Tree Care & Management
In this section we detail TREE PLANTING, provide some guidance on the PRUNING of trees and outline some current concerns regarding PESTS AND DISEASES, providing links where further infomation can be found.
A database of 60 tree species grown in Britain:
Tree Planting & Aftercare
There's more than one way to plant a tree!
However, my advice would be to plant small. The young tree on the left will settle in easily and start to grow more or less straight away. The tree on the right will make an immediate impression but, with a root-ball perhaps one tenth the size of what it would have been had it been open-grown, it will spend the first several years trying to establish a root system big enough to support it. In that time it will hardly put on any top-growth so within a few years, the small tree is likely to catch up.
There may be good reason to choose large planting stock, but on the whole, smaller is better!
Right Tree, Right Place
"Right Tree, Right Place" is a principle in urban forestry and landscape design that stresses the importance of selecting and planting trees that are well-suited to their environment. By choosing the right species for a specific location, whether in a private garden, a city park, along a street or in the open countryside you can ensure that trees thrive while minimizing conflicts with infrastructure, utilities, and other vegetation. This approach not only promotes healthier, longer-lived trees but also enhances the overall ecological, aesthetic, and economic benefits of urban green spaces.
In planning your tree planting, here are a few Dos and Don'ts:
DO select a species suitable for the planting site. Information about a wide range of trees suitable for planting with details about the situations they are best suited to can be found in the Woodland Trust guide 'Twigged'.
Look around and see what sorts of trees are growing naturally: they are likely to be the ones that will suit the location.
While non-native and more exotic species may provide welcome interest in gardens, parks and urban planting sites, native trees are generally more appropriate for the countryside.DON'T plant in sites of special ecological value such as old, unimproved grassland, wet meadows, or in open areas rich in flowering plants that would decline if shaded. Avoid planting under or close to the canopies of established trees Bear in mind that woodland glades and open rides are important for wildlife and shouldn't be filled in by new planting.
DO consider the ultimate height and spread of the tree; make sure there is enough room around it to accommodate its full mature size; ensure that it won't grow to obscure an important view or cause excessive shading.
DON'T plant under overhead cables (and be aware of the possible presence of underground services)
Tree Selection Guides
Guides to the habits and requirements of trees suitable for planting can be downloaded by clicking on the icons below :
The Trees and Design Action Group (TDAG) gives detailed information on over 100 trees in their 'Tree Species Selection: a Guide for Specifiers'.
The Woodland Trust provides a useful guide to British trees with details on their charactristics and requirements:
Tree Stock - Selecting and Planting
Guides are provided below on how tree sizes are defined in the nursery, the forms in which they are supplied along with a planting guide provided by the Tree Council. Further advice is given by following the links below:
Click above for a useful Tree Planting Guide produced by the Tree Council
Trees can be supplied as anything from year-old seedlings up to large, semi-mature trees To find out how suppliers describe their sizes click above
The Pros & Cons of trees supplied in bare-rooted or containerised forms - Click above
Trees supplied in small sizes (whips and transplants) will generally have root systems in proportion to the overall size of the plants; however for nurseries to create plants that are capable of being easily transported and planted, larger tree stock and those supplied containerised will generally have root systems that are much smaller than would have been the case had they been grown undisturbed in the open ground.
In the nursery they will have been carefully fed and watered to ensure they develop well and remain healthy; they will also usually have been given support and generally protected from the elements. However, when planted out into the harsher conditions of the outside world, their small root sytem will struggle to support the tree until they manage to grow out into the surrounding soil suffiently to allow the plant to become self-sufficient and self-supporting. It is for these reasons that it is important that the newly-planted tree is watered regularly until it is established, ensuring that the soil around it does not dry out. It is also important that fragile new roots are not disturbed and broken as a result of movement of the tree, for which reason staking is likely to be required for all but the smallest of newly-planted trees.
Planting
- Trees are generally best planted in their dormant season between November and March. The best results are often being obtained by planting in early winter, while the soil retains some warmth. However, container grown trees can be planted at anytime, although when planted in the summer months they are likely to require regular watering .
- A broad, relatively shallow planting pit is preferable to a deep, steep-side one: it should be between two and three times the diameter of the container or root ball and make it slightly deeper by lightly forking over soil in the bottom of the planting pit.
- In most Herefordshire soils a circular hole will be satisfactory but if planting in heavy soils a square hole is to be preferred as this tends to encourage roots to break out into the surrounding soil rather than growing round and round within a circular hole. It is not generally necessary to add compost or other fertilizing material to the hole as this may simply encourage the roots to remain within the confines of he planting pit.
- If the root ball shows any sign of having become 'root-bound' within a container it is helpful to tease out some of the tree's fibrous roots.
