Growth Stresses in Trees and Related Wood Properties PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
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Book Description
Author: Robert R. Archer
Publisher: Springer Science & Business Media
ISBN: 3662025116
Category : Technology & Engineering
Languages : en
Pages : 251
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Book Description
Although over 40 years have passed since Jacobs (1945) convincingly established the basic radial pattern of residual growth stress in growing trees, yet this phenomenon is still not widely appreciated in wood science and technology circles. This is in spite of the fact that the presence of these stresses of sizeable magnitudes has long been recognized as a primary cause of shakes and splits in logs as well as the warping of lumber sawn in the green condition. The presentation of the subject of growth stresses in trees presents some special problems due to the wide range of specialists who potentially might have an interest in the subject. For example, tree physiologists interested in questions such as the relation of mechanical stress to stem taper and the role of reaction wood and gravity forces in determining tree crown form encounter growth stress models. Silvi culturists interested in the relation ofthinning practices to wood quality find that wood properties are correlated with growth stress levels which are in turn significantly changed by cutting practices. Wood techno logists interested in the relation of residual growth stress gradients in green logs to the dimensional quality of sawn and seasoned lumber are forced to take a more quantitative approach to the effect of growth stresses than might have been the case in the past.
Author: International Union of Forestry Research Organizations. Section 41. Working Groups of Wood Quality, Sawing and Machining, and Tree Chemistry
Publisher:
ISBN:
Category : Lumber
Languages : en
Pages : 478
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Book Description
Author: Claus Mattheck
Publisher: Springer Science & Business Media
ISBN: 3642612199
Category : Technology & Engineering
Languages : en
Pages : 141
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Book Description
Here are two physicists looking over the fence of physics, getting thrilled by the life and growth of trees, taking an altogether different, exciting view of wood: trees produce wood for their own benefit. They do not live for the benefit of man who builds his world using wood as a raw material. Timber is revealed in a different light, and the reader is taught to stop thinking of it in terms of defective beams and boards. Wood only fails as a part of the living tree. To us, the tree and wood biologists, this new definition is a real, inspiring challenge, which is just what Kubler and Mattheck intended it to be. Their answers may seem too simple or little logical to some of us; but the authors are not at a loss for sound and solid arguments. Their field studies prove the incredible, their hypotheses makes us want to get to the bottom of the un proven unbelievable. The authors' answers and arguments are bold and cour ageous. They arouse our curiosity and force us to fathom the facts. It seems as if Kubler and Mattheck wanted to trick us into believing that trees only live and react following mechanical rules and strategies. To tell the truth, that was what I first suspected the authors of: but I was wrong.
Author: Barry Gardiner
Publisher: Springer Science & Business Media
ISBN: 3642108148
Category : Nature
Languages : en
Pages : 281
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Book Description
The book is a fundamental reference source on reaction wood for wood scientists and technologists, plant biologists, silviculturists, forest ecologists, and anyone involved in the growing of trees and the processing of wood. It brings together our current understanding of all aspects of reaction wood, and is the first book to discuss both compression wood and tension wood. Trees produce reaction wood to maintain the vertical orientation of their stems and the optimum angle of each branch. They achieve this by laying down fibre cell walls in which differences in physical and chemical structure from those of normal fibres are expressed as differential stresses across the stem or branch. This process, while of obvious value for the survival of the tree, causes serious problems for the utilisation of timber. Timber derived from trees containing significant amounts of reaction wood is subject to dimensional instability on drying, causing twisting, bending and splitting. It is also difficult to work as timber, and for the pulp and paper industry the cost of removing the increased amount of lignin in compression wood is substantial. This has both practical and economic consequences for industry. Understanding the factors controlling reaction wood formation and its effect on wood structure is therefore fundamental to our understanding of the adaptation of trees to their environment and to the sustainable use of wood. The topics covered include: -Morphology, anatomy and ultrastructure of reaction wood -Cell-wall polymers in reaction wood and their biosynthesis -Changes in tree proteomes during reaction wood formation -The biomechanical action and biological functions of reaction wood - Physical and mechanical properties of reaction wood from the scale of cell walls to planks -The detection and characterisation of compression wood -Effects of reaction wood on the performance of wood and wood-based products - Commercial implications of reaction wood and the influence of forest management on its formation
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: Fredric Paul Riech
Publisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 116
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Book Description
