( ( Since ( ( ( decreasing ( the pressure ) ) ( on ( a gas ) ) ) ( ( ( increases ( its volume ) ) , ) ( as ( ( the tree ) ( rises ( to ( areas ( of ( decreased pressure ) ) ) ) ) ) ) ) ) ) ( , ( ( the blisters ) ( ( continue ( to inflate ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (S (S (VP (VBG decreasing) (NP (DT the) (NN pressure)) (PP (IN on) (NP (DT a) (NN gas))))) (VP (VBZ increases) (NP (PRP$ its) (NN volume)) (, ,) (SBAR (IN as) (S (NP (DT the) (NN tree)) (VP (VBZ rises) (PP (TO to) (NP (NP (NNS areas)) (PP (IN of) (NP (VBN decreased) (NN pressure))))))))))) (, ,) (NP (DT the) (NNS blisters)) (VP (VBP continue) (S (VP (TO to) (VP (VB inflate))))) (. .)))
Since decreasing the pressure on a gas increases its volume, as the tree rises to areas of decreased pressure, the blisters continue to inflate.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN gas) (NNS particles)) (VP (VB heat) (PRT (RP up))))) (, ,) (NP (NN pressure)) (VP (VBP increase)) (. .)))