退耕还林； 经济发展； 河北省； 系统动力学。

Grain for forest; economic development ; Hebei province ; SD.

退耕还林（草）综合效益评价指标体系的构建是退耕还林（草）工程效应评价的一个重要环节。

Establishment of the assessment index system of the returning farmland to forest project's multi-effect of Loess Plateau is a important part of the ecological effect assessment.

我们持续大规模开展退耕还林和植树造林，大力增加森林碳汇。

We have continued with the large-scale endeavor to return to farmland to forest and expand a forestation, and made vigorous effort to increase forest carbon sink.

有个“退耕还林”的国家政策，许诺只要农民退还土地造林，就能每年给以补助。

One national program called for farmers to hand over land for reforestation in exchange for annual payments.