The form of a tree stem and the properties of the wood comprising a stem may be determined by the strength requirements of that stem. If this is true, a tree will react physiologically to stresses which are imposed on a stem. This study was designed to investigate the influence of static bending stress on the growth and wood characteristics of Douglas-fir. Twenty-four nine -year-old Douglas-fir trees from two geographic sources were divided into three treatments. The treatments used were control, low bending stress, and high bending stress. Trees in the low and high treatments were bent with a horizontal force at a point 4. 5 ft. from the base, so that a low and high bending stress, respectively, would be produced in the trees. Bending caused another variable to be introduced into the experiment. That variable was a transverse component of gravity which influenced the low and high treatment trees. The influence of stress and gravity was studied on the diameter, radial, and leader growth of the trees and also on the specific gravity and tracheid length of the wood which was produced. Treatments did not cause a significant change in diameter growth. Radial growth was increased in treatment trees on the side of stems which was under compressive stress. The greatest increase in radial growth occurred in the lower parts of stems from 2. 5 ft. to the base. Leader growth was significantly decreased by the treatments with the greatest decrease in high stress trees. The treatment thus caused a redistribution of wood formation from the higher parts of stems to the lower parts of stems. Stress is thought to be the factor influencing this downward redistribution of wood and causing the increase in radial growth in the lower parts of stems. Specific gravity of wood formed was increased by treatments, but only on the side of sterns containing compressive stress. The greatest increase was at 4. 5 ft. and 2. 5 ft., with only a small increase at the base. The increase in specific gravity was associated with compression wood formation. The increase in specific gravity and associated compression wood formation is believed caused by the transverse component of gravity rather than by any stress influence. Treatments also caused a decrease in tracheid length of wood formed on the sides of stems containing compressive stress. This decrease in tracheid length appeared to be associated with the increase in radial growth which occurred on treatment trees and also with compression wood formation. This study indicates that the function of compression wood is not to resist stresses in trees, but rather possibly to cause a bent or leaning tree to reorient itself in the vertical position. In order to resist stresses in stems, trees produce increased amounts of normal wood. In this way a greater cross sectional area of a stem is available to resist the imposed stresses.
Author: Christoph Richter
Publisher: Springer
ISBN: 3319074229
Category : Nature
Languages : en
Pages : 227
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Book Description
This book offers a broad range of options for technically adapting, handling and processing wood with specific wood characteristics. It starts by discussing wood anatomy and the general factors leading to the formation of wood characteristics. The individual characteristics are then categorized into four groups: 1. Wood characteristics inherent in a tree’s natural growth. 2. Biotically-induced wood characteristics. 3. Abiotically-induced wood characteristics. 4. Types and causes of cracks. New to this English edition is a comparison of wood characteristics found in trees from the boreal, temperate and tropical climate zones. The results show a clear relationship between the effects of sunshine duration, the vertical and horizontal angle of radiation, and crown coverage and the way wood characteristics form. The book addresses all those who work with wood professionally: foresters, gardeners and arborists who want to be able to observe a living tree and identify its internal features and the causes of its prominent wood characteristics. Based on the findings described in this book they can determine how to avoid certain undesirable characteristics, or alternatively how to promote favorable ones as the tree and stand grow. Botanists and dendrologists will learn how wood characteristics arise, and how they affect living trees and wood products. The needs of wood technologists seeking to prevent adverse wood characteristics from influencing wood processing, or to enhance favorable wood characteristics, are also addressed.
Author: Rubin Shmulsky
Publisher: John Wiley & Sons
ISBN: 111942643X
Category : Science
Languages : en
Pages : 504
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Book Description
The updated seventh edition of the classic text on wood science and forestry The seventh edition of Forest Products and Wood Science: An Introduction offers a fully revised and updated review of the forest products industry. This classic text contains a comprehensive review of the subject and presents a thorough understanding of the anatomical and physical nature of wood. The authors emphasize its use as an industrial raw material. Forest Products and Wood Science provides thorough coverage of all aspects of wood science and industry, ranging from tree growth and wood anatomy to a variety of economically important wood products, along with their applications and performance. The text explores global raw materials, the increasing use of wood as a source of energy and chemicals and environmental implications of the use of wood. This edition features new material on structural composites, non-structural composites, durability and protection, pulp and paper, energy and chemicals, and global raw materials. This seventh edition of the classic work: Contains new information on a variety of topics including: structural composites, non-structural composites, durability and protection, pulp and paper, energy and chemicals and global raw materials Includes a fully revised text that meets the changing needs of the forestry, engineering, and wood science academics and professionals Presents material written by authors with broad experience in both the private and academic sectors Written for undergraduate students in forestry, natural resources, engineering, and wood science, as well as forest industry personnel, engineers, wood-based manufacturing and using professionals, the seventh edition of Forest Products and Wood Science updates the classic text that has become an indispensable resource.
Author: Ronald Floyd Luxford
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 62
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Book Description
