The lowland heath reserves of Burlish Top and Rifle Range in Kidderminster have for many years been managed to promote this nationally scarce and threatened habitat.

Initially, this work revolved around the removal of trees and tall scrub. Now the much more open landscapes need to be maintained and annually cut to remove the competition of more aggressive plant species from the traditional heathland plants. Wherever possible, grazing is also used. Some scrub needs the attentions of two-legged volunteers.

For many years now, this has been carried out by the pupils of Bewdley High School and the young people of Stourport Pupil Referral Unit. Rangers also get heavily involved.

The task itself is a bit like gardening, but on a huge scale, and you really start to get a connection with the land. Even in winter, there is still much invertebrate life to be seen foraging among the stands of heather and yet after 10 years of doing this, it is possible to make new discoveries.

The most recent of these came when I was uprooting a young oak sapling from among the heather stands. At the base of the stem just at the point where it enters the soil I noticed a collection of strange structures.

They looked just like the barnacles you would see clinging to rocks at the seaside. The "barnacles" seemed to be embedded into the fabric of the tree, some were open while others were closed.

From the embedded nature of the "barnacles" I felt the most likely occupants were gall wasps. These are a species similar to the wasps that are responsible for oak apples and marble galls we more frequently see higher up on more mature oaks. This suspicion was confirmed through later research as this species had been named the Barnacle gall.

The adult is small and unobtrusive, emerging from the protection of the gall where it spends most of its life at a specific time of year. It then searches out a suitable oak or even acorn on which it lays its eggs. I'm not even sure if this species even needs to find a mate, as there are several species of gall wasps. However, despite many detailed scientific attempts, males have never been found.

The egg then interacts with the genetic make up of the oak trees cells and causes the young tree to produce the structures that I found and provides both shelter and nourishment to the wasp's larva.