( ( ( ( Removing ( ( the oldest ) stems ) ) and ) ( thinning ( the ( youngest sprouts ) ) ) ) ( ( ( allows ( sunlight ( and ( air circulation ) ) ) ) ( to ( reach ( ( the center ) ( of ( ( the plant ) ( discouraging diseases ) ) ) ) ) ) ) . ) )
(ROOT (S (S (VP (VP (VBG Removing) (NP (NP (DT the) (JJS oldest)) (SBAR (S (VP (VBZ stems)))))) (CC and) (VP (VBG thinning) (NP (DT the) (JJS youngest) (NNS sprouts))))) (VP (VBZ allows) (NP (NN sunlight) (CC and) (NN air) (NN circulation)) (S (VP (TO to) (VP (VB reach) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (NP (DT the) (NN plant)) (VP (VBG discouraging) (NP (NNS diseases)))))))))) (. .)))
Removing the oldest stems and thinning the youngest sprouts allows sunlight and air circulation to reach the center of the plant discouraging diseases.
(ROOT (S (NP (DT The) (NN stem)) (VP (VBZ is) (NP (NP (DT the) (JJ basic) (NN structure)) (SBAR (WHNP (WDT that)) (S (VP (VBZ holds) (S (NP (NNS plants)) (ADJP (JJ upright))) (, ,) (S (VP (VBG allowing) (NP (NNS plants)) (S (VP (TO to) (VP (VB get) (NP (NP (DT the) (NN sunlight) (CC and) (NN air)) (SBAR (S (NP (PRP they)) (VP (VBP need))))))))))))))) (. .)))