Pet Zones
Tall Stairway 2?
Crow's Nest

"Come on up." "Its great but it's dark in here." "Go on in you scaredy cat." "Hang on." "Let's call all the other guys." 

This is an 18" dia. hollow tree with 2 limbs and a house. There are three inner levels and also a bottom door entrance.
"Wow, you can really see a long ways off from up here, huh." -"Do you think we'll ever get to go over there?" "The little guy hasn't figured out how to climb up yet."
Crow's Nest
"What are you guys waiting for? Up here is where it's at. "down there? Uncool for cats" "You can do it." "There's plenty of room up here for more."
"Now this is what I call a big top. Two of us can even stretch out up here."

18" Hollow tree with 72" tree in back corner.
"Hey what are you doing on my tree! I'm thinking of coming down there and pushing your fat butt off that branch. So move it"

18" Hollow tree w/ 3 limbs, 4 doors  and an access hole on top.