Blog - deer
Parts of a tree (1): The Bark.
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]
Changing forests and woodlands.
For millions of years, forests and woodlands have been changing - as a result of natural regeneration, storms, fires and climate change. However, with the expansion of human populations, woodlands and forests have been cut down to make way for towns, cities and the infra-structure of ‘modern’ life. Sadly forests, and woodlands such as those in the path of HS2, are still disappearing. ‘Untouched’ rain / tropical forest is being cut down to make way for cash crops; plus vast wooded areas have been destroyed by fire in Australia, Sweden and on the West Coast of the United States in recent years. Clearfell of any forested area for timber or agriculture involves the removal of all trees / vegetation and is sometimes followed by burning of the remaining debris. Clearfell can also have unintended consequences (beyond the loss of entire animal communities. An Australian study has shown that it lowers soil nutrient levels - notably nitrate and phosphate. Furthermore, the use of heavy machinery in clearfelling can compact the soil and its consequent exposure to the elements can lead to erosion (rain runoff). When an area is subject to intense fire, there is a drop in the organic carbon content of the soil and structural damage to the soil; it can take many years for such fire-damaged soil to ‘recover’. Forests and woodlands support the vast majority of land-based species. However, the species that we see today on a woodland walk may be different to those our ancestors might have seen five hundred or a thousand years ago. Certain species only survive in relatively undisturbed (and ancient) forests / woodlands. There are species that can ‘deal’ with disturbance and are adaptable, indeed opportunitistic, such as red deer and fox. The same can be said for certain plants species, which can become invasive. Changes in species make-up and biodiversity do not always immediately follow loss of forest or woodland. Generally speaking, the longer the life span of a species then the longer for the effects of forest loss to become apparent. It may be that the effects ‘span’ generations, raptors / birds of prey may manage to raise their young in the immediate period following loss of forest or woodland. But their offspring may struggle to survive in a depleted environment. It might be that with limited resources an animal might simply not reproduce for years, if ever again. Consequently, the impact of forest destruction / loss that species depletion might not be apparent for many years. The loss of forests and woodlands has lead to many local, national and inter-national initiatives to offset these losses: for example, New Zealand’s ‘One Billion Trees” project and the Nature Conservancy’s “plant a billion trees’ campaign. Broadly speaking, reforestation involves the planting of native trees in an area, whereas planting with new (non-native) species is afforestation. Recent research suggests that whilst non-native plants often grow faster than native species, they also have less dense tissues (think: oak versus larch) and decompose more readily, which can contribute to more rapid cycling of carbon. This will not help to mitigate climate change. It is also important to consider which trees might prosper and offer resilience in the light of climate change. Our climate is changing and will be different in the future, with summer temperatures being higher. We have already seen more extreme weather events (leading to flooding and wild fires). Forestry England has a number of tools to help plan which tree species will be suited to a site, now and in future. There is ESC4 which offers a means to help forest managers and planners select tree species that are ecologically suited to particular sites; and there is also the climate matching tool. As Forestry England says this is “so that we can see which places in the world currently experience the climate we are projected to have in future. We can compare these different places to help us plan which tree species will be suited to a site, now and in future”. One strategy is to create woodlands that are more diverse, as it thought that diversity helps woods more resilient to climate change. This can be through encouraging a range of different, but carefully selected trees to grow, and being aware of the provenance of seeds or saplings.
At last, my own wood.
So! My story begins many, many years ago when I had a dream to own my very own woodland. Of course I didn’t believe it would ever come true, however, a dream’s a dream and one day I decided to go for it. I sold my house and downsized in a big way so that I had funds to realise my dream. Then the search began, three years of searching. Everything I found was too far away, too expensive, too big, too small……!! Then, I fell on one for sale with Woodlands.co.uk, just five minutes from home and 6½ acres – perfect! I will never forget the day of completion. I was soo excited and couldn’t wait to get the key to my gate so I could officially walk through my very own woodland. As I struggled through the bracken and brambles, which in themselves were a delight…. Little birds popping out, discovering little plants, blackberries, raspberries, self-set holly bushes, oak trees… It was just wonderful. The majestic Silver Birch trees towering over me giving sneak previews of the sky above. The smell was just amazing…. Was it my imagination or was the air so pure with subtle scents of the tree and plant species. I was truly in my element. My intention was to spend as much time there as possible so setting up camp was a priority, along with a pathway so as not to disturb any wildlife/budding growths when clambering through the dense overgrowth. I cleared an area for the ‘camp’ which was soon to consist of a fire pit, stumps from the larger fallen trees for seats, a frame from cut off trees to throw a sheet of tarpaulin over - should the rain come. This little secret area became a huge part of the early days at the woodland. There’s nothing quite like boiling a kettle on an open fire, cooking lunch using the branches collected. The smell, the warmth not to mention the smoke to keep the unwelcome little bug visitors away!!! Imagine my excitement when 7 deer came strolling past for the first time which gave me the idea to have an area to encourage them to visit so that we could hopefully see them regularly. Over the next few months, pathways were developed so that all areas of the woodland could be accessed with various areas of interest including a sensory garden, allotment, orchard, natural pond, various picnic areas, deer watch area, an ‘observatory’ to shelter us in the evening / night where we hide out and watched the night wildlife (deer, rabbits, owls), and our very own 'Hartley Hare' !!!). On clear nights, watching the stars through the telescope is just amazing… there’s no light pollution so the sights are just amazing. Then there’s the memorial garden, inspired by my sister who I lost to Covid in March 2020. And, who could have a woodland without a bit of Winnie the Pooh – a tribute to Hundred Acre Wood!!! I have put bird boxes up to encourage varieties including Tree Creeper, Blue tits, Great Tits, Sparrows,, Nuthatches, Owls and baskets for Sparrow hawks, Hobbits and Buzzards. The original disappointment as squirrels moved into the Barn Owl box and Pigeons into the Tawny Owl box soon became delight as the babies arrived. It was so lovely watching the busy parents rearing their young. Then, the following season, guess what….. yes!!…. A Barn owl nested!! Friends and family just love to visit the woodland to enjoy the magical relaxing atmosphere; to explore the pathways leading to the various little nooks and crannies to search for plants, insects and just to sit quietly, listening to the birds and the rustle of the leaves. To anyone who has never thought of owning a woodland before, just imaging the freedom, the space, the never ending discoveries of plant life, tree life, wildlife and with imagination, you can make more than one dream come true. To anyone who is thinking of owning a woodland…. Do it! You will have nothing but pleasure and peace, and experience an immediate shift in your mental wellbeing and, if like me you have physical disabilities, the change of pace, the air, the green will have a positive impact on your aches and pains!!! Thanks to Lesley for the above enthusiastic account of her woodland adventure.
