( ( Periods ( of heat ) ) ( ( ( can significantly ) ( ( worsen ( drought conditions ) ) ( by ( hastening ( evaporation ( of ( water vapor ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Periods)) (PP (IN of) (NP (NN heat)))) (VP (MD can) (ADVP (RB significantly)) (VP (VB worsen) (NP (NN drought) (NNS conditions)) (PP (IN by) (S (VP (VBG hastening) (NP (NP (NN evaporation)) (PP (IN of) (NP (NN water) (NN vapor))))))))) (. .)))
Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapor.
(ROOT (S (SBAR (IN Because) (S (NP (NNS trees)) (VP (VBP add) (NP (NN water) (NN vapor)) (PP (TO to) (NP (NN air)))))) (, ,) (S (VP (VBG cutting) (PRT (RP down)) (NP (NNS forests)))) (VP (VBZ leads) (PP (TO to) (NP (NP (JJR longer) (NNS periods)) (PP (IN of) (NP (NN drought)))))) (. .)))