铁杉,一类古老的常绿树种,分布于北半球的局部地区,是第三纪孑遗树种。铁杉树形优雅,树冠或如金字塔般傲然耸立、卓然不群,或层层枝叶在通直的树干上水平展开,如同一把把大伞为下层的树木遮风挡雨,或与其他树种如松、冷杉、云杉、枫树一起,形成混交林。在东半球,铁杉分布在东亚 Hemlock, an ancient evergreen species distributed in parts of northern hemisphere, is a Tertiary relic species. The hemlock is elegant in tree shape, proudly crowned like a pyramid or stands like a pyramid, standing outright, or with layers of foliage spreading horizontally on a straight tree trunk, like a tree sheltering large umbrellas, or sheltering with other species Pine, fir, spruce, maple together to form a mixed forest. In the eastern hemisphere, hemlock is distributed in East Asia