{"id":11449,"date":"2020-02-21T13:46:43","date_gmt":"2020-02-21T12:46:43","guid":{"rendered":"http:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/?p=11449"},"modified":"2022-10-07T11:25:58","modified_gmt":"2022-10-07T09:25:58","slug":"els-alzinars","status":"publish","type":"post","link":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/articles-vegetacio\/els-alzinars\/","title":{"rendered":"Els alzinars"},"content":{"rendered":"

En els paisatges naturals un dels factors m\u00e9s determinants en la vegetaci\u00f3 \u00e9s el clima. Catalunya es troba dins la regi\u00f3 mediterr\u00e0nia, que es caracteritza per tenir pluges escasses, estius \u00e0rids i hiverns suaus. Tot i aix\u00f2 el relleu condiciona l’exist\u00e8ncia de diferents varietats clim\u00e0tiques. Aquest fet i al pres\u00e8ncia de diferents s\u00f2l permet una diversitat extraordin\u00e0ria de paisatges.<\/p>\n

Si ens centrem en la regi\u00f3 mediterr\u00e0nia de muntanya baixa, que \u00e9s la que trobem des de nivell del mar fins a una altitud d’entre 500 i 1000 metres i amb influ\u00e8ncia mar\u00edtima, trobem el bosc mediterrani per excel\u00b7l\u00e8ncia (sense voler menystenir les pinedes i sureres): l’alzinar litoral, que \u00e9s la\u00a0 comunitat cient\u00edficament anomenada Quercetum ilicis galloprovinciale<\/em>.<\/p>\n

\"\"<\/a>Els alzinars ocupen una gran extensi\u00f3 a Catalunya, sobretot en zones de pendent mitj\u00e0. Tot i que en general formen taques de mida petita, la connectivitat entre elles \u00e9s elevada.\u00a0Les alteracions provocades per l\u2019home en aquestes regions potencialment favorables pels alzinars han motivat que sovint trobem un estrat alt de pins degut al seu r\u00e0pid creixement. Aquests boscos mixtos de pi blanc (Pinus halepensis<\/em>) i alzina evolucionen de forma natural cap a un alzinar sense pins.<\/p>\n

A les zones m\u00e9s meridionals el clima m\u00e9s \u00e0rid fa dif\u00edcil la vida de l\u2019alzinar, que \u00e9s substitu\u00eft per una mena de bosc baix, la m\u00e0quia amb ullastre, garrofer, garric, llentiscle i margall\u00f3.<\/p>\n

Terra endins, pels efectes de la continentalitat, hi domina el carrascar, amb un sotabosc notablement m\u00e9s pobre. La carrasca \u00e9s una subesp\u00e8cie d\u2019alzina (Quercus ilex rotundifolia<\/em>) amb la fulla m\u00e9s arrodonida i pilositat tamb\u00e9 per l\u2019anvers.<\/p>\n

\"\"<\/a>Per\u00f2 tornem a l\u2019alzinar t\u00edpic, (tamb\u00e9 anomenat alzinar litoral o alzinar amb marfull) amb l\u2019alzina (Quercus ilex ilex<\/em>) com a protagonista. \u00c9s un bosc esponer\u00f3s i exuberant \u00a0que recorda la frondositat dels boscos tropicals i sovint s\u00f3n dif\u00edcilment transitables. Presenta caracter\u00edstiques esclerofil\u00b7les per suportar la sequera estival: fulles perennes, petites i cori\u00e0cies. Els alzinars tenen una estructura for\u00e7a definida: estrat arbori dens, un sotabosc arbustiu ric i amb diferents nivells i un estrat herbaci pobre per la manca de llum. La caracter\u00edstica m\u00e9s singular \u00e9s la pres\u00e8ncia d\u2019un estrat lianoide ben desenvolupat.<\/p>\n