- Offer up the tree into the hole and check the level by placing a garden cane or stake across the hole - add or remove soil as necessary to ensure that the final soil level is be the same as when the young tree was growing in the nursery: Add more soil if it is too low and dig down if too high. It is important that the tree is neither buried nor that it is too shallow .
- Ensuring that the tree is upright, fill the hole with the excavated soil and firm it down with your heel when you reach the top.
- A mulch of well-rotted compost or wood-chip may be applied to aid establishment and to suppress weed growth. It should be applied to the surface of the planting pit to a diameter of at least 1m in diameter and to a depth of 75mm. Do not pile mulch up against the tree stem as this can result in damage to the bark.
- Trees must be adequately watered during the summer months for at least the first two years after planting as the tree will have had only a limited chance to put down new roots into the surrounding area from which to absorb water. Creating a ‘dish’ of soil around the base of the tree will help prevent water from running off away from the tree.
- It may be helpful for tree establishment to use one of the mychorrhizal formulations (so-called 'friendly fungi) when planting. For bare-rooted trees this can be applied by dipping the roots in a liquid or gel formulation containing the mychorrizal material; for containerised and pot-grown trees, tablets or powdered formulations can be mixed into the growing medium.
Staking and Newly Planted Trees
A small, well-proportioned young sapling (e.g. whips and feathered trees - see article on Sizes of Trees ) should have well-developed rootball and a relatively small crown and will not usually require staking at all.
On the other hand, newly planted trees of larger sizes usually do require some form of staking. This is not primarily to support the trunk - it is actually beneficial to allow the tree to flex to some extent as this helps it to become more sturdy. However, it is important that the tree doesn't suffer 'wind-rock' as movement at ground level of a newly planted tree is likely to disturbance that will break the delicate fine roots, preventing them from developing and growing out and establishing themselves firmly in the surrounding soil. This is best achieved by providing a stake to support the trunk at no more than about one-third of the height of the young tree.
Click on the image above for details of the design and fitting of tree support system (stakes, ties etc.)
Protecting young Trees
PROTECTION FROM RABBITS AND SMALL BEASTS:
In most situations some form of protection against rabbits and voles will be necessary. Plastic spiral guards are inexpensive and easily available but they can result in a litter problem, especially as they are are often left on too long when they can become brittle and begin to break up. Guards that are claimed to be biodegradable are available, although some take a while to degrade and still create litter in the meantime. In practice it is best that the guards be removed and properly disposed of as soon as the young trees are sufficiently established.
Rabbit guards can also suppress or distort growth low down on the stem of young plants, which can be a particular problem when trying to establish a new hedge as you tend to end up with the bushy growth at the top and little cover below, essentially a sort of a 'hedge on stilts'. Although likely to be more costly, where it is feasible to do so it may be better to use wire fencing mesh (chicken wire), either to provide protection for individual trees or to fence off the planting area.
PROTECTION FROM LARGER CREATURES:
Protecting trees from larger animals tends to be costly, with suitable guards or enclosures often costing more than the trees. Weldmesh tree guards can be effective to protect trees from human predators, but they have to be very well secured and high enough to prevent the tops of trees being snapped off. These may also be suitable to protect from sheep, deer and perhaps from ponies (if tall enough). However, they would tend to be pushed over by larger beasts such as cattle, rubbing against them. For cattle and for horses, substantial enclosures comprising three or four posts with a rail and fencing wire is likely to be necessary, although a system marketed as 'Cactus Tree Guards' are said to be effective. These consist of galvanised steel mesh with outward-pointing spikes that discourage livestock from rubbing against them.
MOWER DAMAGE:
Perhaps the commonest cause of damage to young trees is the careless use of mowing equipment, which can cause wounds that can severely damage or even kill a young tree. Impact by self-propelled lawn-mowers can cause significant damage that can lead to infection and decay, but hand-held strimmers all too frequently result in such damage being capable of stripping the bark off a young tree in an instant. Proprietary strimmer guards can prevent such damage, but an alternative is to lay down and maintain a weed-suppressant mulch, such as composted wood chip. If laid to a sufficient depth (75-100mm) and spread to at least 0.5m around the tree it should not only tend to suppress weeds and thus obviate the need for strimming close to the tree but will also improve soil condition and aid tree establishment.
Pruning
The pruning of trees, cutting branches or shoots from a tree, is perhaps the commonest form of tree maintenance. However it’s worth bearing in mind that all pruning involves wounding the tree to a greater or lesser extent; indeed, poorly executed or unnecessary pruning is perhaps the most frequent way in which trees under human management are harmed.
It’s also worth remembering that no tree ever ‘needs’ pruning; it’s only people that need trees to be pruned! Trees have evolved over millions of years, over the vastly greater part of which they’ve managed to muddle along quite well, entirely without the attention of pruning knife, saw or loppers.
