Random forest is a machine learning algorithm created and trademarked by Leo Breiman and Adele Cutler. This seems to be a proper noun, however, when I search https://ludwig.guru/ or use Google's https://books.google.com/ngrams/ for common usage most articles favor lowercase. As in, "random forest machine learning," and not "Random Forest machine learning."
When I use "random forest" in a research article, I don't know if I should I capitalize it.