There are now more deer in the UK than there have been for 1,000 years.  Probably between 650,000 and 2,000,000, of which about half live in Scotland. Dormice like sleeping and can sleep for up to 7 months a year. UK woodlands are home to half the world’s flowering bluebells. There are 15,000 species of fungi, on land, in water and even on plants and animals. Swallows migrate annually to Southern Africa travelling 6,000 miles twice a year. Grey squirrels have become a problem because they were released deliberately, in 1876. Half the deer species in the UK were escapees - three of our six deer species, being Muntjac, Sika, Chinese Water Deer. Conifers have been around so long that they were dinosaur food - about 300 million years. The oldest British trees predate Christianity, Islam and Buddhism. One of the oldest is the Fortingall Yew in Scotland, estimated to be as much as 3,000 years old. Not all conifers have cones - the Juniper, for example, has fruits that are tiny, round, fleshy and berry-like.  

Bark exists to protect a tree from ‘attack’ by the elements, pests, ‘predators’ (animals who would eat it) and disease causing organisms.  There is no easy definition of what constitutes bark,   a slightly technical definition might be ‘the tissues that lie outside the vascular cambium'.  The vascular cambium is a layer of dividing cells that gives rise to xylem tissue and phloem tissue.  The cells nearer the centre form the xylem, those towards the outside form the phloem.    The inner part of the bark contains various types of living cells, for example, glands that produce latex (as in natural rubber), oils and resins.  Moving outwards, there lies the rhytidome or outer bark, an amalgam of living and dead material - notably cork cells.  The cork cells fill with a waxy material - Suberin. Eventually, these cells die and form much of the bulk of the bark.  The nature of bark is immensely variable. Wind, fire and frost can seriously damage or kill trees but bark helps  to protect them.   Trees are eminently combustible as is evidenced by the recent forest fires in Australia and California. However, some trees have a very thick bark that can protect them against fire.  The cork oak has a bark that can be up to 30 cm thick, it is so thick that it can be harvested periodically without killing the trees.  Cork oak is grown extensively in the mediterranean region. Giant Redwoods too are noted for having an extremely thick bark. Their bark is very fibrous and can be up to three feet thick, it offers protection against fire (and rock fall which is also a hazard in their home habitat). In contrast to cork oak and redwoods, some trees like the eucalypts have a bark that is rich in oils and very flammable.  The bark also ‘peels’, strips are shed onto the forest floor. There are many species of Eucalyptus and several different types of bark are recognised.  [caption id="attachment_35352" align="alignleft" width="300"] Woodland recovering from a fire[/caption] If and when this oil rich bark builds up on the forest floor, it will contribute significantly to the intensity and ferocity of any fire. Indeed, it has been likened to adding petrol to a fire ’3 centimetres of leaf litter can cause a conflagration equivalent to one fuelled by a centimetre of refined gasoline’.  The leaves are also rich in oil so the crowns of the trees can also contribute to / exacerbate any fire.  The peeling or exfoliation of bark is not restricted to Eucalypts, it can be seen in trees much closer to home - such as the birch.  Its bark can be removed in long strips and has been used in covering a canoe or roofing material. Whilst bark can protect against fire, it can also deter animals - large or small from inflicting damage.  For example, there is an African species of Acacia known as knobthorn that has a bark covered with thorn-like structures.  These 'thorns' deter elephants from eating the bark.  Elephants can consume a lot of vegetation in a day and tree bark is much favoured.  A variety of animals may feed on bark material, for example deer, squirrels, and beavers, but the list could also include orang-utans, rhinos, bush babies and porcupines. North American porcupines use their large front teeth to eat bark and stems. Bushbabies generally feed on insects during the wet seasons, but during drought / dry periods - they feed on the resins / gum that flows from the trees in their woodlands. In the UK, a lot of bark damage is done by deer, especially during the winter months when other food sources are limited.  In the summer months, male deer rub their heads / antlers against the trunks of trees - inflicting damage.  Such activity can prevent regeneration in natural woodlands.  Tree guards may be needed to allow young trees to establish themselves (or fencing to create a ‘deer free’ zone).  Guards also protect against rabbit damage.  Grey squirrels can also cause damage to trees as they gnaw stems to reach the ‘sweet’, sap-filled tissues just below the bark, this activity is usually seen in late Spring and early Summer. [caption id="attachment_5312" align="alignleft" width="300"] xylem vessels[/caption] Whilst bark is broadly protective, it can also offer a home to certain pests.  Bark beetles lay their eggs below the bark so that when the larvae hatch, they can feed on the nutrient rich tissue of the cambium and phloem.  Bark beetles have been responsible for the loss of millions of trees in the United States and Canada.  The scale of the loss is much greater than in the past, when cycles of beetle infestation and fire created a mosaic across the countryside of young and old trees.  Ageing stands of trees coupled with warmer winters (which have helped the overwintering stage of the insect)  have contributed to the spread of bark beetles.  The beetles breed and feed beneath the bark, damaging the phloem and cambium tissue.  Consequently, the tree's transport systems begin to fail and the beetles may also introduce disease-causing fungi and bacteria. To a certain extent, trees are able to repair damage to their bark but the response is varied according to the nature of the damage and the tree involved. Some trees can produce ‘callus tissue’ that heals over the ‘wound’, leaving a scar. Some trees, such as the pines, produce resins and antimicrobial compounds in response to injury.  This sticky resin may trap insect invaders as is witnessed by those trapped in time capsules of amber.   Apart from bark beetles, other animals and plants live in or on bark in a variety of associations, some parasitic as is the case with fungi (like the polypores), whilst lichens and mosses are epiphytes.  They use the bark as a substrate on which to live, grabbing nutrients and water from rainwater as it trickles down.   The many uses of bark tissue can be left for another woodlands post. [caption id="attachment_39940" align="aligncenter" width="620"] Section through bark[/caption]

