My educated guess is that this is the actual title of the cartoon shown on British television as "Summertime".
But maybe I'm wrong. Foster did direct a cartoon called Summertime for Van Beuren in 1929.
What is certain, however, is that the sequence with trees turning into frolicking silhouettes of naked women certainly pre-dates the Motion Picture Production Code.
And this particular cartoon shown on British TV in the 1990s deals with spring, not summer, with lots of gags at the expense of a Jack Frost figure. It's all set to Offenbach and other classical composers, with Pan and his pipes, dancing flowers and polo-playing centaurs. Quaint, but fast-moving, with some ingenious gags and a really scary Jack Frost.