Q. Are the treehouses you design and build, some of which cost six figures, really for children?

A. I get calls all the time for kids’ treehouses. But I think the adults who are placing the calls are hiding the fact that the treehouse is for them. Some people look at these treehouse books and say, “I want one of those.” Or they’re architecture buffs. They don’t have the skills to create it, but they want it. The people who pick up the phone are dreamer types, but they’re also doer types. Somebody who’s going to spend $200,000 on a treehouse is a go-getter.

Q. Your work stretches the limits of what people may think of as a treehouse. What defines a treehouse for you?

A. My definition of a treehouse has broadened substantially. In the beginning, I thought a tree-supported structure, even a supporting post on the ground, was cheating. To me, that was a stilt house. It’s just being up in the trees that now defines a treehouse. If you want to be in a stilt house among the trees, is it a treehouse? Sure. It’s all about sharing in the energy of the tree. However you do that is fair game.

Q. You practice an ephemeral architecture. Have you ever lost a treehouse to bad weather?

A. One of the biggest we ever built was in San Diego County, and the owner lost it in the wildfires. Seven oak trees were involved, and the owner said that after the wildfire, you couldn’t fit the ashes in a bottle. It was that gone.