<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1405-0471</journal-id>
<journal-title><![CDATA[Madera y bosques]]></journal-title>
<abbrev-journal-title><![CDATA[Madera bosques]]></abbrev-journal-title>
<issn>1405-0471</issn>
<publisher>
<publisher-name><![CDATA[Instituto de Ecología A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-04712016000100169</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Vertical variation of density, flexural strength and stiffness of Persian silk wood]]></article-title>
<article-title xml:lang="es"><![CDATA[Variación longitudinal en densidad, resistencia a flexión y rigidez de la madera 'de seda' persa]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Kiaei]]></surname>
<given-names><![CDATA[Majid]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Farsi]]></surname>
<given-names><![CDATA[Mohammad]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Islamic Azad University Department of Wood and Paper Engineering Sari Branch]]></institution>
<addr-line><![CDATA[Sari ]]></addr-line>
<country>Iran</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2016</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2016</year>
</pub-date>
<volume>22</volume>
<numero>1</numero>
<fpage>169</fpage>
<lpage>175</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-04712016000100169&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-04712016000100169&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-04712016000100169&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: The aim of this research was to investigate the effects of longitudinal position (stem height) and heart-sapwood on density, modulus of elasticity (MOE) and modulus of rupture (MOR) in bending for Persian silk wood (Albizzia julibrissin). Five normal trees were selected from the Guilan region, Iran. Samples for testing were prepared at four stem height levels (5%, 25%, 50% and 75% of total stem height) in both positions along radial direction (heartwood and sapwood). Analysis of variance results (Anova) indicated that the effects of longitudinal position (stem height) and heartwood-sapwood on the wood density, MOE and MOR were significant. The mean of wood density, MOE and MOR along longitudinal position from base to top decreased with height. The mean of wood density, MOR and MOE in sapwood are lower compared to the corresponding values for heartwood. The relationship between wood density and mechanical strength properties were analyzed by regression models. A positive correlation was found between wood density with MOE and MOR in both heartwood and sapwood.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: El objeto de esta onvestigación fue estudiar los efectos de la posición en dirección longitudinal (altura del tronco) y del duramen y la albura sobre la densidad, el módulo de elasticidad (MOE) y el módulo de ruptura (MOR) en flexión para la madera de 'seda' persa (Albizzia julibrissin). Se recolectaron cinco árboles representativos de la región de Guilan, Irán. Se elaboraron especímenes para prueba a cuatro niveles de la altura del árbol (5%, 25%, 50% y 75% de la altura total del tronco) en ambos tipos de madera en la dirección radial (duramen y albura). Los resultados de los análisis de varianza (Andeva) indicaron que los efectos de la ubicación longitudinal (altura del árbol) y duramen y albura sobre la densidad de la madera, el MOE y el MOR fueron significativos. Los valores promedio de la densidad, MOE y MOR a lo largo de la posición longitudinal de la base a la copa disminuyeron con la altura. Los valores promedio de la densidad, MOR y MOE en albura son menores comparados con los del duramen. La relación entre la densidad de la madera y las propiedades mecánicas se analizaron por medio de modelos de regresión. Se encontró una correlación positive entre la densidad de la madera con MOE y MOR tanto en duramen como en albura.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Albizzia julibrissin]]></kwd>
<kwd lng="en"><![CDATA[modulus of elasticity]]></kwd>
<kwd lng="en"><![CDATA[modulus of rupture]]></kwd>
<kwd lng="en"><![CDATA[radial direction]]></kwd>
<kwd lng="en"><![CDATA[stem height]]></kwd>
<kwd lng="es"><![CDATA[Albizzia julibrissin]]></kwd>
<kwd lng="es"><![CDATA[modulus of elasticity]]></kwd>
<kwd lng="es"><![CDATA[modulus of rupture]]></kwd>
<kwd lng="es"><![CDATA[dirección radial]]></kwd>
<kwd lng="es"><![CDATA[altura del árbol]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[The influence of site and longitudinal position in the tree on the density and strength properties of the wood of Pterygota macrocarpa K. schum]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Ayarkwa]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Ghana Journal of Forestry]]></source>
<year>1998</year>
<volume>6</volume>
<page-range>34-41</page-range></nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[The wood anatomy of eucalypts and papermaking]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bamber]]></surname>
<given-names><![CDATA[R.K.]]></given-names>
</name>
</person-group>
<source><![CDATA[Appita Journal]]></source>
<year>1985</year>
<volume>38</volume>
<page-range>210-6</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Heartwood, its function and formation]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bamber]]></surname>
<given-names><![CDATA[R.K.]]></given-names>
</name>
</person-group>
<source><![CDATA[Wood Science and Technology]]></source>
<year>1976</year>
<volume>10</volume>
<page-range>1-8</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Relationship between heartwood radius early radial growth, tree age, and climate in Pinus canariensis]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Climent]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Chambel]]></surname>
<given-names><![CDATA[M.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Perez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Gil]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Pardoa]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Canadian Journal of Forestry Research]]></source>
<year>2002</year>
<volume>32</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>103-11</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Vertical heartwood variation patterns and prediction of heartwood volume in Pinus canariensis SM]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Climent]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Chambel]]></surname>
<given-names><![CDATA[M.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Gil]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
<name>
<surname><![CDATA[Pardoa]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Forest Ecology and Management]]></source>
<year>2002</year>
<volume>174</volume>
<numero>1-3</numero>
<issue>1-3</issue>
