( however ( , ( distribution ( ( is ( ( restricted ( by ( temperatures ( too low ) ) ) ) ( for ( ( ( seed germination ) or ) ( seedling survival ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB however)) (, ,) (NP (NN distribution)) (VP (VBZ is) (VP (VBN restricted) (PP (IN by) (NP (NP (NNS temperatures)) (ADJP (RB too) (JJ low)))) (PP (IN for) (NP (NP (NN seed) (NN germination)) (CC or) (NP (VBG seedling) (NN survival)))))) (. .)))
however, distribution is restricted by temperatures too low for seed germination or seedling survival.
(ROOT (S (NP (NN Seed)) (ADVP (RB dormancy)) (VP (VBZ ensures) (SBAR (IN that) (S (NP (NNS seeds)) (VP (VBP germinate) (ADVP (RB only)) (SBAR (WHADVP (WRB when)) (S (NP (NP (NNS conditions)) (PP (IN for) (NP (JJ seedling) (NN survival)))) (VP (VBP are) (ADJP (JJ optimal))))))))) (. .)))