a welcome , if downbeat , missive from a forgotten front 
(ROOT (NP (NP (DT a) (ADJP (JJ welcome) (, ,) (IN if) (JJ downbeat) (, ,)) (NN missive)) (PP (IN from) (NP (DT a) (VBN forgotten) (NN front)))))
(ROOT (NP (NP (DT ) (ADJP (JJ ) (, ) (IN ) (JJ ) (, )) (NN )) (PP (IN ) (NP (DT ) (VBN ) (NN )))))