Foxley Wood

Yesterday we headed to Foxley Wood, which is about 30 minutes NW of Norwich, on an Ecology field trip. The purpose of our visit was to learn about coppicing as a management strategy, ancient woodland indicator species and to have a go at some plant identification. Unfortunately, we didn't do much of the latter due to the terrible weather.

Foxley Wood is Norfolk's largest remaining ancient woodland and over 350 flowering plants have been recorded on the site. This includes one of the UK's least known native trees: the Wild Service Tree Sorbus torminalis, which is rather inconspicuous for most of the year, until it becomes covered with white blossom in late spring and its leaves turn a coppery-red colour in autumn.

Coppicing is an ancient woodland management technique that is used extensively at Foxley Wood in order to maintain a matrix of woodland growth stages to benefit biodiversity. Coppicing involves felling the same stumps near ground level and then allowing shoots to regrow from that stump, whilst also leaving certain large trees (standards), typically mature oaks. Where coppicing occurs, the woodland is often divided into blocks and coppiced on a rotational cycle of about 15 years in order to maintain a variety of woodland ages. Historically, coppicing was used to produce numerous straight stems from each coppiced stump, which would then be used for posts, fencing and firewood.

Coppiced Hazel tree showing the numerous new stems
growing from the coppiced base.

During our wander around Foxley Wood, it was really interesting to see the different ages of coppice blocks and to be able to compare and contrast it with the ancient woodland and grazed areas. This allowed us to see first hand the effects of the different management practices and I found it particularly interesting to see the stark differences in the under storey between the coppiced areas and the ancient woodland, and also how the plant assemblages changed too.

Coppiced woodland with standards (left) compared to Ancient woodland (right)
Very different under storeys in the two areas with it being much denser in
coppiced areas and much thinner in the ancient woodland.

One of the main aims of our trip was to learn about ancient woodland indicator species (AWIs), and despite the weather, we managed to locate quite a few of the early flowering AWIs that are found at Foxley Wood. The term ancient woodland refers to land that has had continuous woodland cover since at least 1600AD, and AWIs are a group of species, typically vascular plants (but also some invertebrates and lichens), that are more common in ancient woodland than in recent sites and display a number of characteristics:

  1. Rarely occur outside of woodland, and if they do, then they indicate a long temporal continuity of woodland cover.
  2. Capable of growing in shade, though don't necessarily grow exclusively in shade.
  3. Reliable indicators, in at least part of the region being surveyed.
  4. Slow colonisers - normally have a small seed shadow, meaning that seeds don't disperse very far each year, so colonisation of new areas is slow.

There are approximately 100 plant species that are thought to be good indicators of a woodland's age, and when a woodland shows more than about 10 of these indicator species, it is likely that the wood has existed for a long time. AWIs vary between the different regions of the UK and finding one AWI species alone is not enough to determine a woodland's age, but finding combinations of AWIs suggests different things about the woodland's age.

A carpet of Honeysuckle (Lonicera periclymenum) - one of the 12 ancient
woodland indicator species that we were looking for.

While at Foxley Wood, we were on the lookout for 12 AWI plant species, and despite the dreary weather we managed to find 7 of them. One of the AWI species that we managed to find was Wood-sorrel Oxalis acetosella (also known as Common Oxalis). The Oxalis part of the binomial is due to the presence of oxalic acid within members of the genus, while acetosella is in reference to its sour taste. Wood-sorrel is a small plant that flowers between April and May. It has white flowers which droop down until the dappled sunlight reaches them, upon which the flowers tilt upwards. Each flower has 5 petals and tiny, purple veins. The leaves of Wood-sorrel are trefoil and fold down into a tent during the night, but flatten out again during the day.

Wood-sorrel leaves (left) - © Phil Dowling & Wood-sorrel in flower (right) - ©

Apparently, all parts of Wood-sorrel plants are edible, and the leaves (fresh or dried) are often used in alternative medicines. The leaves are said to have diuretic, antiscorbutic and refrigerant actions, and a decotion (an extract made by mashing, then boiling the plant) made from the pleasantly acidic leaves is used for high fevers, both to quench thirst and allay the fever itself. Although it may be consumed freely, excess consumption should be avoided as the oxalic salts are not suitable for all constitutions and may have unwanted effects.

Further reading:

1 comment:

  1. If you get a chance, the books about woodlands by George Peterken and Oliver Rackham on woodlands are great reads. Both were recommended to me a while ago - so they may have been superseded! The leaves of wood sorrel taste like apple peel to me! Cheers - SM