{"id":2175,"date":"2024-11-27T11:50:11","date_gmt":"2024-11-27T10:50:11","guid":{"rendered":"https:\/\/www.scouts-europe.org\/scoutorama\/?p=2175"},"modified":"2025-02-11T12:08:59","modified_gmt":"2025-02-11T11:08:59","slug":"la-croissance-dun-arbre","status":"publish","type":"post","link":"https:\/\/www.scouts-europe.org\/scoutorama\/la-croissance-dun-arbre\/","title":{"rendered":"La croissance d’un arbre"},"content":{"rendered":"\t\t
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La croissance d'un arbre<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Depuis la petite graine jusqu\u2019\u00e0 l\u2019arbre centenaire, l\u2019arbre passe par de multiples phases de croissance\u00a0:<\/p><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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La naissance d\u2019un arbre<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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  • La graine tombe (ici un gland de ch\u00eane) sur le sol dans l\u2019humus ti\u00e8de et humide. Elle y fermente, puis un jour \u00e9clate.<\/li><\/ul>
    • La germination commence, ses r\u00e9serves la nourrissent. Les premi\u00e8res racines apparaissent et pompent l\u2019eau, les sels et les substances nutritives dans le sol.<\/li>
    • La pousse se d\u00e9veloppe, une petite tige s\u2019\u00e9lance vers le ciel.<\/li>
    • A la recherche de la lumi\u00e8re, les feuilles apparaissent. 50 jours apr\u00e8s la germination, le plant a accompli la majeure partie de sa croissance de premi\u00e8re ann\u00e9e. S\u2019il survit \u00e0 l\u2019hiver, il d\u00e9butera sa deuxi\u00e8me ann\u00e9e muni de bourgeons, d\u2019\u00e9corce, et d\u2019un minuscule \u201ctronc\u201d en bois, faisant de lui un v\u00e9ritable arbre miniature.
      Ici un fr\u00eane est n\u00e9 qui p\u00e8sera des tonnes… s\u2019il n\u2019est pas pi\u00e9tin\u00e9\u00a0!<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      Le tronc m\u00e9moire de l\u2019arbre<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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      L\u2019 alternance des cercles clairs (bois de printemps) et des cercles fonc\u00e9s (bois d\u2019\u00e9t\u00e9) qui sont visibles sur une coupe transversale d\u2019un arbre (souche ou grume) te donne des renseignements sur son \u00e2ge et sur certains \u00e9v\u00e8nements qui ont marqu\u00e9 sa vie.<\/p>

      Chaque double cercle (un clair et un fonc\u00e9) correspond \u00e0 un an de la vie de l\u2019arbre.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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      • Les cercles sont r\u00e9guli\u00e8rement espac\u00e9s\u00a0:<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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        • Les cercles sont irr\u00e9guliers.<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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          L\u2019\u00e2ge d\u2019un arbre<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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          La long\u00e9vit\u00e9 d\u2019une esp\u00e8ce d\u2019arbre est l\u2019\u00e2ge moyen auquel meurt l\u2019arbre<\/p>

          \u00a0<\/p>
          Exemples<\/th>Long\u00e9vit\u00e9<\/th><\/tr><\/thead>
          ch\u00eane rouvre\u00a0:<\/td>500 \u00e0 1000 ans<\/td><\/tr>
          sapin\u00a0:<\/td>400 \u00e0 600 ans<\/td><\/tr><\/tbody><\/table>

          \u00a0<\/p>

          La long\u00e9vit\u00e9 foresti\u00e8re d\u2019une esp\u00e8ce d\u2019arbre est l\u2019\u00e2ge auquel il atteint les dimensions et les qualit\u00e9s les plus int\u00e9ressantes \u00e0 son exploitation (apr\u00e8s cet \u00e2ge, la croissance et la production de semences d\u00e9croissent).<\/p>
          Exemples<\/th>Long\u00e9vit\u00e9 foresti\u00e8re<\/th>Diam\u00e8tre du tronc (*)<\/th><\/tr><\/thead>
          ch\u00eane rouvre, ch\u00eane p\u00e9doncul\u00e9, m\u00e9l\u00e8ze<\/td>150 \u00e0 250 ans<\/td>0,5 \u00e0 0,6 m<\/td><\/tr>
          h\u00eatre, \u00e9pic\u00e9a, sapin<\/td>120 \u00e0 150 ans<\/td>0,4 \u00e0 0,5 m<\/td><\/tr>
          pin, bouleau, charme, \u00e9rable, fr\u00eane, merisier<\/td>70 \u00e0 120 ans<\/td>0,3 \u00e0 0,5 m<\/td><\/tr>
          peuplier, saule<\/td>40 \u00e0 70 ans<\/td>0,25 \u00e0 0,4 m<\/td><\/tr><\/tbody><\/table>

