I released the code for new regression tree forests method described in "Growing Regression Forests by Classification: Applications to Object Pose Estimation. The European Conference on Computer Vision (ECCV), 2014." The method outperforms various regression methods such as traditional binary regression tree forests as well as Support Vector Regression and Kernel Partial Least Squares Regression. The code is available from here. It is written in matlab.
http://www.kotahara.com/download-k-clusters-regression-forest.html