"If we had stronger computational facilities, we would like to try big data and deeper forest, which is left for future work." and that:
"As a seminar study, we have only explored a little in this direction."
Not saying that the paper has no reason to exist, I think it is generally well written and decision trees certainly deserve attention. If they can do representation learning on high level this is certainly something to look into. But it shouldn't claim to be an alternative to state-of-the-art deep learning if there is no data for this comparison. Everyone can solve MNIST (or even CIFAR).