converting cropland into forestland project

• 退耕还林

converting cropland into forestland project的用法和样例：

例句

1. The program of the converting farmland into forest is a big systems engineering,which involes broad converage, invests much money and has high participation of farmers.
   退耕还林是一项庞大的系统工程，覆盖面广，投资多，农民参与程度高。
2. The rate of converting arable land into forestland is relatively lower compared with grassland.
   还林的比例相对还草较低，目前的还林结构主要是未成林造林地。