public void queryTrees() {
		ArrayList<String> oldBlooming = new ArrayList<String>(bloomingNames);
		bloomingNames.clear();
		for(Tree tree : observedTrees){
			if(tree.isFlowering()){
				bloomingNames.add(tree.getName());
			}
		}
		
		if(!bloomingNames.equals(oldBlooming)){
			setChanged();
			notifyObservers(bloomingNames);
			clearChanged();
		}
	}