Author: Robert A. Megraw
Publisher: Tappi
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 112

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Author:
Publisher:
ISBN:
Category : Juvenile wood
Languages : en
Pages : 48

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Book Description
To satisfy the increasing demand for forest products, much of the future timber supply will be from improved trees grown on managed plantations. This fast-grown resource will tend to be harvested in short age rotations and will contain higher proportions of juvenile wood than that of current harvests. In anticipation of this resource, definitive information is needed on the influence of juvenile wood on lumber properties so that grading rules and the associated allowable design stresses can be modified as needed. This document reports the results of an extensive review of the literature on juvenile wood in southern pines. This report defines and discusses the extent, occurrence, and characteristics of juvenile wood. It reviews the effects that environment and silviculture have on the amount of juvenile wood produced. Finally, the impacts that juvenile wood has on mechanical properties were quantified. The results of this quantification are significant to all producers of fast-grown plantations. Research has clearly shown that juvenile wood will have a detrimental impact on allowable design stresses for visually graded lumber. It is critical that methods are developed to more carefully manage fast-grown plantation wood for its most efficient use. This review should serve as an overall collection of knowledge pertaining to juvenile wood research in southern pines and should help in the decision-making efforts to improve seedling selection techniques and silvicultural practices to maximize the potential for fast-grown plantations of southern pines.

Author: Robert P. Schultz
Publisher: U.S. Government Printing Office
ISBN:
Category : Nature
Languages : en
Pages : 516

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Author: Bruce J. Zobel
Publisher: Springer Science & Business Media
ISBN: 3642721265
Category : Technology & Engineering
Languages : en
Pages : 311

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Book Description
The trend in forestry is toward shorter rotations and more complete utiliza tion of trees. The reasons are: (1) financial pressures to obtain rapid returns on the forestry investment made possible by an earlier harvest; (2) enforced harvest of young plantations to maintain a continuing supply of cellulose for mills where wood shortages are experienced; (3) thinning young plantations, both because they were planted too densely initially and because thinning is done where long rotation quality trees are the forestry goal; (4) more intensive utilization is being done using tops and small diameter trees; and (5) there is interest in using young (juvenile) wood for special products because of its unique characteristics and the development of new technologies. The largest present-day source of conifer juvenile wood is from thinnings of plantations where millions of hectares of pine were planted too densely. Because of the better growth rate resulting from improved silviculture and good genetic stock, plantations will need to be thinned heavily. As a result of this trend, young wood makes up an increasingly larger proportion of the total conifer wood supply each year. Large amounts of juvenile wood from hard woods are also currently available, especially in the tropics and subtropics, because of the fast growth rate of the species used, which results in shorter rotations and ess~ntially all juvenile wood.

Author: William C. Hopkins
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 36

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Author:
Publisher:
ISBN:
Category : Forest management
Languages : en
Pages : 156

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Author: Bruce J. Zobel
Publisher: Springer Science & Business Media
ISBN: 3642795145
Category : Technology & Engineering
Languages : en
Pages : 351

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Book Description
Over the past years, a great deal has been learned about variation in wood prop erties. Genetic control is a major source of variation in most wood properties. Wood is controlled genetically both directly in the developmental or internal pro cesses of wood formation and indirectly by the control of tree form and growth patterns. Emphasis in this book will be on the internal control of wood production by genetics although there will be two chapters dealing with the indirect genetic control of wood, which was covered in detail in the previous book by Zobel and van Buijtenen (1989). The literature on the genetics of wood is very variable, SO'lle quite superficial, on which little reliance can be placed, and some from well-designed and correctly executed research. When suitable, near the end of each chapter, there will be a summary with the authors' interpretation of the most important information in the chapter. The literature on the genetics of wood can be quite controversial. This is to be expected, since both the environment and its interaction with the genotype of the tree can have a major effect on wood properties, especially when trees of similar genotypes are grown under widely divergent conditions. Adding to the confusion, studies frequently have been designed and analyzed quite differently, resulting in conflicting assessments of results.

Author:
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 520

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Book Description
Set includes revised editions of some issues.

Author: John Barnett
Publisher: John Wiley & Sons
ISBN: 1405147814
Category : Science
Languages : en
Pages : 240

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Book Description
Wood is the most versatile raw material available to man. It isburned as fuel, shaped into utensils, used as a structuralengineering material, converted into fibres for paper production,and put to newer uses as a source of industrial chemicals. Its quality results largely from the chemical and physicalstructure of the cell walls of its component fibres, which can bemodified in nature as the tree responds to physical environmentalstresses. Internal stresses can accumulate, which are releasedcatastrophically when the tree is felled, often rendering thetimber useless. The quality of timber as an engineering materialalso depends on the structure of the wood and the way in which ithas developed in the living tree. Tree improvement for quality cannot be carried out without anunderstanding of the biological basis underlying wood formation andstructure. This volume brings together the viewpoints of bothbiologists and physical scientists, covering the spectrum from theformation of wood to its structure and properties, and relatingthese properties to industrial use. This is a volume for researchers and professionals in plantphysiology, molecular biology and biochemistry.

Author: Bruce J. Zobel
Publisher: Springer Science & Business Media
ISBN: 3642740693
Category : Technology & Engineering
Languages : en
Pages : 376

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Book Description
Wood is the usual end product of a forestry operation. Because of its importance, numerous studies have been made relative to wood prop erties, the causes of wood variation, and how best to develop wood for desired products. There is voluminous literature related to these subjects, but it is neither well known nor appreciated by foresters because the publications are often not available or are not well understood by the forester or by those who use the wood. Frequently, the literature is confusing and contradictory, making it difficult for the nonspecialist to use what information is available. In order to produce and use wood efficiently, the variation pat terns within trees, among trees within species, and among species must be understood. This also requires some knowledge of the causes of variation and the effects of different wood properties upon utiliza tion. The information about variation patterns, their causes, and con trol and effect upon the product must be known by the tree grower, the tree breeder, and the tree harvester as well as by those who ultimately convert wood into a final, salable product.