So they set about clearing the land for agriculture, setting fire to massive tracts of forest.
( So ( they ( ( ( ( set ( about ( clearing ( ( the land ) ( for agriculture ) ) ) ) ) , ) ( ( setting fire ) ( to ( ( massive tracts ) ( of forest ) ) ) ) ) . ) ) )
(ROOT (S (IN So) (NP (PRP they)) (VP (VBD set) (PP (IN about) (S (VP (VBG clearing) (NP (NP (DT the) (NN land)) (PP (IN for) (NP (NN agriculture))))))) (, ,) (S (VP (VBG setting) (NP (NN fire)) (PP (TO to) (NP (NP (JJ massive) (NNS tracts)) (PP (IN of) (NP (NN forest)))))))) (. .)))
As a result, the land was devastated by erosion.
( ( As ( a result ) ) ( , ( ( the land ) ( ( was ( devastated ( by erosion ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (NP (DT a) (NN result))) (, ,) (NP (DT the) (NN land)) (VP (VBD was) (VP (VBN devastated) (PP (IN by) (NP (NN erosion))))) (. .)))