The area circles the tree and this called a girdle . the girdling process weakens the trees . it makes them easier targets for borer and shows if the insects are nearby . efforts to stop the spread of the emerald ash borer include cutting down affected trees . a tree farmer in maryland , for example , recently faced the loss of hundreds of trees . there are worries that the ash trees might disappear unless the invasion is controlled 这个地方是围绕着树一周,这个叫做围绕.围绕的过程削弱了树的抵抗性.这个是它们变成一个更加简单的目标并且如果昆虫靠近的话它就会显示和出来.阻止灰虫传播的努力包括砍伐被感染的树木.一个在马里兰的树农,比如说,最近面临着数百树木的损失.有人担心如果灰虫侵入不得到控制的话灰树会消失
