1、Designation:D553694(Reapproved 2010)Standard Practice forSampling Forest Trees for Determination of Clear WoodProperties1This standard is issued under the fixed designation D5536;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the ye
2、ar of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe everyday use of wood for many different purposes creates a continual need for data on itsmechanical properties.S
3、mall clear specimen testing to characterize a species has historically beenemployed for such property determination,and related methods of test are outlined in Methods D143.Because wood is a biological material,its mechanical properties are subject to considerable naturalvariation.Thus,the results o
4、f tests to evaluate the mechanical properties of a species depend to a greatextent upon how the forest trees are sampled for test material.Ideally,if the results of mechanicalproperty evaluations are to be representative of the forest sampled,probability sampling of materialssuch as outlined in Prac
5、tice E105 must be used.However,true probability sampling of the forest treesfor determination of mechanical properties can be extremely complex and expensive because of thebroad geographic range and topographic conditions under which a tree species grows.In someinstances,direct probability sampling
6、may be impractical,necessitating the need for alternativesampling procedures.2,31.Scope1.1 This practice offers two alternative physical samplingprocedures:cruciform sampling and random sampling.Thechoice of procedure will depend upon the intended use for thetest results,the resources available for
7、sampling and testing,and the availability of existing data on the mechanical proper-ties and specific gravity of the species of interest.1.2 A third procedure,double sampling,is included primar-ily by reference.This procedure applies the results of cruciformor random samples through correlation to i
8、mprove or updateproperty values.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations
9、 prior to use.2.Referenced Documents2.1 ASTM Standards:4D143 Test Methods for Small Clear Specimens of TimberD2555 Practice for Establishing Clear Wood Strength ValuesE105 Practice for Probability Sampling of Materials3.Significance and Use3.1 This practice covers procedures of sampling for obtain-i
10、ng small clear wood specimens which,when tested in accor-dance with Methods D143 and,in conjunction with full-sizeproduct tests,will provide mechanical properties for use inderiving design properties for lumber,panels,poles,houselogs,and other products.3.2 Data obtained by testing specimens sampled
11、in accor-dance with these methods also provide information on theinfluence on mechanical properties of such factors as density,locality of growth,position in cross section,height in the tree,and moisture content.3.3 Cruciform sampling is of principal value when informa-tion is desired on the influen
12、ce on mechanical properties of1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.08 on Forests.Current edition approved May 1,2010.Published July 2010.Originally approvedin 1994.Last previous edition approved in 2004 as D5536 94
13、(2004).DOI:10.1520/D5536-94R10.2Bendtsen,B.A.,Freese,F.,and Ethington,R.L.,“A Forest Sampling Methodfor Wood Strength,”Forest Products Journal,Vol 20,No.11,1970,pp.3847.3Pearson,R.G.,and Williams,E.J.,“A Review of Methods for Sampling ofTimber,”Forest Products Journal,Vol 8,No.9,1958,pp.263268.4For
14、referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Con
15、shohocken,PA 19428-2959.United States1 height in the tree;of age or radial position in the tree;of rateof growth;the change from sapwood to heartwood;therelationships between mechanical properties and factors suchas specific gravity;and making general comparisons betweenspecies for purposes of ratin
16、g or selecting species for specificend-use products.Cruciform sampling does not provide unbi-ased estimates of mean values,percentile or other descriptivestatistics,or a means of associating statistical confidence withestimates of descriptive statistics.3.4 Double sampling is used when it is desired to improveor update existing estimates of mechanical property values thatare the basis for establishing allowable design stresses forstress-graded lumber,plywood,poles and piling,and otherwood produc
