You're looking at a typical metal wing's innards with stringers (small lateral stiffeners made from aluminum angle) riveted to aluminum sheet, and the remnants of wing ribs also attached. The colour is zinc-chromate primer which ranges in colour from bright green (epoxy zinc chromate), to olive drab, to, that that case, yellow/brown.
There is no wood there. If any wood can be found in an airplane like the TU-144, it will be in the interior finishings or panels, or possibly internal bits or fittings that are usually made from plastic, say like a saddle that holds some kind of cylinder in place (in lieu of a plastic or rubber material). But as far as that picture is concerned, you are definetely looking at metal.