          (*) le diam\u00e8tre du tronc est mesur\u00e9 \u00e0 1,3 m du sol<\/p>

          \u00a0<\/p>

          Pour d\u00e9terminer l\u2019\u00e2ge exact d\u2019un arbre, il faut\u00a0:<\/p>

          • conna\u00eetre la date de sa plantation ou<\/li>
          • le couper pour compter les cernes de son tronc.<\/li><\/ul>

            Pour avoir une estimation fiable de l\u2019\u00e2ge d\u2019un arbre, tu peux utiliser les arbres de la m\u00eame esp\u00e8ce et comparer le diam\u00e8tre de l\u2019arbre \u00e0 celui des arbres d\u00e9j\u00e0 coup\u00e9s. Tu peux aussi utiliser les valeurs moyennes suivantes.<\/p>

            \u00a0<\/p>

            Estimation de l\u2019\u00e2ge d\u2019un arbre et de sa hauteur en fonction du diam\u00e8tre de son tronc<\/p>
            Stades de d\u00e9veloppement<\/a><\/th>Diam\u00e8tre du tronc (1)<\/th>Hauteur de l\u2019arbre (2)<\/th>Age de l\u2019arbre<\/th><\/tr><\/thead>
            Semis<\/a><\/td>0 \u00e0 0,02 m<\/td>0 \u00e0 1 m<\/td>1 \u00e0 6 ans<\/td><\/tr>
            Fourr\u00e9<\/a><\/td>0,02 \u00e0 0,03 m<\/td>1 \u00e0 3 m<\/td>6 \u00e0 10 ans<\/td><\/tr>
            Gaulis<\/a><\/td>0,03 \u00e0 0,10 m<\/td>3 \u00e0 8 m<\/td>10 \u00e0 20 ans<\/td><\/tr>
            Bas perchis<\/a><\/td>0,10 \u00e0 0,20 m<\/td>8 \u00e0 15 m<\/td>20 \u00e0 30 ans<\/td><\/tr>
            Haut perchis<\/a><\/td>0,20 \u00e0 0,30 m<\/td>15 \u00e0 20 m<\/td>30 \u00e0 50 ans<\/td><\/tr>
            Jeune futaie<\/a><\/td>0,30 \u00e0 0,45 m<\/td>20 \u00e0 25 m<\/td>50 \u00e0 100 ans<\/td><\/tr>
            Futaie<\/a><\/td>0,45 \u00e0 0,60 m<\/td>25 \u00e0 30 m<\/td>100 \u00e0 150 ans<\/td><\/tr><\/tbody><\/table>

            (1) mesur\u00e9 \u00e0 1,3 m du sol (2) du sol \u00e0 la cime<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

            Depuis la petite graine jusqu\u2019\u00e0 l\u2019arbre centenaire, l\u2019arbre passe par de multiples phases de croissance<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[21,74],"tags":[],"class_list":["post-2175","post","type-post","status-publish","format-standard","hentry","category-connaissance-de-la-nature","category-les-arbres-et-les-fleurs"],"_links":{"self":[{"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/posts\/2175","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/comments?post=2175"}],"version-history":[{"count":10,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/posts\/2175\/revisions"}],"predecessor-version":[{"id":6074,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/posts\/2175\/revisions\/6074"}],"wp:attachment":[{"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/media?parent=2175"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/categories?post=2175"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.scouts-europe.org\/scoutorama\/wp-json\/wp\/v2\/tags?post=2175"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}