A significant portion of Wales’ total land area – around 20% (or 4,100sqkm) – is designated as National Park1.
It’s nothing to sniff at, so what happens to national parks after independence (or even before) is an important consideration in terms of land use, planning, tourism and the environment.
1. National Parks Wales. “The National Parks of Wales”. Available at: https://www.nationalparkswales.uk/npw/about/nationalparkswales

Responsibility for National Parks is devolved to Wales and is the responsibility of the Welsh Government and Senedd. So technically this isn’t an independence-related issue – though most of the legacy laws and rules have originated from the UK Parliament.
The broad options (mix and match) might include:
Keep things as they are – We would continue to have national park authorities and continue with the existing designations for protected landscapes: national parks, areas of outstanding natural beauty (AONB), sites of special scientific interest, heritage coast, country parks etc. The three current national parks will, presumably, be joined by a fourth (Clwydian Range) in due course.
National parks should be administered by a regional tier of government rather than dedicated national park authorities – This could be the current corporate joint committees, run along the same lines as a regional transport authority. Based on the Audit Wales report, there would need to be improvements in how representatives from constituent local authorities are selected.
Create an all-Wales stand-alone National Park Service (or equivalent) – National park authorities would be abolished and responsibilities handed to a new stand-alone Welsh Government agency instead (funded from the grants currently provided to the NPAs). Alongside this, a “protected landscapes consent” (similar to listed buildings consent) could be introduced for planning applications within the boundaries of a national park or AONB. The application would be determined by the relevant local authority rather than a national park authority.
Have two designations of protected landscapes – The first, “national park”, would equally balance recreation/tourism and conservation and be much larger in scope, with more emphasis on generating its own income. The second, “nature park/marine park” – encompassing protected marine areas, AONBs, SSSIs, nature reserves, ancient woodlands etc. – would be focused almost exclusively on conservation and wildlife and can be much smaller in scope, with much tighter planning regulations. National parks could be administered directly by the Welsh Government; nature parks by a statutory board.
Should national parks be nationalised? – As mentioned, England, Scotland and Wales are seemingly unique in that “national” parks are largely in private ownership. In most countries, national parks are in state ownership. This might not be practical as people live and own property in the park areas when most national parks in other countries are not permanently populated.

