The vast majority of cat trees are made of cardboard tubing unfortunately. The alternative is something like a kooga tree, similar trees structures available on zooplus. Mine have a 'pot stand' which is huge and is the roots of a java tree.
My cat loves to perch on her 2 story high scratching post and gaze out of the window. After only about 4 months though the perch part has snapped off- which is not surprising really it was only made of giant toilet roll tubes
She loves perching and scratching and as I would rather she didn't perch on the toaster and scratch the quality ikea furnishings, I will have to get her a new one.