Revisem amb detall aquests estrats:<\/p>\n

L\u2019estrat<\/strong> arbori<\/strong> quan \u00e9s madur \u00e9s dens, continu i ombr\u00edvol sovint no gaire alt (5-12 m d\u2019al\u00e7ada). Eventualment pot haver algun altre arbre acompanyant l\u2019alzina, com \u00e9s el cas del pi blanc (Pinus halepensis<\/em>) o en les contrades m\u00e9s humides el roure cerrioide (Quercus cerrioides<\/em>)<\/p>\n

L\u2019alzina \u00e9s un arbre resistent al fred i que tolera la sequera gr\u00e0cies al seu potent aparell radical pivotant i fulles esclerofil\u00b7les. Forma cap\u00e7ades amples i denses. Les fulles s\u00f3n perennes, el\u00b7l\u00edptiques i amb marge lleugerament dentat i pilositat a l\u2019anvers. Forma penjolls de flors petites i fructifica donant aglans.<\/p>\n

En el sotabosc hi podem diferenciar un estrat arbustiu alt<\/strong> (1,5 \u2013 3 m) format per grans arbustos de port arbori com el marfull (Viburnum timus<\/em>), l\u2019aladern (Rhamnus alaternus<\/em>) i l\u2019aladern fals (Phillyrea latifolia<\/em>), l’arbo\u00e7 (Arbutus unedo<\/em>), el bruc boal (Erica arborea<\/em>) i el llentiscle o mata (Pistacia lentiscus<\/em>).\u00a0 En les contrades m\u00e9s humides apareix l\u2019ar\u00e7 blanc (Crategus monogyna<\/em>) i el sanguinyol (Cornus sanguinea<\/em>), tots dos de fulla caduca. A l\u2019estrat arbustiu baix<\/strong> (fins 1 m aproximadament) s\u2019hi fan el galzeran (Ruscus aculeatus<\/em>), l\u2019esparraguera (Asparagus acutifolius<\/em>). A les obagues trobem tamb\u00e9 el lloreret (Daphne laureola<\/em>).<\/p>\n

Al sotabosc cal afegir la pres\u00e8ncia d\u2019un estrat lianoide<\/strong> ben desenvolupat que forma un conjunt notablement compacte. Hi trobem les seg\u00fcents enfiladisses: l\u2019heura (Hedera<\/em> helix<\/em>) que tamb\u00e9 entapissa el terra, l\u2019ar\u00edtjol (Smilax aspera<\/em>), la rogeta (Rubia<\/em> peregrina<\/em>), el lligabosc (Lonicera implexa<\/em>) o la vidiella o ridorta (Clematis flamula<\/em>).<\/p>\n

L\u2019estrat herbaci<\/strong>, privat de llum, \u00e9s molt pobre i nom\u00e9s trobem alguna falguera com la Falzia negra (Asplenium adiantum-nigrum<\/em>) o la viola boscana (Viola alba<\/em>).<\/p>\n","protected":false},"excerpt":{"rendered":"

En els paisatges naturals un dels factors m\u00e9s determinants en la vegetaci\u00f3 \u00e9s el clima. Catalunya es troba dins la regi\u00f3 mediterr\u00e0nia, que es caracteritza per tenir pluges escasses, estius \u00e0rids i hiverns suaus. Tot i aix\u00f2 el relleu condiciona l’exist\u00e8ncia de diferents varietats clim\u00e0tiques. Aquest fet i al pres\u00e8ncia de diferents s\u00f2l permet una […]<\/p>\n","protected":false},"author":3,"featured_media":11550,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","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":"default","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":[383],"tags":[],"class_list":["post-11449","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles-vegetacio"],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11449","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/comments?post=11449"}],"version-history":[{"count":3,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11449\/revisions"}],"predecessor-version":[{"id":11480,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/posts\/11449\/revisions\/11480"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media\/11550"}],"wp:attachment":[{"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/media?parent=11449"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/categories?post=11449"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/serveiseducatius.xtec.cat\/cda-cansantoi\/wp-json\/wp\/v2\/tags?post=11449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}