Images of deer in a woodland clearing may seem charming, but quite how deer and woodlands interact is not fully understood. It is certainly the case that deer affect tree regeneration;  they browse on saplings and can cause extensive damage to bark (through territorial behaviour / antler rubbing) to larger trees.  The lower levels of the plant communities are also affected by deer.  By changing these, deer also can change the animals to be found in this lower layer of a woodland. Research by Dr. Simon Chollet and colleagues showed that deer interaction can influence soil water availability,  and soil fertility. Their study looked at the role of Sitka black-tailed deer on the plant communities in forests in parts of western Canada. Chollet et al. examined twenty areas where deer were excluded for some two decades. An exclosure is a limited area from which browsing animals, such as deer, are excluded by fencing or other means. Unsurprisingly, they found that deer did have a significant effect on the plant communities. The exclusion of deer resulted in an increase in vascular plant richness and cover, though bryophyte (mosses etc) cover declined. They also found that with the deer gone,  the exclosures started to develop broadly similar plant communities.  There was no increase in beta diversity - that is the development small, localised communities of varying character. It was suggested that the dominance of certain species within the exclosures was linked to historic over-browsing.   Consequently, those plants that are able to withstand the presence of deer over time are best placed to achieve ‘dominance’ once this grazing pressure is removed.  This might explain why the different enclosures developed similar vegetation and plant species.    Biotic homogenisation has been seen in the UK woodlands, as was discussed in a previous blog.  It can be the result of introduced species, pollution (eutrophication - increased nitrate and phosphate levels), which allows botanical thugs (like nettles) to dominate, or poor woodland management.

Today there are more deer in the UK than at any time since the last Ice Age.  They no longer have any natural predators in woodlands or fields. Total deer numbers are conservatively estimated at about 1.5 million and the rapidly expanding deer population threatens woodland biodiversity.  Over-grazing and browsing, particularly in ancient woodland, continues to have two very unfortunate consequences for conservation.  First, it can lead to a decline and loss in plant species in a given area, which often includes oxlip and bluebells.  Deer frequently damage saplings and cause other damage by stripping bark with their antlers. Read more...

