while (treeItr.hasNext()) {
Tree tree = treeItr.next();
// CoreLabels, with morph analysis in the originalText annotation
List<Label> yield = rawTrees == null ? tree.yield() : rawTreesItr.next().yield();
// Annotated, binarized tree for the tags (labels are usually CategoryWordTag)
List<Label> pretermYield = tree.preTerminalYield();
int yieldLen = yield.size();
for (int i = 0; i < yieldLen; ++i) {
String word = yield.get(i).value();
int wordId = wordIndex.addToIndex(word); // Don't do anything with words