The National Arbor Day Foundation has challenged many cities to earn its "Tree City USA" flag by planting and protecting more trees.
国家植树节基金会向许多城市发起挑战，要求它们通过种植和保护更多的树木来赢得那面“美国树城”的旗帜。
2
Not only are they incredible timesavers, the company has partnered with the Arbor Day Foundation to plant a tree for every app purchased.
这款应用不仅极其省时间，公司也与植树节基金会合作，每卖一份应用，就会值一棵树。
3
And knowing that the sound image correlative to the concept tree is "arbor," right, arbor I can think of something like that, something in some way resembling that.