hard maple

基本解释

Press dried rotary cut American Hard Maple veneer, AB grade.
机械干燥旋切美国硬枫木单板AB级。
Soft maple strength than hard maple low about 25%, On colour is hard maple dim, burnish is no hard maple bright;
软枫的强度要比硬枫低25%左右；色彩上较硬枫暗淡，光泽没有硬枫亮；
Exhibit: american hardwood lumber and floorings. species include red oak white oak ash hard maple soft maple hickory cherry basswood beech birch curly soft maple butternut white pine etc.
展品：北美硬木板材，地板等。品种包括红橡，白橡，水曲柳，硬枫，软枫，山核桃木，樱桃木，椴木，山毛榉，桦木，波纹软枫，白胡桃，白松木等。

They seem like the hard rock maple trees often found in that area, nothing can make them move.

It's most common in hard maple, but also occurs in birch, ash and, in rare cases, black walnut.
NPR: Excerpt: 'A Splintered History Of Wood'