SOLVED. Children's Mystery book. Kids find something in a hollow tree after it's hit by lightning. Read around 1982. > Likes and Comments

Read around 1982, though it had an older feel. A brother and sister love the outdoors and nature, they have a treehouse that they love. A spoiled rich kid moves in next door. They don't get along until they help him when he falls from a tree, then they all become good friends. There's rumor or a mysterious treasure buried somewhere around. In the end of the book, lightning hits the treehouse tree, knocking off a branch and revealing an old hollow which contains some kind of clue.

Pretty sure this is the 1949 YA novel Mystery in the Pirate Oak by Helen Fuller Orton. Your description is spot on.

beichst wrote: "Pretty sure this is the 1949 YA novel Mystery in the Pirate Oak by Helen Fuller Orton. Your description is spot on."

I think that's it! This group never fails. Thanks.

YW. Glad to be able to help. As I said, your detailed and accurate description was key in being able to identify it.