( ( Plants ( in ( low elevations ) ) ) ( ( are ( more ( likely ( to ( ( experience ( cold injury ) ) ( since ( ( ( ( warm ( air rises ) ) and ) ( cold air ) ) settles ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Plants)) (PP (IN in) (NP (JJ low) (NNS elevations)))) (VP (VBP are) (ADJP (RBR more) (JJ likely) (S (VP (TO to) (VP (VB experience) (NP (JJ cold) (NN injury)) (SBAR (IN since) (S (NP (NP (JJ warm) (NN air) (NNS rises)) (CC and) (NP (JJ cold) (NN air))) (VP (VBZ settles))))))))) (. .)))
Plants in low elevations are more likely to experience cold injury since warm air rises and cold air settles.
(ROOT (S (NP (NP (DT The) (JJR lower) (NN density)) (PP (IN of) (NP (JJ warm) (NN air)))) (VP (VBZ causes) (S (NP (PRP it)) (VP (TO to) (VP (VB rise) (PP (IN above) (NP (JJ cold) (NN air))))))) (. .)))