That is a good number of trees in a backyard. But it's hardly a microclimate. I imagine that I get more cooling from the (considerably larger) trees in my backyard. And it's nothing like the several degrees of cooling you get in a forest.
Further, I don't see what those trees have to do with the article's advice about native plants.
Surburbia might well be wonderful if that sort of backyard were the norm -- if we ditched the whole 19th and 20th century flight from urban agriculture -- I wouldn't mind being able to have a pig or a goat in the backyard, myself. But this article doesn't seem to have anything to do with that topic.