De or het houtveredeling?

The correct Dutch article is:

de houtveredeling

Rule Words ending in -ing: almost always de. See the rule

How to use houtveredeling

the houtveredelingde houtveredeling
this houtveredelingdeze houtveredeling
that houtveredelingdie houtveredeling
our houtveredelingonze houtveredeling
your houtveredelingjouw houtveredeling
every houtveredelingelke houtveredeling
which houtveredeling?welke houtveredeling?
a big houtveredeling / the big houtveredelingeen grote houtveredeling, de grote houtveredeling