Pressure from similar environments on the organisms over time led to these similar analogous features because of the similar environmental conditions for organisms leads to the physical features that are similar in structure and function. Analogous structures are the structures which are similar in appearance in unrelated or different organisms. These structures have similarities because they perform the same job and not because they share common ancestry.
Measure CO2 Levels from around the town to see if the ratio of Oxygen to CO2 is irregular. It's also important to take in factor how much CO2 intake the plantation around them is so you can see what the entire amount is.