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Wood Identification and Chemistry' Covers the Physicalproperties and Structural Features of Hardwoods and Softwoods

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Wood Identification and Chemistry' Covers the Physicalproperties and Structural Features of Hardwoods and Softwoods 11 DOCUMENT RESUME ED 031 555 VT 007 853 Woodworking Technology. San Diego State Coll., Calif. Dept. of Industrial Arts. Spons Agency-Office of Education (DHEA Washington, D.C. Pub Date Aug 68 Note-252p.; Materials developed at NDEA Inst. for Advanced Studyin Industrial Arts (San Diego, June 24 -Au9ust 2, 1968). EDRS Price MF -$1.00 He -$13.20 Descriptors-Curriculum Development, *Industrial Arts, Instructional Materials, Learning Activities, Lesson Plans, Lumber Industry, Resource Materials, *Resource Units, Summer Institutes, Teaching Codes, *Units of Study (Sublect Fields), *Woodworking Identifiers-*National Defense Education Act TitleXIInstitute, NDEA TitleXIInstitute, Woodworking Technology SIX teaching units which were developed by the 24 institute participantsare given. "Wood Identification and Chemistry' covers the physicalproperties and structural features of hardwoods and softwoods. "Seasoning" explainsair drying, kiln drying, and seven special lumber seasoning processes. "Researchon Laminates" describes the bending of solid wood and wood laminates, beam lamination, lamination adhesives,. andplasticlaminates."Particleboard:ATeachingUnitexplains particleboard manufacturing and the several classes of particleboard and theiruses. "Lumber Merchandising" outhnes lumber grades andsome wood byproducts. "A Teaching Unitin Physical Testing of Joints, Finishes, Adhesives, and Fasterners" describes tests of four common edge pints, finishes, wood adhesives, and wood screws Each of these units includes a bibhography, glossary, and student exercises (EM) M 55, ...k.",z<ONR; z _: , , . 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NDEA INSTITUTE for Advanced Study. in INDUSTRIAL ARTS * WOODWORKING TECHNOLOGY__ Six Week Session June 24 toAugust 2 in cooperation with U. S. Office of Education as authorisedunder Title XI of the NDEA (as amended) INDUSTRIAL ARTS DEPARTMENT SAN DIEGO STATE COLLEGE , San Diego, California FAgio,1711r., Mr714707 " qr FACULTY Dr. Gerald K.Hanzapr, Director Harold L. Marsters,Assistant Director frank E. Evans,Coordinator STAFF Gudrun Fairchild,Secretary Luther E. Daugherty,lab Assistant David B. Graham,Lab Assistant Harley J. Gasmann,Student Assistant Robert G. Hanlon,Student Assistant Charles J. Printz,Student ASsistant David W. Sykes,Student Assistant PART 3D IPANTS NUEA INST/TUTE IN WOODWORKING TECHNOLOGY ACKER,Robert A. LONG, Oreland, Pennsylvanist Blanchard, Pennsylvania AIIONE, Eugene D. MOORE,Robert J. Wheaton, 121inois Fargo, North Dakota NICER, Ervin G. MURDOCK, Percy Santa Baebara, California Picayune, Mississippi READING, Norman BONAN, Al L. E. ?bntrose, Colorado CauMbuSsOhiO DAVIS, RAY-M. RICHARDSON, Theral B. Tucson, Arizona Salt LakB Citys Utah DIENER, RobertF. ROSSI JamesN. Kansas Clity, _Missouri California SALA, Howard FOLTZ, ADA= W. Northridge, California Denver, Coi-orado FREEMAN, Dorlald B. SEIFERT, Hargy C. Cheyenne, Wytming San Diego, California GADWAH, Neal D. SMITH, Richard N. Hampton, New Hampshire Burlington, Iowa THORSEN, Michael 0. HARLOW, James Frank Abilene, Texas idinonds, Washington JOHNSON, Stanley J. WALKER, Belton L. Crane, Oregon Winter Park, Florida JONES,Benjamti H. WILIAM, A. D. Carlsbad, New Mexico Haynesville, Louisiana Vrorim,,vrt,- ;',; - . -, ', *.; c ,';.;' A TABLE OF CONTENTS : ;- r 1 ; INSTITUTE .DATA 0 . 9 .STAFF 0 # 0 ii .. PICTURE OF PARTICIPANTS AND. STAFF iii .LISTING OF INSTITUTE PARTICIPANTS SECTION I WOOD IDENTIFICATION AND CHEMISTRY SECTION II a. SEASONING SECTION III ari;RESEARCH ON tatmAr.s SECTION IV PkliTICL3BOARD:A Teaching Unit . SECTION' V. - LUKER IERCFAIWIS MG SECTION VI - A TEACHING UNIT IN PHISICAL ISSTING ION aiGe-4,41. *: - V 1,c 1,34 WOOD IDENTIFICATIONAND CHEMISTRY =1101MMIIMINIMMIlli Presented to Dr. G. K. Hammer Mr. H. Marsters Mr. F. Evans San Diego StateCollege In PartialFulfillment of the Requirementsfor the Course298 Wood TechnologyInstitute =11=11M.. by Robert Acker Robert Diener Percy Murdock Richard Smith Summer 1968 TABLE OP CONTENTS PREFACE Page 1 PFYSICAL PROPERTIES OF WOOD Page 2 STRUCTURAL FEATURES OF WOOD Page 6 SOFTWOODS Page 12 HARDWOMS Page 21 THE CHEYISTRY OF WOOD Page 31 WOOD PRESERVATIVES Page 34 BIBLIOGRAFFY