|Although much of the soil across the reserve is acid as a result of the Rhododendron invasion, a small area of dry woodland has a
decidedly alkaline soil. This is thought to be due to the presence of calcium in the
rock layers beneath.
The ground flora in this area is much different from
that elsewhere on the reserve. No Rhododendron grows
here. Trees such as Ash can be found and Hart's Tongue Fern grows in proliferation
close to the ground. What is surprising is that the boundary between acid and
alkaline soil is very clear. The Hart's Tongue Ferns only occur within a sharply
defined area. They are not present growing in the acid soils which surround this
small "alkaline island".