( ( ( Hinder ( recreational activities ) ) ( ( Habitat alterations ) ( may ( have ( ( ( impacts ( on ( fish ( and ( spawning grounds ) ) ) ) ) , ) ( thus ( ( decreasing ( ( fish ( populations Reduction ) ) ( in ( bird population ) ) ) ) ( for ( ( hunting ( Recreational activities ) ) ( like ( ( fishing and ) hunting ) ) ) ) ) ) ) ) ) ) ) ( ( are ( physically ( obstructed 4 ) ) ) . ) )
(ROOT (S (NP (NP (JJ Hinder) (JJ recreational) (NNS activities)) (SBAR (S (NP (NNP Habitat) (NNS alterations)) (VP (MD may) (VP (VB have) (NP (NP (NNS impacts)) (PP (IN on) (NP (NN fish) (CC and) (NN spawning) (NNS grounds))) (, ,) (VP (ADVP (RB thus)) (VBG decreasing) (NP (NP (NN fish) (NNS populations) (NN Reduction)) (PP (IN in) (NP (NN bird) (NN population)))) (PP (IN for) (S (VP (VBG hunting) (NP (JJ Recreational) (NNS activities)) (PP (IN like) (NP (NN fishing) (CC and) (NN hunting))))))))))))) (VP (VBP are) (NP (RB physically) (CD obstructed) (CD 4))) (. .)))
Hinder recreational activities Habitat alterations may have impacts on fish and spawning grounds, thus decreasing fish populations Reduction in bird population for hunting Recreational activities like fishing and hunting are physically obstructed 4.
(ROOT (S (NP (NP (NN Smoking) (NN tobaccowould)) (ADJP (RBS most) (JJ likely))) (VP (VBP have) (NP (NP (DT a) (JJ negative) (NN impact)) (PP (IN on) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT an) (ADJP (JJ individual) (S (VP (TO to) (VP (VB succeed) (PP (IN at) (NP (JJ physical) (NNS activities))) (SBAR (IN because) (S (NP (PRP it)) (NP (PRP it)))))))) (NNP decreases) (NN stamina) (CC and) (JJ cardiovascular) (NN efficiency))))))) (. .)))
Smoking tobaccowould  most likely have a negative impact on the ability of an individual to succeed at physical activities because it it decreases stamina and cardiovascular efficiency.