When does It's Arbor Day, Charlie Brown return?

It's Arbor Day, Charlie Brown is the 15th prime-time animated television special based on Charles M. Schulz's comic strip Peanuts. The special premiered on the CBS network on March 16, 1976. The musical score features the final compositions and recorded performances of jazz pianist and composer Vince Guaraldi. This is the first special to feature the character Rerun van Pelt (younger brother to Linus and Lucy)