Nightingales are migratory birds and fly into the U.K. in the Spring, having spent the winter in Africa. The nightingale is particularly well known for its song; (a wma file of which can be found here).  However, not everybody in the UK is likely to hear them singing.  It is not found in Scotland or Wales, and in other places its numbers have fallen quite dramatically.  It is now mainly found in the South-East, especially Kent, Sussex, Suffolk and Norfolk. A sighting is unlikely; nightingales are shy, drab brown birds who seek the dense vegetation described below. Read more...

Man has created the necessity for deer management by eradicating the natural predators of deer - the wolf, bear and lynx.  Escapees from deer parks introduced several non-indigenous varieties into the wild.  During the two World Wars, when manpower was limited, deer parks were left in disrepair and escapee deer spread.  With the formation of the Forestry Commission, land owners were encouraged to plant trees.  The aim was to create a national reserve of timber against future conflicts, but also created an ideal habitat for deer.  Improvement in farming practices provided more food. Deer Damage Deer are responsible for forestry and crop damage and, as they increase in number and range, more damage is now seen in gardens in urban areas. The damage they do to trees and plants are as follows: Fraying is damage done by territorial behaviour when deer rub and trash antlers on trees and shrubs. Browsing this is caused by the deer’s natural feeding and can kill or inhibit the growth of trees (note in the image below, small trees are the same age as the larger ones).  Has the effect of creating 'bonsai'. Control Measures There are numerous so called effective deterrents i.e. lion dung, sweaty socks, chemical agents and mechanical worriers, these are all short term solutions.  The only effective control is proper deer fencing put in by qualified persons, bearing in mind that roe deer can get under an 8” gap. Proper fencing is expensive and is not cost effective on large woodland areas therefore most areas have deer culling taking place in some form or another. [caption id="attachment_34415" align="aligncenter" width="700"] Remnants of birch woodland near Loch Muick are subject to browsing by red deer (especially in the winter), so temporary fences have been out in place to allow for regeneration.[/caption] [caption id="attachment_40967" align="aligncenter" width="675"] Fencing in place[/caption]   Culling This is done these days more and more by trained personnel who have obtained qualifications like DSC Level 1 and 2 from Deer Management Qualification.  These qualifications mean that all culling should take place in a professional, safe and humane manner enabling  field post-mortem to be carried out to confirm the health of the deer and its fitness for human consumption and carried out under strict hygiene  procedures The gralloch (Scottish word for evisceration i.e. removal of internal organs) must take place within 30 minutes maximum or less in the summer, after being culled the carcass must be bled immediately to stop the carcass becoming unfit for human consumption, by law. This generally has to be done in the field depending on how far one has to travel and disposal of the head, feet and gralloch should be by burial in the field (ensuring it is not near a water course).  Thus, taking other countryside users into consideration. Venison  Venison is one of the best meats to eat (recommended by the heart foundation) it is free-range meat with approximately 60% less cholesterol. The purchasing and eating of venison helps promote good deer management as they are looked at as a natural renewable resource,  instead of a pest. All six species of deer in the uk produce good quality venison,  although there is a slight difference in taste between them depending on what the deer have been eating and this can produce quite a unique taste.  It is recommended that a carcass be hung for at least three days to help venison mature, hanging for longer would produce a stronger taste (this should always be in a fly and vermin proof area and at 7 degrees C). Deer Species in the UK Red Deer                        One of our indigenous / native deer and the largest Sika Deer                        Introduced by the Victorians into deer parks and collections, medium sized. Fallow Deer                   Introduced by the Normans for food and hunting. Roe Deer                        The second indigenous / native deer, nearly wiped out in the Middle Ages  Muntjac Deer                Introduced by the Victorians. Chinese Water Deer  Introduced by the Victorians.   [caption id="attachment_557" align="alignleft" width="202"] Fraying[/caption] [caption id="attachment_563" align="alignleft" width="451"] effects of browsing[/caption]