Deer, damage and the pandemic.
Across the UK, there are several types of deer to be found in woodlands and rural areas namely : Red deer Sika Deer Roe Deer Reeves Muntjac Deer Fallow Deer Chinese Water Deer In recent times, the number of deer has increased and it is thought that there might be as many as two million wild deer in the UK - the highest number for many hundreds of years. Unfortunately, deer can cause substantial damage to trees and woodlands. Their feeding can cause a range of problems, which can include [caption id="attachment_34910" align="aligncenter" width="650"] Deer damage - bark removal[/caption] Stripping shoots, flower buds and foliage from plants Damage to woody stems, where a deer has bitten part way through the stem and then the shoot is tugged off - leaving a ragged end Eating the bark from younger trees. This mainly happens in winter when other food sources are scarce In addition to the damage associated with their browsing / eating activities, there is also the damage done by male deer who rub their heads / antlers against the trunks of younger trees. This rubbing may be for scent marking or to remove the outer skin (velvet) present on a new set of antlers. The antler rubbing results in cuts in the bark. [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 and tree guards in place[/caption] Deer numbers are reduced by culling in order to supply restaurants, farm shops, and the hospitality sector with venison. However, with the onset of the pandemic and subsequent lockdowns / restrictions the demand for venison dropped significantly (as has price) so very few deer were culled. Consequently, the number of deer is increasing. Deer have probably gone through one or two breeding cycles since the first national lockdown, and numbers are set to increase. The increase in deer numbers not only affects the trees in a woodland but also plants of the herb and scrub layer. The loss of plant species and aspects of the structure of the woodland means that particular microhabitats are lost so that species such as nightingales and warblers are at risk. Without careful management of deer numbers, woodlands could become much more ‘uniform’ as deer have no natural predators (in the UK). It is important that deer numbers are monitored as they will do significant (most) damage to woodland in Spring as there’s not much food elsewhere for them. Young trees are particularly at risk, unless they are protected.
Rewilding Britain’s report : connectivity and biological corridors.
Sadly, the number and range of various species in the U.K. is decreasing, biodiversity is falling. Our wildlife-rich areas are actually separated and fragmented, by tracts of intensively-farmed land, by motorways and roads, and the ever increasing spread of urban areas. The dispersion and isolation of wildlife areas makes it difficult for both plant and animal species to move. The ability to move around is ever more important as a result of climate change. Rainfall patterns and average temperatures in different regions are changing, extreme weather events are more common. For a species to stay in its ‘comfort zone’, it may need to move ‘northwards’ as climate change continues. According to a report released by Rewilding Britain, the speed at which species need to migrate in order to stay in their ‘comfort zone’ is approximately some 5km / year Read more...
Bark : damage
Wind, fire and frost can seriously damage or kill trees. Animals also wound them when they feed on bark tissues, and when they rub their bodies or antlers against tree trunks. Insects, like bark beetles can cause significant damage damage to woodlands and forests. The extent of damage to trunks and the bark of trees varies considerably in relation to the nature of the ‘attack’. If the damage to the bark is severe and the vascular cambium is exposed then neither new water nor sugar conducting tissue can be formed. Damage to the (outer) cork cambium (phellogen) will limit the trees ability to form the outer tissues of the bark - which protect the tree. If the damage is restricted to the outermost bark layer then this will render the tree more susceptible to further damage (be it from herbivores or temperature extremes). Read more...
Tree planting again …..
The woodland’s blog has reported on various tree planting initiatives, particularly that presented by the CCC (Committee on Climate change). This Committee has called for some 1.5 billion new trees to be planted by 2050. This would require approximately 30,000 hectares of land to be planted each year. If this were to happen, it would increase Britain’s forest / woodland cover from 13% to 19%; probably the highest level since Roman times. Sir Harry Studholme, the outgoing chairman of the Forestry Commission has said that such a target is achievable but has urged caution so that mistakes of the past are not repeated. Read more...
Disease in American deer – chronic wasting disease (zombie deer disease).
Chronic wasting disease (CWD) affects deer, sika deer, reindeer, elk and moose. It was recorded in the wild in the United States some forty years ago, but had been seen in captive deer back in the 1960’s. Now the number of reported / observed cases is increasing; it is spreading in the United States and Canada. Some 24 states in the U.S and two Canadian provinces have recorded cases. Chronic wasting disease also known as ‘Zombie Deer Disease’ affects the central nervous system of the animal. The deer experience loss of co-ordination, weight loss, bouts of extreme aggression. And eventual death. It is a neuro-degenerative disease. The affected animals have a ‘wasted appearance’ and a ‘vacant stare’. Read more...