Funny Trees

We have been spending a lot of time around these particular three trees in our side yard. Nick spent a good two days trimming them and then this past Saturday we spent a good part of the day removing all of the trimmed branches. They have completely left me confused on the wonders of nature. How can one have lost all of it's leaves, one just changing colors, and one still completely green? My best explanation: They are bound and determined to keep me raking for as long as possible...