Extract State-Based Subtrees from StanfordCoreNLP Analysis Trees

I am using Stanford CoreNLP to get parsing trees and have to extract all nodes and its children for a specific POS speech tag. For example, remove all S tags that are children of SBAR, create a separate subtree for each S tag, remove that S and all children of S. I could extract the S tags in SBAR, but not sure how to prune the original tree to remove S tags, which are children of SBAR. I think I need to use filter and draft but not sure how to use them conditionally. The code I have will extract all S tags, but I want to remove S if it is a child of SBAR and if it has been added to my tree list.

There is also a more efficient way to do this.

public class test {

        public static void main(String[] args)  {
                            String Text= new String("I think that he wants a big Car");
                    StanfordCoreNLP pipeline = getPipeline();
                    getAnnotation(pipeline, Text);
                }



        private static StanfordCoreNLP getPipeline(){
            // creates a StanfordCoreNLP object, with POS tagging, lemmatization, parsing
            Properties props = new Properties();
            props.put("annotators", "tokenize, ssplit, pos, lemma, parse");
            StanfordCoreNLP pipeline = new StanfordCoreNLP(props);
            return pipeline;
        }


        private static void getAnnotation(StanfordCoreNLP pipeline, String sentence ){

                Annotation document = new Annotation(sentence);
                pipeline.annotate(document);
                List<CoreMap> annotations = document.get(SentencesAnnotation.class);
                ArrayList<Tree> list_trees = new ArrayList<Tree>();
                Tree tree=null;
                Tree PrunedTree ;

                Filter<Tree> f = new Filter<Tree>() { public boolean accept(Tree t) { return !
                          t.label().value().equals("S"); } };
                for(CoreMap annotation: annotations) {              

                  // this is the parse tree of the current sentence
                   tree = annotation.get(TreeAnnotation.class);
                  for (Tree subtree : tree) { 
                    if (subtree.label().value().equals("SBAR")) {
                        for (Tree sbartrees : subtree) 
                        {
                            if (sbartrees.label().value().equals("S"))
                                list_trees.add(sbartrees);  
                        }

                    }
                  }
                }

                PrunedTree=tree.prune(f);
        }
}