{"id":10398,"date":"2025-11-03T13:48:54","date_gmt":"2025-11-03T12:48:54","guid":{"rendered":"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/?p=10398"},"modified":"2025-11-20T13:21:02","modified_gmt":"2025-11-20T12:21:02","slug":"la-tardor-a-la-vall-de-boi","status":"publish","type":"post","link":"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/general\/la-tardor-a-la-vall-de-boi\/","title":{"rendered":"La tardor a la Vall de Bo\u00ed, una explosi\u00f3 de colors."},"content":{"rendered":"\n<p>Al camp d\u2019aprenentatge de la vall de Bo\u00ed tenim el privilegi d\u2019estar envoltats d\u2019un frond\u00f3s bosc caducifoli, t\u00edpic dels paisatges pirinencs humits de muntanya mitjana (900-1600m). Quan arriba la tardor, s\u2019observen uns canvis espectaculars de color en les seves fulles, fins que, finalment, cauen. En certs ecosistemes, com ara els tropicals, les fulles dels arbres es tornen grogues i cauen quan el balan\u00e7 d&#8217;aigua esdev\u00e9 desfavorable, aqu\u00ed, en canvi, la caiguda \u00e9s una adaptaci\u00f3 no a la sequera sin\u00f3 a l&#8217;exist\u00e8ncia d&#8217;un per\u00edode relativament fred. El factor principal que detona aquest proc\u00e9s, abans que arribin les primeres gla\u00e7ades, \u00e9s l\u2019escur\u00e7ament del dia i la conseq\u00fcent disminuci\u00f3 d\u2019hores de llum que reben els arbres. En conseq\u00fc\u00e8ncia, tot i que alguns anys les temperatures siguin relativament suaus, el canvi de color es produeix gaireb\u00e9 sempre de mitjana entre la segona i tercera setmanes d&#8217;octubre.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><a href=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"1024\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019-768x1024.jpg\" alt=\"\" class=\"wp-image-10399\" style=\"width:574px;height:auto\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019-768x1024.jpg 768w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019-225x300.jpg 225w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019-1152x1536.jpg 1152w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0019.jpg 1200w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/a><figcaption class=\"wp-element-caption\">Caldes de Bo\u00ed<\/figcaption><\/figure>\n\n\n\n<p><br>La<strong> clorofil\u00b7la<\/strong> \u00e9s un pigment imprescindible per generar mat\u00e8ria org\u00e0nica a les plantes. Aix\u00ed, durant els per\u00edodes de creixement com la primavera i l\u2019estiu, la clorofil\u00b7la \u00e9s el pigment m\u00e9s abundant. A mida que s\u2019acosta la tardor, la producci\u00f3 d\u2019aquest pigment disminueix, i arriba un punt que no \u00e9s contraresta la seva degradaci\u00f3 (\u00e9s una mol\u00e8cula relativament inestable) de manera el pigment present a les fulles i el seu caracter\u00edstic color verd, s\u2019esvaeixen.<br>Els pigments <strong>carotenoides<\/strong> (carotens i xantofil\u00b7les) no es degraden tan r\u00e0pid com la clorofil\u00b7la, i \u00e9s en aquest moment quan el verd de la clorofil\u00b7la deixa d\u2019emmascarar el color d\u2019aquests pigments: els carotenoides absorbeixen els colors blau i blau-verd, aix\u00ed doncs el color que reflecteixen i apareix a la tardor varia del groc a l\u2019ataronjat, depenent de les proporcions de carotenoides que contingui la fulla.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><a href=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"768\" height=\"1024\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020-768x1024.jpg\" alt=\"\" class=\"wp-image-10401\" style=\"width:460px;height:auto\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020-768x1024.jpg 768w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020-225x300.jpg 225w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020-1152x1536.jpg 1152w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0020.jpg 1200w\" sizes=\"auto, (max-width: 768px) 100vw, 768px\" \/><\/a><\/figure>\n\n\n\n<p><br>Quan els carotenoides tamb\u00e9 s\u00f3n destru\u00efts, apareix el color marr\u00f3 que resulta de la oxidaci\u00f3 d\u2019uns elements qu\u00edmics anomenats tanins, com \u00e9s el cas dels roures.<br>I finalment tenim els pigments <strong>antocians<\/strong>, de colors vermells i porpres, que no son fotosint\u00e8tics per\u00f2 s\u00f3n abundants en les flors i fruits que presenten aquests colors, i tamb\u00e9 es troben a les parts vegetatives de totes les plantes en concentracions molt baixes que fan que no siguin perceptibles. Tamb\u00e9 es generen en quantitats a la tardor, proc\u00e9s<br>impulsat la baixada de temperatures i l\u2019augment de concentraci\u00f3 de sucres a les fulles, l\u2019objectiu dels quals encara \u00e9s incert.<br>El color de les fulles de les diferents esp\u00e8cies arb\u00f2ries a la tardor varia de color groc a taronja o vermell depenent de la proporci\u00f3 de carotenoides i antocians a les seves fulles. Finalment, les fulles cauen, aquest moment s\u2019anomena \u201cabscisi\u00f3\u201d.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><a href=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017-1024x768.jpg\" alt=\"\" class=\"wp-image-10400\" style=\"width:576px;height:auto\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017-1024x768.jpg 1024w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017-300x225.jpg 300w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017-768x576.jpg 768w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017-1536x1152.jpg 1536w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/11\/IMG-20251029-WA0017.jpg 1600w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p><br>Les plantes i arbres t\u00edpicament mediterranis no segueixen aquesta din\u00e0mica pel fet que majorit\u00e0riament es tracta d&#8217;esp\u00e8cies de fulla perenne. Molts d&#8217;aquests arbres i arbustos fins i tot aprofiten les pluges de la tardor per tornar a rebrotar i gaudir d&#8217;una &#8220;segona primavera&#8221;.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large is-resized\"><a href=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"724\" src=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018-1024x724.png\" alt=\"\" class=\"wp-image-10245\" style=\"width:833px;height:auto\" srcset=\"https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018-1024x724.png 1024w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018-300x212.png 300w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018-768x543.png 768w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018-1536x1086.png 1536w, https:\/\/serveiseducatius.xtec.cat\/cda-valldeboi\/wp-content\/uploads\/usu1369\/2025\/03\/Chemistry-of-Autumn-Leaves-2018.png 1654w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Al camp d\u2019aprenentatge de la vall de Bo\u00ed tenim el privilegi d\u2019estar envoltats d\u2019un frond\u00f3s bosc caducifoli, t\u00edpic dels paisatges [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":10399,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"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 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