Bosko was Looney Tunes' first character and star...making 39 shorts before moving on the another studio. Considering how insipid and cutesy most of the Bosko cartoons were, his moving to MGM was NOT a bad thing for Looney Tunes. After all, no real personality was developed for the character...he just acted cute and sang and danced.
Here in "The Tree's Knees", after nearly cutting down a tree and seeing it become anthropomorphic, he relents. During most of the rest of the short, he skips about and dances while trees come to life and whine. There really isn't much in the way of plot...a major problem with most of the Bosco films.
Apart from some lovely animation here and there, there's not much to recommend this short unless you want to see Looney Tunes 'borrowing' the Mickey Mouse character...which they did quite a few times. I am actually surprised Walt didn't sue, as the mice clearly looked just like Mickey. Apart from that, it's saccharine and presents a style which was pretty much dead by 1940 because there really wasn't any humor nor story.