Get kids/students to participate in snapping a pic of a leaf any opportunity they get to feed the data into the system. Reward them somehow.

Ask one simple question with each pic take "How many trees of this type would you estimate are in your vacinity, that you can see"

Map those trees all over and compare with climate/weather.

The estimates just increase the size of the circle on the map that shows where those trees live.

Eventually you'll get a very clear idea of what trees thrive/live where.