De or het heidevegetatie?

The correct Dutch article is:

de heidevegetatie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use heidevegetatie

the heidevegetatiede heidevegetatie
this heidevegetatiedeze heidevegetatie
that heidevegetatiedie heidevegetatie
our heidevegetatieonze heidevegetatie
your heidevegetatiejouw heidevegetatie
every heidevegetatieelke heidevegetatie
which heidevegetatie?welke heidevegetatie?
a big heidevegetatie / the big heidevegetatieeen grote heidevegetatie, de grote heidevegetatie