how best to estimate the state of the system under consideration through time, along with any unknown model parameters, from these (possibly nonlinear) noisy model predictions and incoming measurements.


[image:] Stochastic stocking chartOptimal Stocking
Foresters use management guides as aids to adjust the stocking of forest stands under management. Typically in uneven-aged forests, foresters manage to some target negative exponential distribution model of the stand diameter distribution. However, mathematical optimization methods provide a better approach to the management of uneven-aged stands, allowing the determination of an optimal diameter distribution based on underlying growth models, given some target objective and sustainability constraints. Optimal uneven-aged stocking guide development is an area of research that is critical to the optimal management of uneven-aged forest stands, and can be used in adaptive management.


[photo:] Photo shows regeneration of multiple speciesRegeneration of Northern and Allegheny Hardwoods
The Allegheny hardwood forest type is a variant of the northern hardwood type consisting primarily of black cherry, red maple, sugar maple and American beech. Associated species include white ash, yellow‑poplar, black birch, yellow birch, cucumber magnolia and hemlock. Black cherry and the maples usually dominate stands in Pennsylvania and southward; white ash and sugar maple tend to be more important, and red maple less important, in the New York portion of the range.


Fungi control nutrient availability to trees
Our research focusses on how decay fungi influence nutrient cycling, soil carbon sequestration and its effects on nutrient exchange with tree roots, beneficial mycorrhizal fungi that are needed for nutrient uptake by trees, and the role of mycorrhizal fungi in tree nutrition. Many of these studies are coupled with measurement of forest productivity, and some of them are associated with natural forest disturbances and forestry operations.


[photo:] Moderate-intensity surface fire in mixed-oak forestEcosystem Management Study: Restoration of Mixed-oak Forests with Prescribed Fire
Historically, fire was a frequent disturbance process in the mixed-oak forests of the central hardwoods region. Fire control has altered forest structure and composition. Forests are more dense and the sustainability of oak and hickory dominance is now threatened by an abundance of shade-tolerant and fire sensitive tree species such as red maple, sugar maple, and beech. Prescribed fire has been advocated to promote and sustain open-structured mixed-oak forests and the plants and animals that have adapted to these communities. However, long-term research on fire effects is lacking.


[photo:] Poplar energy crops near the end of a rotation.Comprehensive Database of North American Poplar Research Published from 1989 to 2011
In addition to compiling the information into one interactive location, our objectives are to encourage publication in peer-reviewed journals and to enhance collaborations with partners outside the poplar community. The constraints of the database include: only peer-reviewed manuscripts that are focused on poplars, cottonwoods, aspens, and their hybrids grown as short rotation woody crops, research conducted in North America, and at least one topic area.


[photo:] Redring milkweed (Asclepias variegata), growing in an Ohio mixed-oak forest after repeated prescribed fires.Plant Diversity in Managed Forests
The great majority of plant diversity in forests is contained in the herbaceous layer, comprised of both herbaceous and woody species.  We seek a better understanding of how forest management activities affect plant diversity.  NRS-2 scientists are investigating the direct and indirect effects of timber harvesting, prescribed burning, herbicide application, and deer browsing (alone and in combination) on plant composition and diversity in mixed oak, Allegheny, and Northern Hardwood forests.


[photo:]  Sugar Maple Decline on the unglaciated Allegheny Plateau in northern PennsylvaniaSite, Stress, Nutrition, and Forest Health Interactions
A range of stressors including defoliating insects, pathogens, droughts, inadequate soil base cations, and changing climate have interacted to affect the health and regeneration of selected northern and central hardwood forest species. In the 1980s and 1990s sugar maple dieback and mortality was extensive across the unglaciated Allegheny Plateau in northern Pennsylvania. 


[photo:]  Red maple stem heating experiment.Fire Effects in Eastern Forests
Understanding fire effects requires consideration of the processes by which the effects occur.  We are applying process-based (mechanistic) approaches to modeling fire effects on endangered Indiana bats and fire-caused tree injury and mortality.  Fires pose risks for bats but also provide opportunities for improving bat roosting habitat, our project considers both sides of the problem. 


[image:]  Map of contigous USA - shows locations of FFS sitesFire and Fire Surrogate Treatments: The Central Appalachian Plateau Site
Current forests in many fire-dependent ecosystems of the United States are denser and more spatially uniform, have many more small trees and fewer large trees than did their presettlement counterparts. Causes include fire suppression, past livestock grazing and timber harvests, and changes in land use. The results include a general deterioration in forest ecosystem integrity and the threat of losing important, widespread forest types. Such conditions are prevalent nationally, especially in forests with historically short-interval, low- to moderate-severity fire regimes, such as the upland oak forests of the central hardwoods region.   


[photo:] Damage caused by the butternut cankerSaving the Butternut
The butternut canker disease is killing butternut and threatening the future of this important hardwood species throughout its range in North America.


photo:] Ice storms are a fact of life for northern forestsTree recovery from ice-storm injury
Although ice storms occur throughout much of the northeastern, mid-atlantic, and north central US, the recovery of trees that survive initial breakage had not been documented. A regional ice storm in 1998 in northern New York and New England provided an opportunity to document that recovery.


[photo:] Second generation jack pine provenance tests.Enhanced Adaptation to Climate Change of Conifer Species and Provenances in Northern Forest Ecosystems
Over 12 million trees were distributed from Wisconsin state forest nurseries in 2007. The success of such regeneration programs depends upon the development of adaptation strategies for enhanced ecosystem sustainability under changing climates. There is a need to identify species and seed sources with enhanced adaptation to climate change pressures to ensure biologically and economically sustainable reforestation, afforestation, and gene conservation.


[photo:] Six- to seven-year-old poplar grown for biofuels, bioenergy, and bioproducts.Biofuels, Bioenergy, and Bioproducts from Short Rotation Woody Crops
We are testing the genetics, physiology, and silviculture of poplar crops. Specific areas of interest include quantitative genetic analyses of biomass, rooting, and other important traits from hundreds of genotypes grown throughout the North Central United States, as well as analyses of tree growth regulating mechanisms in the face of varying environments and changing climate. Our silviculture research includes a range of studies from vegetation management to yield trials.


[photo:]   Lake Baikai, Siberia by Eric GustafsonDesigning Pest-Resistant Forest Landscapes: The Importance of Spatial Pattern
Defoliating insects damage millions of acres of forested land annually in the United States.  The balance of evidence suggests forest insect outbreaks today are more damaging than ever because of changes in forest composition and structure induced by fire suppression and post-harvest proliferation of tree species intolerant to herbivory.  Our central hypothesis is that landscape connectivity of acceptable host types increases defoliator population connectivity, altering the dynamics and spatial structure of defoliator populations, and thus increasing forest susceptibility to insect pest damage.   


image: Bulldozer in riparian areaBest management practices
Forests are managed for a wide range of desired outcomes including fiber production, water quality, wildlife habitat and esthetic appeal. NRS scientists are active in developing “best management practices” (aka BMPs) for various specific forest types and location. BMPs are guidelines designed to meet the desired outcomes while protecting and maintaining forest ecosystems for future generations




Last Modified: 09/19/2017