TreeBagger Training, large datasets

I want to train the TreeBagger Classifier with a large dataset (4 mio x 1 array). My PC runs out of memory if I try to do this in one run! Is their a chance to run the Training in a loop? I was wodering if I could first use a subsets of the training data to train the TreeBagger algorithm and update it with the missing subsets. Could I use the results of the first Training-run as some kind of prior for the next?

Thanks, Claire