Juniper regeneration

At Bedfordshire's Kensworth Quarry work is ongoing to preserve and boost the county's last remaining juniper trees.

Many counties in southern England have lost more than 60% of their juniper population - in Bedfordshire the last remaining population is found at Cemex’s Kensworth Quarry, which is a working quarry and a Site of Special Scientific Interest (SSSI). Juniper is an evergreen shrub or small tree in the cypress family. They are slow-growing, typically they grow about 3-5cm per year and live on average for about 100-120 years, however they can live for longer, for example, the oldest recorded juniper in the UK was aged at 255 years.

This species is dioecious, which means individual plants are either male or female, unlike most tree species, where both male and female flowers occur on the same tree. Male flowers appear as yellow blossoms near the ends of the twigs in spring and release pollen, which is wind-dispersed. Female flowers are in the form of very small clusters of scales, and after pollination by the wind, these grow on to become berry-like cones. Berries are green at first, but ripen after 18 months to a dark, blue-purple colour. Due to the long ripening period, berries occur on juniper throughout the year - it's often possible to see them at different stages of development on the same plant (as above).

Juniper trees growing in Bedfordshire

There is a long association of juniper with people and it is best known for its culinary, medicinal and ritual properties. The most famous use of the juniper berries is in the flavouring of gin as well as flavouring many foods and liqueurs; juniper berries may also have been added to food for their medicinal properties, said to aid digestion and to be a cure for various stomach ailments. The earliest recorded medicinal use of juniper berries occurs in an Egyptian papyrus dating back to 1500 BC, in a recipe to cure tapeworm infestations.

The junipers at Kensworth Quarry are found just south of the quarry dispersed along two rows of chalk cliffs in a roughly 1 hectare area. All of the mature shrubs were being engulfed by invading scrub which was limiting their access to light, water and nutrients and making it hard to count how many there were.

To preserve the last remaining Bedfordshire population we needed to be proactive and on 5 December 2016, the Wildlife Trust BCN, with the help of Cemex, spent a day clearing hawthorn and blackthorn scrub from around the junipers to give more space and allow them to grow unimpeded. This management opened up the ground layer, improving conditions for seedling establishment. Clearance work also allowed us to count them and overall we found 17 junipers, a mix of male and females, of which 11 were mature and six were seedlings growing underneath or near the mature shrubs.

We also removed some ripe berries and took cuttings from the mature shrubs to grow on: in the future they'll be planted in suitable areas to expand the population. Six 1m tall junipers grown from cuttings taken here several years ago in a tree nursery are now ready for planting into the publically accessible nature reserve at Kensworth quarry.