( ( ( ( ( Native ( ( insects and ) diseases ) ) , ) droughts ) , ) ( ( ( ( ( windstorms and ) ( wildfire ( periodically ( impact ( forests ( or ( specific ( tree species ) ) ) ) ) ) ) ) , ) ( leaving ( dead ( or ( weakened trees ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Native) (NNS insects) (CC and) (NNS diseases)) (, ,) (NP (NNS droughts)) (, ,)) (VP (VP (VBZ windstorms)) (CC and) (VP (VBP wildfire) (NP (JJ periodically) (NN impact) (NNS forests) (CC or) (JJ specific) (NN tree) (NNS species))) (, ,) (S (VP (VBG leaving) (NP (JJ dead) (CC or) (JJ weakened) (NNS trees))))) (. .)))
Native insects and diseases, droughts, windstorms and wildfire periodically impact forests or specific tree species, leaving dead or weakened trees.
(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)))))) (. .)))