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Full-Text Articles in Life Sciences

A Buried Spruce Forest Provides Evidence At The Stand And Landscape Scale For The Effects Of Environment On Vegetation At The Pleistocene/Holocene Boundary, Douglas D. Stokke Feb 2000

A Buried Spruce Forest Provides Evidence At The Stand And Landscape Scale For The Effects Of Environment On Vegetation At The Pleistocene/Holocene Boundary, Douglas D. Stokke

Douglas D. Stokke

Due to a unique set of circumstances, we were able to excavate an entire spruce (Picea) forest in Michigan's Upper Peninsula, USA, which was buried in the early Holocene (9928 ± 133 uncalibrated 14C years bp). Trees ranged from < 5 cm to > 50 cm in diameter, and dominants were approximately 9 m tall. The stand was multi-aged, with a maximum tree age of 145 years. Well-preserved stem cross-sections (n = 140) were recovered and the entire stand was mapped. Stand reconstruction combined with pollen and sediment analysis revealed a pure spruce forest in the sandy lowlands surrounded by hills dominated by pine, oak …


Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek Jan 1997

Processing Small Quantities Of Walnut Logs For Lumber And Craft Items, Douglas D. Stokke, Peter Y. S. Chen, J. W. Van Sambeek

Douglas D. Stokke

Many walnut plantation owners and woodworking hobbyists would like to process small quantities of walnut logs into lumber and discs for furniture and craft items. Various options exist for sawing, drying, and processing small diameter or short logs into lumber and cross-sectional discs. Portable band saws are a safe and inexpensive log breakdown option to commercial headsaw mills. Processing using the saw-dry-rip method will yield higher quantities of usable lumber from small diameter logs than the conventional saw-rip-dry method. Small quantities of lumber and discs can be inexpensively air dried under shelters or open sheds followed by approximately 15 to …


The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps Jan 1997

The Silviculture-Wood Quality Connection In Eastern Black Walnut, Douglas D. Stokke, Bruce E. Cutter, John E. Phelps

Douglas D. Stokke

The known effects of silvicultural practices on eastern black walnut (Juglans nigra L.) wood quality are reviewed. Since desirable quality differs from end user to end user, no specific recommendations are made.


Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan Jan 1997

Risk Analysis Of Black Walnut And Red Oak Plantations, Douglas D. Stokke, Stephen H. Kolison Jr., Jianbang Gan

Douglas D. Stokke

Risks and uncertainties are prevalent in timber production due to the nature and length of the production process. This paper examines the volatility of timber prices and the effects of some economic uncertainties and risks such as fluctuations in timber prices and the interest rate on the economic returns of black walnut and red oak plantations. Historical patterns of timber prices for black walnut and oaks are investigated and compared with those of other timber species and stock price. The sensitivity of economic returns from black walnut and red oak plantations to changes in timber prices and the discount rate …


Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr. Jan 1997

Influence Of Geographic Origin And Soil Properties On Color Of Black Walnut Veneer, Douglas D. Stokke, Edward C. Workman Jr., John E. Phelps, Felix Ponder Jr.

Douglas D. Stokke

Walnut veneer frorn sites in Missouri, Illinois, and Indiana was analyzed for color attributes and chemical properties. Veneer color also was compared to an industry color standard. Soil chemical and physical properties were measured on selected sites in each state. In general, walnut trees grown on soils with equal proportions of sand, silt, and clay have better veneer color attributes than trees grown on soils with high clay I sand or clay I silt ratios.


Variation In Cell Dimensions And Fibril Angle For Two Fertilized Even-Aged Loblolly Pine Plantations, Douglas D. Stokke, Todd F. Shupe, Elvin T. Choong, Mark D. Gibson Jan 1996

Variation In Cell Dimensions And Fibril Angle For Two Fertilized Even-Aged Loblolly Pine Plantations, Douglas D. Stokke, Todd F. Shupe, Elvin T. Choong, Mark D. Gibson

Douglas D. Stokke

Increment core samples were obtained from randomly selected, nine-year-old lohlolly pine (Pinus faeda L.) in two even-aged plantations in Louisiana in order to determine the variation in cell dimensions and fibril angle of the sites. The Homer site is representative of the growing conditions in north Louisiana, and the Bogalusa site is typical of the conditions in southeastern Louisiana. Both sites were subjected to similar site preparation and weed control and were fertilized in the juvenile period. The anatomical properties that were measured include: fiber length, cell-wall thickness, and microfibril angle (MFA). Observations were made in order to compare corewood …


Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps Oct 1995

Variation In Lightness Of White Oak Dimension Stock, Douglas D. Stokke, Anton D. Pugel, John E. Phelps

Douglas D. Stokke

The objectives of this research were to generate a set of sample parameters for the lightness of planed white oak dimension stock, to investigate the effect of grain angle on lightness values, and to determine the level of sampling needed to color match white oak dimension stock on the basis of lightness or darkness as quantified by the parameter L* (psychometric lightness). This information is important when used to determine the feasibility of low-cost portable instruments for evaluating color in an edge-glued hardwood panel production setting. Color measurements were obtained with a portable spectrophotometer interfaced with a notebook computer. The …


Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg Jan 1994

Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg

Douglas D. Stokke

Birdseye grain distortions in sugar maple must be identified to capture the full value of a timber sale throughout the economic range of birdseye's occurrence. Even when relatively common, birdseye veneer typically makes up less than 1 percent of the harvested volume, but may account for one-half of the value of the sale. With prices recently reaching $50,000 per Mbf for prime logs, omission of birdseye (when present) from cruise data could cause significant economic loss for the forest landowner. But figured wood can sometimes be detected in standing timber (Pillow 1955). Field identification of birdseye sugar maple is critical …


Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke Jan 1992

Micro And Macromorphology Of Recycled Fiber And Wood, Douglas D. Stokke

Douglas D. Stokke

Wood is a major industrial raw material, with U.S. consumption approaching that of aluminum, plastics, cement, and steel combined. Partially as a result of the magnitude of wood and wood products in use, these products constitute a substantial portion of the solid waste stream. In order to reduce the amount of wood and wood fiber disposed in landfills, efforts to recycle these materials into useful products such as structural composites are needed. The success of such conversion depends in part on knowledge of the morphological characteristics of various sources of secondary wood and wood fibers, and the influence of wood …


Lignin Distribution In Thermomechanically Pulped Wood Fibers Via X-Ray Microanalysis, Douglas Stokke, Xuerong Wang Jan 1991

Lignin Distribution In Thermomechanically Pulped Wood Fibers Via X-Ray Microanalysis, Douglas Stokke, Xuerong Wang

Douglas D. Stokke

The three major framework organic constituents of the secondary xylem (wood) of trees are cellulose, hemicelluloses, and lignin. Lignin imparts a number of important physical properties to the woody cell wall. In addition, lignin serves as the "cement" which binds cells together, and is the material which must be softened, altered, or removed during pulping processes. The distribution of lignin within pulp cell walls is of importance with respect to use of the pulp fibers. In this study, x-ray analysis was used to investigate lignin distribution in thermomechanically pulped (i.e., pulped with heat and pressure, with no chemical treatment) aspen …


Sem Views Of Oak Wood, Douglas D. Stokke Jan 1986

Sem Views Of Oak Wood, Douglas D. Stokke

Douglas D. Stokke

The anatomical structure of the secondary xylem (wood) of trees varies with location in the tree. The size, shape, and distribution of cell types varies not only between locations (i.e., stem vs. branch vs. root), but also within an annual ring or across annual rings at a given cross-sectional plane.