In search of Juniper: part 1

Alasdair Fagan – Conservation Graduate Trainee

The intrinsic value of Common Juniper (Juniperus communis subsp. Communis) is significant in both cultural heritage and the natural environment.

Many people may have heard of Juniper due to its use as flavouring for gin (the word “gin” derives from an Old French word meaning “juniper”). In fact juniper has historically had a range of practical uses which includes use of its wood in crafts in mainland Europe, and as a key ingredient in a number of historical traditional herbal medicines. Juniper charcoal was also highly desirable as it provided a fast explosion quality to  resulting gunpowder, for instance at the ‘Low Wood Gunpowder Works’ (1798-1935) in the Leven Valley in Cumbria.

Common Juniper has the most extensive natural global distribution of any woody plant. Its range extends across the Northern Hemisphere and includes North America, Europe, Asia, and consequently is of little conservation concern at a global scale. However, in the United Kingdom juniper numbers have fallen drastically. There is a recognised lack of natural regeneration, which has raised concerns for the future sustainability of Juniper populations throughout England in particular.

Common Juniper  is therefore a priority species for conservation. It is listed as a species “of principal importance for the purpose of conserving biodiversity” in the Natural Environment and Rural Communities Act (2006) under Section 41 (England).

It is a coniferous shrub or tree which is both evergreen and perennial. It often lives to ages over and above 100 years during which time it often grows up to and including 4 metres in height but has been recorded at heights up to 10 metres. It can grow in a diversity of forms including a variety of upright bush profiles, low-growing mats and towering spires.

Characteristic of upland ecosystems (but can be found down to sea level), Juniper is typically found in moorland, heath and woodland (Pine and Birch) systems and can tolerate a variety of habitats including both acidic and alkaline soils. As one of only three conifers native to Britain (together with Yew and Scot’s Pine) you would be forgiven for expecting it to be widespread and ‘common’ as its name would suggest. Unfortunately Juniper has now become a relatively rare sight in the United Kingdom, and in particular in the North York Moors.

As a ‘dioecious’ plant (plants are either male or female, and not both as with many other plant species) both genders must be close enough to one another such that the wind-borne pollen of male plants may reach and pollinate a receptive female. If this is not the case for a population it has no chance of successfully reproducing and will eventually die out.

Ecology

Juniper may not necessarily appear to be visually engaging to the viewer but it holds a considerable significant biological importance.

A characteristic native invertebrate fauna comprising 35 insects and 3 mites are supported by the plant, some of which have specialised habitat requirements and restricted distributions. These include both the Juniper Pug Moth and the Juniper Carpet Moth.

Juniper shoots and ‘berries’ (or modified cones) provide an important source of food for wild birds (such as thrushes, waxwing and fieldfares) and mammals (like voles). In addition, over 40 species of fungi, plus a range of epiphytic lichens and bryophytes, are known to be associated with the plant.

During my time here at the North York Moors National Park Authority I have been tasked with the surveying and monitoring the health and progress of existing and planted Juniper throughout the National Park, a priority species in our Local Biodiversity Action Plan. In my next post I’ll be letting you know how that’s going.

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