Thankfully the Smithsonian is now reopened after the government shutdown, but their Walk in the Forest interactive website never closed! This site (Flash-based, so iPad-unfriendly) allows you to take older elementary, middle or high school students on "walks" that serve as scientific investigations. In the process, you can connect the topics of trees and habitats (relevant at many grade levels) to language aspects such as causality and language schema. For example, the first walk has students testing soil texture and pH (schema for describing soil besides color) and linking this to the type of tree that could grow there. This is a perfect website for you to construct graphic organizers for students to use as tracking sheets during use, to help them visually connect the ideas involved. This website would be great to use in conjunction with the app Leafsnap, a visual field guide to trees that can serve as stimuli for descriptive language.