People plant willows on the edge of their narrow yards , to be more accurate , corridors .
人们在他们狭窄的院子边，或者更确切地说，走廊边上种植柳树。
A little way off , along the river bank , willows were growing .
稍远的地方，沿河生长着柳树。
But steven strauss , a forest biologist at oregon state university , says that because of the great genetic variation in willows and poplars , genetic modification may not be necessary .
