After the fire, they reforested the mountain.

大火后，他们在山上重新植林了。

To tackle the erosion problem, a large area of suitable mountains has been reforested .

为了解决侵蚀问题，大面积的适宜荒山已经植树造林。

His theory is that enough people died that farm fields reforested and sucked up carbon dioxide establishing a kind of anti-green-house-gas effect.

他的理论是，由于太多人死亡，农田退化成森林，由此吸收了更多二氧化碳，形成一种“反温室效应”。