A cat tree is the one piece of cat furniture that fights hardest for floor space, which is why so many apartment cats don't have one. The trick is that cats don't want floor space. They want height, a surface they're allowed to destroy, and a spot to watch the room from. All three fit in about half a square metre if you choose well.
Go up, not out
Cats measure territory vertically. A narrow tree with two perches at different heights gives a cat more "room" than a wide, low platform. Look for a footprint under 50 x 50 cm and a top perch at roughly counter height, which is where most cats want to sit anyway. Our Blossom Cloud Cat Tree in the Petite Bloom size is about 72 cm tall on a base that tucks into a corner; the Grand Bloom adds a third perch at 96 cm without widening the base.
The scratching surface decides whether it gets used
A tree that is carpet from top to bottom often becomes a tree that gets ignored, because carpet doesn't give cats the resistance they're looking for. Sisal rope or hemp rope on the trunk is what makes a cat choose the tree over the sofa arm. If the tree you love has no rope, add a standalone post beside it; a 60 cm post like the Reversible Scratching Post or the Vintage Bottle Scratching Post takes up less room than a dinner plate.
Use the window
The best perch in a small apartment is usually the window, and it costs no floor space at all. A suction-cup window hammock turns any sunny pane into a lookout, and it comes down in seconds when you need the window back.
Weight is a feature
A light tree wobbles when a cat jumps on it, and a cat that has been wobbled once rarely comes back. Solid wood bases and a tree that feels heavier than it looks are good signs. If you're buying online, check the weight in the listing; under 3 kg for a tree over 70 cm tall is worth a second thought.
Make it look like it belongs
This is the part people skip, then regret. You will look at this object every day. If it reads as pet equipment, it ends up in a corner where the cat ignores it. If it reads as furniture, it goes where the light and the people are, which is exactly where the cat wants to be. That's the whole reason the cat trees we carry look the way they do.