Page 38 GLOSSARY (see Teaching Aids) Page 40 TEACHING AIDS Page 40 STUDENT LAB EXPERIENCES Page 48 HANDOUT SHEETS Page 51 , 1. PREFACE Wood identification, amentioned in this paper, should give the reader a better understanding of the identification of many species. In this paper we believe that it is neces- sary for students to have a better understanding of how to identify different species, which will lead to better selec- tion of woods for jobs in everyday life. Identification of wood is comparatively more difficult than identification of the tree that produced it.There are two main procedures for wood identification--by keys and by cards. .The most pronounced the reliable specific difference in the appearances of woods are found in their cellular struc- ture. Color, odor, weight and hardness help in identifying woods, but as a rule such qualities are too variable to be used singly in distinguishing a large number of woods. Hardwood of ring-porous and diffused-porous will be defined with information about general characteristics, such as growth rings, rays, vessels, sapwood, and heartwood. Softwoods can be divided into two groups; the resinous, those species having resin ducts and the nonresinous, those without resin ducts. There are no perfect tools for wood iden- tification. While we have attempted to give an approach to this problem that seems to be good; we feel there is still room for research and study. ' 2. COLOR A KEY TO WOOD IDENTIFICATION Woad comes in a variety of naturalcolors which may range from almost white,as in the sapwood of many species, to the jet black of the heartwoodof black ebony. Color differences may exist, however, in a single sample of wood;as between sapwood and heartwood, earlywood andlatewood, or between ray tissue and the surroundingwood. Heartwood present a wide variation of colors, predominantly brownsof various shades. Sapwood is always lighter. Color characterizes various species,but is a feature difficult to describe with words. Also, it may vary within a species and is subject to change dueto exposure or treatment. Usually, color is estimated visually,but it may also be meas- ured by technicalmeans. The color of wood exposed to the atmosphere frequently darkens; sapwood usuallydarkens mor ; than heartwood. Such changes are generally chemical in nature; they result from oxidation oforganic compounds contained in wood. Change of colormay take place soon after felling trees in the forests or after sawinggreen logs to lumber. The wood of alder quickly changes from whitishor reddish, then fades to a pale brown. The heartwood of black locust turns from light green to dark brown. Douglas-fir becomes reddish. Lorgexpo- sure of light-colored woods to the sun, especially in high eleva- tions, changes their color to brown, whilelong exposure to rain or high humidity changes them to dark gray. pok Dark natural color usually indicates high durability. In F general, color is imparter to wood by extraneousmaterials de- posited mainly in the heartwood. Many of these materials, known also as extractives, are toxic to wood decayingfungi. Their presence is the cause of high durability of woods like redwood, cypress, cedar, oak, black locust, and osage-orange.For the same reason, heartwood of these and other species ismore durable than sapwood, and woods like basswood, willow, andpoplar pos- sess low durability, Light color, however, does not always denote lack of durability. Bald cypress, certain cedars and sassafras are examples. Color-imparting materials may beso abundant in some woods that they can be utilized as dyes. Before the development of synthetic coloring materials. Some dyes were obtained from woods. It is also noteworthy that some woods, suchas black locust, honey locust2 and a number of tropical speciesare fluorescent. Natural coloration in many woods is very attractiveand may be preserved with transparent finishes,or it may be artifi- cally changed by dyeing or bleaching. Color changesmay also be produced by action of water or steam. Oak becomes almost black after prolonged storage under water. European beech is often steamed to darken its color and make it more desirable for the furniture market. Walnut and sweetgum are also treated with steam to darken their sapwood so that it is bet- ter matched with heartwood. (1: 525-527) In inexpensive furniture the nature color of various woods is often imitated by drying less expensive species. Irregular deposition
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