Lowland heathland, upland heathland and mountain heaths are among the priority habitats of the UK Biodiversity Action Plan. Afforested former heathlands have the potential to be restored and this is already being attempted. Obviously this involves clearing trees but the more detailed methodology needed to do the work cost-effectively is not yet clear.
The Penlan heathland restoration experiment is a partnership project between Forest Research and the Pembrokeshire Coast National Park Authority.
Penlan, in the Preseli Mountains of north Pembrokeshire, was a Sitka spruce forest planted in 1971 on former heath land. The National Park Authority is restoring the site to heath, scrub and native woodland.
The experiment compares different ways of dealing with the brash and the thick layer of dead spruce needles. It also tests whether it is beneficial to re-seed the site with appropriate heathland species.
The brash treatments:
- Leave it lying in strips (normal condition after timber harvesting)
- Spread it evenly
- Burn it
- Remove it.
The needle layer treatments:
- Leave it intact
- Break it up
- Mulch it with the upper 7.5 cm of top-soil.
Eight combinations of these treatments are repeated with and without the addition of a seed mix collected from a nearby heathland area.
The treatments are being evaluated by seeing how closely the new vegetation comes to resemble that of intact heathland nearby. Lessons from this experiment should help improve the success rate of future heathland restoration projects.
For further information about this work please contact Russell Anderson.