If the weather does not permit you to go outside to do real quadrat sampling why not do this one instead? M and Ms take the place of trees. I think you could also modify this activity for a math class in terms of studying probability. It would create a real-life application for probability.
I have started doing weekly readings with vocabulary because our assessments have changed to ones in which decoding from informational text is an imperative skill. This is my reading and vocabulary for graphing in science. Although graphing is a skill, it is important for students to know the 'language' of graphing so construction is a smooth process. I will be uploading a fun lab-based graphing project where students collect real-life data to graph very soon. :)