I for one can love this episode and find it completely lovable and cute. It's the original idea of kids protecting trees from people who want to cut it down. The idea was brought up thousands of times, but I like how this episode portrayed it, and how far Lisa would go to protect this certain tree. I thought this episode was really funny, it had some really good 'Simpsons' moments, it was worth watching. I rated it seven out of ten because I don't think it had the classic originality and quality of the other episodes.
For some reason this particular episode was rated 14+ (TV-14, or whatever you call it in the U.S.), I thought of disagreeing on that, or maybe I'll just have to watch the episode again.