<page-range>203-11</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Proportion and quality of heartwood in Togolese teak (Tectona grandis)]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Dzifa]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Bailleres]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Stoke]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Kokou]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<source><![CDATA[Forest Ecology and Management]]></source>
<year>2004</year>
<volume>189</volume>
<numero>1-3</numero>
<issue>1-3</issue>
<page-range>37-48</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Hillis]]></surname>
<given-names><![CDATA[W.E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Heartwood and tree exudates]]></source>
<year>1987</year>
<publisher-loc><![CDATA[Berlin ]]></publisher-loc>
<publisher-name><![CDATA[Springer-Verlag]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kolzlowski]]></surname>
<given-names><![CDATA[T.T.]]></given-names>
</name>
</person-group>
<source><![CDATA[Growth and development of trees]]></source>
<year>1971</year>
<volume>II</volume>
<page-range>86</page-range><publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Academic Press]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[The within-tree variation in wood density and shrinkage, and their relationship in Populus euramericana]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kord]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Kilashaki]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Kord]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Turkish Agriculture and Forestry]]></source>
<year>2010</year>
<volume>34</volume>
<page-range>121-6</page-range></nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Larson]]></surname>
<given-names><![CDATA[P.R.]]></given-names>
</name>
</person-group>
<source><![CDATA[Wood formation and concept of wood quality]]></source>
<year>1969</year>
<numero>74</numero>
<issue>74</issue>
<publisher-loc><![CDATA[New Haven ]]></publisher-loc>
<publisher-name><![CDATA[Yale University School of Forestry]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Mozaffarian]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[A dictionary of Iranian plants names. Latin, English, Persian]]></source>
<year>1996</year>
<page-range>22</page-range><publisher-name><![CDATA[Farhang Moaser]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Mozaffarian]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Trees and shrubs of Iran]]></source>
<year>2003</year>
<page-range>382</page-range><publisher-loc><![CDATA[Iran ]]></publisher-loc>
<publisher-name><![CDATA[Farhang Moaser publication]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Heartwood and sapwood variation in Eucalyptus globulus Labill. Trees at the end of rotation for pulpwood production]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Morais]]></surname>
<given-names><![CDATA[M.C]]></given-names>
</name>
<name>
<surname><![CDATA[Pereira]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
</person-group>
<source><![CDATA[Annals of Forest Science]]></source>
<year>2007</year>
<volume>64</volume>
<numero>6</numero>
<issue>6</issue>
<page-range>665-71</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Characteristics, chemical composition and utilisation of Albizia julibrissin seed oil]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Nehdi]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
</person-group>
<source><![CDATA[Industrial Crops and Products]]></source>
<year>2011</year>
<volume>33</volume>
<page-range>30-4</page-range></nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Fasarium wilts on native silk trees (Albizia Julibrissin Durz) in the north of Iran, Gorgan]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Panahian]]></surname>
<given-names><![CDATA[G.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Rahnama]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<source><![CDATA[International Journal of Agronomy and Plan Productiont]]></source>
<year>2010</year>
<volume>1</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>1-5</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Panshin]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[de Zeeuw]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Textbook of Wood Technology]]></source>
<year>1980</year>
<edition>4th</edition>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[McGraw-Hill]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Heartwood and sapwood development within maritime pine (Pinus pinaster Ait) stems]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Pinto]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
<name>
<surname><![CDATA[Pereira]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
<name>
<surname><![CDATA[Usenius]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Trees]]></source>
<year>2004</year>
<volume>18</volume>
<page-range>284-94</page-range></nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sabeti]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Trees and shrubs of Iran]]></source>
<year>1975</year>
<page-range>25-6</page-range><publisher-loc><![CDATA[Tehran ]]></publisher-loc>
<publisher-name><![CDATA[University Press]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Sapwood-heartwood proportion related to tree diameter, age, and growth rate in Picea abies]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sellin]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Canadian Journal of Forestry Research]]></source>
<year>1994</year>
<volume>24</volume>
<page-range>1022-8</page-range></nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Wood specific gravity-mechanical property relationship at species level]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zhang]]></surname>
<given-names><![CDATA[S.Y.]]></given-names>
</name>
</person-group>
<source><![CDATA[Wood Science and Technology]]></source>
<year>1997</year>
<volume>31</volume>
<page-range>181-91</page-range></nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zobel]]></surname>
<given-names><![CDATA[B.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Sprague]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Juvenile wood in trees]]></source>
<year>1998</year>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[Springer-Verlag]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zobel]]></surname>
<given-names><![CDATA[B.J.]]></given-names>
</name>
<name>
<surname><![CDATA[van Buijtenen]]></surname>
<given-names><![CDATA[J.P.]]></given-names>
</name>
</person-group>
<source><![CDATA[Wood variation: Its causes and control]]></source>
<year>1989</year>
<publisher-loc><![CDATA[Berlin ]]></publisher-loc>
<publisher-name><![CDATA[Springer-Verlag]]></publisher-name>
</nlm-citation>
</ref>
</ref-list>
</back>
</article>
