The river-beds are mostly too shallow for anything but flat-bottomed boats.
( ( The river-beds ) ( ( ( are mostly ) ( too ( shallow ( for ( anything ( but ( flat-bottomed boats ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS river-beds)) (VP (VBP are) (ADVP (RB mostly)) (ADJP (RB too) (JJ shallow) (PP (IN for) (NP (NP (NN anything)) (PP (CC but) (NP (JJ flat-bottomed) (NNS boats))))))) (. .)))
The river-beds are deep and can accommodate any kind of boat. 
( ( The river-beds ) ( ( ( ( are deep ) and ) ( can ( accommodate ( ( any kind ) ( of boat ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS river-beds)) (VP (VP (VBP are) (ADJP (JJ deep))) (CC and) (VP (MD can) (VP (VB accommodate) (NP (NP (DT any) (NN kind)) (PP (IN of) (NP (NN boat))))))) (. .)))