Which is not to say that pruning is necessarily a bad thing; well executed pruning may be helpful in adapting the form of a tree to better suit its surroundings, to lessen the likelihood of potentially damaging breakages and, of course, to increase fruit and flower production; in some circumstances it may even prolong the useful life of a tree. But all pruning operations should be carefully considered, balancing the benefits against the potential for harm.
Advice on HOW TO PRUNE and WHEN TO PRUNE trees is provided on the left-hand link below. The right-hand button provides information on HOW DIFFERENT SPECIES RESPOND TO PRUNING
Tree Pests & Diseases
A list of all of the pests & diseases that can affect trees in the UK is long and potentially alarming; fortunately, most of us not directly involved in tree and woodland care will generally come across only a few. Some, however, can prove to be devastating: Dutch Elm Disease killed tens of millions of mature trees in the 1970s, almost wiping out what was one of the dominant species across much of Britain and thereby transforming the landscape. Chalara Ash Dieback (illustrated on the left) is currently sweeping through the country and has a similar capacity to alter our landscapes. However, unlike English elms, which largely reproduced by suckers and so had very little genetic vaiability , Ash trees reproduce sexually. As a result, individual individuals ash trees are much more variable and there will be a proportion of trees that show a degree of resistance to the disease. It is certain that many thousands of ash trees will die, but it is to be hoped that a residual population of resistant trees will survive to eventually repopulate the countryside.
Below is a link to a list of tree pests & diseases and another showing which diseases tree species are most likey to suffer from. More detailed information on some of the more prevalent ailments follow on further down this page.
FInd out about WOOD DECAY FUNGI by clicking the button on the right.
Acute Oak Decline (AOD)
In the UK, thousands of oak trees are “bleeding,” oozing dark liquid from cracks on their bark. What lies underneath are fluid-filled necrotic cavities that disrupts their life force by impeding the normal flow of nutrients and water. Taking advantage of the weakened state of the trees, are bark-boring beetles, which lay their eggs in the cracks of the bark. These are the characteristic signs of Acute Oak Decline, a disease that can kill a tree within four or five years of symptom onset.
The disease is found mostly on mature oak trees, but younger trees can also be affected. It is a complex infection and seems to be caused by the combined effects of at least two species of bacteria. For infection to occur, it is likely the trees need to be weakened (predisposed) by certain factors, especially environmental factors.
Symptoms include the dark staining of the bark of infected trees and frequently, the presence of the D-shaped exit holes made by the emerging beetles. The tree canopy is likely to thin as the tree nears death, which can take some time although symptoms can develop rapidly over 18 months. Suspectes sightings can be reported to Tree Alert.
Ash Dieback (Hymenoscyphus fraxineus)
Chalara ash dieback is caused by the fungus Hymenoscyphus fraxineus and is a serious fungal disease affecting ash trees. It was officially detected in the UK in 2012 and is now widespread. The fungus causes gradual crown dieback and can also attack the root collar of susceptible trees.Depending on site conditions and the genetic make-up of the tree, a susceptible mature ash may take several years to decline and die; on the other hand small saplings may die within a single season.
Ash trees are an important and significant tree in the landscape, both rural and urban. They provide valuable habitat for a range of wildlife both within woodlands and along corridors such as hedgerows and roadsides. Healthy trees are important to farm businesses and nature, providing shelterbelts, reducing run-off and soil erosion. To give the species the best chance of surviving and re-populating the country side, it is vital that healthy trees are retained: pre-emptive felling of non-symptomatic trees should be avoided. However, infected trees may pose a safety risk to person and property, particualry where they are close to busy roads, public areas or other high-use areas and in such cases safety must be a primary concern. Click links below for further details on management and recognition of the disease.
Chestnut Blight (Cryphonectria parasitica)
Sweet chestnut blight is a destructive disease of sweet chestnut trees (trees in the Castanea genus) caused by the ascomycete fungus Cryphonectria parasitica. It was formerly known as Endothia parasitica. It can also affect a few other plant species.
Dutch Elm Disease (Ophiostoma novo-ulmi)
Dutch elm disease* is fungal infection spread by a bark beetle, Scolytus scolytus (or S. multistriatus). A particularly virulent strain of the fungus was carried by beetles brought into the UK in timber brought from Canada in the 1960s. It quickly spread resulting in the death of millions of trees, including virtually all the mature English Elms in Herefordshire. The reason that the disease was so devastating was the fact that the English elm rarely, if ever, sets viable seed in Britain and reproduces by means of coppice shoots
and root suckers. As a result, all the trees were effectively clones, with identical genetic makeup and all highly susceptible to the disease.
For more information about the disease follow the links below
*Note: It became known as Dutch elm disease only because the fungus was first identified in Holland.]
