檢視年轮（多年生木本植物茎的横断面上的同心环纹）的原始碼

[[File:年轮 （多年生木本植物茎的横断面上的同心环纹）.jpg|缩略图|[https://image.baidu.com/search/detail?ct=503316480&z=0&ipn=d&word=%E5%B9%B4%E8%BD%AE%20%EF%BC%88%E5%A4%9A%E5%B9%B4%E7%94%9F%E6%9C%A8%E6%9C%AC%E6%A4%8D%E7%89%A9%E8%8C%8E%E7%9A%84%E6%A8%AA%E6%96%AD%E9%9D%A2%E4%B8%8A%E7%9A%84%E5%90%8C%E5%BF%83%E7%8E%AF%E7%BA%B9%EF%BC%89&step_word=&hs=0&pn=11&spn=0&di=3410&pi=0&rn=1&tn=baiduimagedetail&is=0%2C0&istype=0&ie=utf-8&oe=utf-8&in=&cl=2&lm=-1&st=undefined&cs=2736475297%2C1882556434&os=1186649155%2C728583652&simid=3452569034%2C168093243&adpicid=0&lpn=0&ln=325&fr=&fmq=1635757868343_R&fm=&ic=undefined&s=undefined&hd=undefined&latest=undefined&copyright=undefined&se=&sme=&tab=0&width=undefined&height=undefined&face=undefined&ist=&jit=&cg=&bdtype=0&oriquery=&objurl=https%3A%2F%2Fgimg2.baidu.com%2Fimage_search%2Fsrc%3Dhttp%3A%2F%2F5b0988e595225.cdn.sohucs.com%2Fimages%2F20181207%2Fc15ebc533694400881df9c3cb6058b49.jpeg%26refer%3Dhttp%3A%2F%2F5b0988e595225.cdn.sohucs.com%26app%3D2002%26size%3Df9999%2C10000%26q%3Da80%26n%3D0%26g%3D0n%26fmt%3Djpeg%3Fsec%3D1638350226%26t%3D815e2039d471baa3b4d10b2331891179&fromurl=ippr_z2C%24qAzdH3FAzdH3Fooo_z%26e3Bf5i7_z%26e3Bv54AzdH3FwAzdH3Fdba8nldc9_b8cnlc&gsm=9&rpstart=0&rpnum=0&islist=&querylist=&nojc=undefined&dyTabStr=MCwzLDEsNCw3LDYsNSwyLDgsOQ%3D%3D 原图链接][https://www.sohu.com/a/280139254_815395 来自搜狐]]]
'''年轮 （多年生木本植物茎的横断面上的同心环纹）'''树木内的细胞和导管每年重复一次由大到小，材质由松到密的变化，从而就形成了色泽、质地不同的一圈圈环纹。 
多年生木本植物茎的横断面上的同心环纹。常见于温带的乔木与灌木，通常每年一轮。在温带地区年轮界限明显。热带地区由于一年内气候变化不大，年轮就不明显。