De or het vegetatieontwikkeling?

The correct Dutch article is:

de vegetatieontwikkeling

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

How to use vegetatieontwikkeling

the vegetatieontwikkelingde vegetatieontwikkeling
this vegetatieontwikkelingdeze vegetatieontwikkeling
that vegetatieontwikkelingdie vegetatieontwikkeling
our vegetatieontwikkelingonze vegetatieontwikkeling
your vegetatieontwikkelingjouw vegetatieontwikkeling
every vegetatieontwikkelingelke vegetatieontwikkeling
which vegetatieontwikkeling?welke vegetatieontwikkeling?
a big vegetatieontwikkeling / the big vegetatieontwikkelingeen grote vegetatieontwikkeling, de grote vegetatieontwikkeling