Elm persistence & resistance:
Trees apparently killed by DED often retain viable roots and these frequently re-shoot. This new growth is also susceptible to the disease but is not reinfected until it has developed to a stage when its bark has become thick enough for the beetle to lay its eggs and the larvae to feed they tend to be reinfected, which may take 10-20 years. As a result, English elm is still widespread in hedgerows, but only as small trees or as part of a trimmed hedgerow. However, the enormous English elms are probably a thing of the past, at least until a resistant variety arises that can replace them. Several such cultivars are being developed and some are available for planting.
Because elm is an important food source for butterflies, disease resistant elms have been promoted by the conservation charity Butterfly Conservation, which has a list of the main resistant cultivars currently available: see Disease Resistant Elms.
Honey Fungus (Armillaria sp.)
When a tree or shrubs dies quite suddenly for no apparent reason, one of the first possible causes to look for is Honey Fungus. This may not be straightforward however; the fungus is quite variable in appearance and the toadstools (equivalent to the flowers of a plant) are not present for much of the year while the fungus continues to act under ground or within the tree. For more detailed information, see below:
Horse Chestnut Bleeding Canker
Horse Chestnut Leaf Miner (Cammeraria ohridella
Oak Processionary Moth (Thaumetopoea processionea)
The caterpillars of the oak processionary moth (OPM) are pests of oak trees where they feed on the leaves. Large populations can strip whole oak trees bare, leaving them more vulnerable to other pests and diseases. However, when disturbed the caterpillars release tiny hairs which can cause a serious reaction including a itching rash, eye irrirtaions sore thorats and breathing difficulties. Bceause of the risk to human health it is a notifiable pest which should be reported using the Tree Alert website or by emailing [email protected]
Phytophthora Bleeding Canker
Bleeding canker is a term for a number of tree diseases that result in dark, sticky fuid oozing from the bark of trees, staining the bark which, if cut away over infected areas, will reveal a reddish-brown discoloured area of tissue. The foliage of affected trees may be pale and sparse and branches may start to die back. Eventually the branch may die and in severe cases the whole tree may succumb. Many of the cankers seen in trees are the result of infection by one or more of any of the large number of species of Phytophthora For instance, the bleeding cankers seen on lime trees (Tilia spp. as illustrated above) are associated with P. cactorum and P. plurivora; these and other species of Phytophthora can occur on a range of trees including Beech, Maples (including sycamore), Oak and Birch. See the entry below for other phytophthora diseases.
NOTE - Horse Chestnut Bleeding Canker, which is caused by a bacterium, is dealt with in a separate entry above.)
Phytophthora diseases (including Ramorum disease)
Phytophthora is a group of 'water moulds', microorganisms which, although fungus-like, are actually related to diatoms and brown algae. There are over 100 different species and are responsible for a wide range of diseases causing extensive damage and death to more than 150 plant species, many of great ecominic andsocial significance. (Potato blight caused by P. infestans led to the Irish Potato Famine that killed about 1,000,000 people).
Phytophthora ramorum causes the death of a wide range of trees including Sweet Chestnut and Oak but its greatest impact so far has been on larch plantations, leading to thousands of hectares of felling around the UK. Suspected cases of ramorum disease on trees or other woodland plants must be reported to the forestry authorities. If you think you have seen ramorum disease on a tree or other forest or woodland plant, please check the guide to identification and symptoms in our Phytophthora manual before making your report.
Other species of Phytophthora are also significant: Phytophthora alni is largely specific to Alder trees and has led to the death of many trees. (See link below.) It is thought that up to a third of British alder trees may be affected, with heavy tree losses are also occurring in alder populations in the borders’ region of Wales, including Herefordshire. Phytophthora lateralis attacks Lawson cypress, as well as juniper and western red-cedar. Holly (trees and hedges)have their own species, Phytophthora ilicis which causes Holly Leaf Blight, characterised by dark blotches on the leaves which then drop prematurely. In hedges it can result in ‘arches’ of defoliation, where the damaged area is widest near the ground. Unfortunately the storey doesn't end there as there are many other trees, shrubs and other plants that can be affected by one or other of the various species of Phytophthora. Click here for an RHS publication that provides a list of plants showing susceptibility or some dgeree of resistance to root rot.
Red Band Needle Blight of Pine (Dothistroma septosporum)
Known as red band needle blight because of the colourful symptoms it shows. It causes premature needle defoliation, resulting in loss of timber yield and, in severe cases, tree death. A disease of conifer trees and pines in particular which, within the forestry industry, is economically important.
Scale Insects
Scale insects take a mulitude of forms, most of which show little remblance to what one usually thinks of as an insect. Sycamore scale, Pulvinaria regalis, is illustrated here
