An extract from the Tidy Towns Handbook

Choosing the right tree species

When planting new trees in towns and villages, there is a wide selection to choose from. Both native and introduced species can be suitable for urban settings. Generally, it is preferable to use native species, such as oak and alder, on the fringe of settlements as they blend well with the rural environment and create a more natural, informal effect as well as promote biodiversity. Knowledge of what grows well on similar sites nearby is a good guide. Some introduced species, especially beech, chestnut and lime, can also be suitable on the fringe of settlements or where required to retain local character. Other introduced species are more suitable for planting within the urban area, in the streetscape, green areas and other public spaces.

Some introduced species may endure exposed coastal locations better than natives, such as the evergreen oak (in areas not liable to severe frosts). Trees that form shallow, surface roots, such as ornamental cherries, can disrupt footpaths and paved surfaces and are best suited to planting on open spaces and green areas. Where trees are planted to create an avenue effect along approach roads and other transport corridors they should be of a single species at a consistent spacing along a route.

Other factors to consider:

• Sufficient space available for root and crown spread at maturity. Roots spread beyond the branch area of the tree with most roots found in the top 45cm of soil and most absorbing roots found in the top 15cm of soil.

• Many Irish place names are associated with or derived from trees and this may be reflected when choosing tree species e.g. Glenbeigh, or in Irish, Gleann Beithe, means valley of the birch trees

• The future height and width of a tree should be considered to ensure compatibility with the scale and character of a space and surrounding buildings at full maturity.

• Colour: Trees with distinctive coloured foliage such as purple hazel and copper beech, variegated maples should be used sparingly as the vibrant colours can appear over-whelming. Rows of trees with crimson leaves should usually be avoided as they
can be visually oppressive while trees with variegated foliage often appear gawdy and unnatural. Trees of strong individual character (e.g. copper beech) are best used as specimens with plenty of space around them.

• Seasonal interest: select trees that can bring year-round interest, i.e. trees with attractive bark, vibrant autumn leaf colour, flowers, catkins or berries, and evergreen species in appropriate locations.

• Fruit, berries and nuts: Trees such as horse chestnut, hawthorn, mountain ash and whitebeam, all produce attractive displays of fruit or berries. Although highly suitable in green areas and parklands, fruit-bearing trees may not be suitable in streets or in
pedestrian areas for safety and cleansing reasons.

• Trees are subject to an increasing number of pests and diseases. Avoiding over reliance on a narrow range of species will limit the impact of these threats. The resilience of our tree population can be enhanced by increasing the diversity and variety of new trees planted. However, where the same type of tree species creates an avenue or clearly defined group within part of a street, new and replacement trees should be of the same or closely matching species in the interest of visual continuity.

• Use large canopy trees wherever space allows. Large-growing tree species confer much greater environmental benefits to urban areas than small trees

• Wildlife and biodiversity value – many trees, such as lime, sycamore, horse chestnut and willow provide excellent bee forage.

Some key points to remember when planting

• Do not let the roots of bareroot trees dry out in transit or on site. Keep them wrapped in plastic or covered with moist earth.

• Make sure the planting hole is big enough to take the roots fully spread out.

• Keep the ‘soil mark’ at the base of the stem at ground level.

• Always water the plant immediately after planting.

• Staking is necessary for any newly planted tree, over 2m to prevent wind-rock and movement of the roots which can slow down establishment.

• A double stake is used for staking containegrown and root-balled trees. Two stakes are inserted opposite each other and secured to the trunk by long ties or a timber crossbar and tie. This method is also useful on windy sites.

• An angled stake is used for trees planted on slopes. Drive a stake in before or after planting at a 45-degree angle, leaning into the prevailing wind.

Aftercare of newly planted trees

• For a tree to become established, a maintenance programme should be followed for at least the first two growing seasons, and
ideally for five years after planting. It can be based on the following;

• Watering – carried out regularly during the first two growing seasons. There is often a dry period from April to June and many
newly planted trees die at this time through inadequate watering. During prolonged dry weather, the soil around young trees should
be soaked thoroughly at least every week. For semi-mature specimens continue deep watering for five years after planting.

• A single stake is the standard method for staking bare-root trees, with the stake inserted before planting. The stake should be
about one-third the height of the tree and is inserted on the side of the prevailing wind so that the tree is blown away from the stake.

• Tree stakes and ties should be checked regularly. Tree ties may need adjustment where they have become too tight, loose stakes should be firmed and broken ties replaced as soon as possible to avoid damage to the tree. Ties and stakes should be removed after two or three growing seasons, or once a tree is stable.

• Control weed growth keeping a circle around young trees, for an area of at least 1 metre in diameter, clear of grass, weeds, or other plants. This reduces competition for moisture and nutrients and also helps to protect tree trunks from lawnmower damage. Applying 50-100mm of mulch will keep soil temperatures cool, retain water, and discourage weeds. Top-up and replace mulch as
needed.

• Apply fertiliser if absolutely necessary. Never fertilise stressed trees.

• Remove dead or injured branches immediately

Formative pruning:

• Young, immature trees benefit from pruning in their formative years. This should be carried out in accordance with good arboricultural practice.

• It involves removing crossing branches and potentially weak forks to encourage a good natural shape and reduce the need for major pruning when the tree is mature.

• Once established, the requirement to prune trees should be minimal, to remove diseased or dead branches or carry out crown lifting.

• The branches of wider canopy trees can be gradually removed, ideally over the first 6-10 years, as the trees grow taller to lift the crown and provide an eventual clear stem of 2.5m in pedestrian areas, 3m on cycleways and up to 4.5m on streets and vehicular routes.

• All pruning should leave trees with a well-balanced, natural appearance.

Care of established trees

Old, mature and established trees significantly contribute to the unique character and identity of a landscape setting and often hold a special place in the hearts of local people. For this reason, they require careful management to ensure their longevity. While the majority may require little or no intervention, the following are considerations in their management:

Protect tree bark from damage: Avoid using weed trimmers or lawn mowers around trees which can cause damage to the bark. Hand-pull weeds instead or mulch the area around the base of the tree to avoid this problem. Alternatively leave longer grass
around established tree groups to reduce the amount of grass cutting. Do not fix signs, flags or other items to the trunks of trees as nailing anything into a tree is intrusive and every wound creates a potential entry point for decay • Disease: Be vigilant for any signs or symptoms of disease, stress or decay and, where necessary, seek appropriate advice from a qualified arborist.

Avoid planting at the base of trees: The practice of planting annual bedding plants or other planting at the base of trees is discouraged, as the root zone of the tree is disturbed annually by cultivating the soil and digging planting holes. Bedding plants also compete with the tree roots for air and moisture. Built edges/ planter walls around trees are also discouraged as building up soil around a tree can suffocate its roots and cause a tree to decline.

Ivy on trees: Ivy provides a sheltered habitat for a range of wildlife and is a great source of autumn nectar for insects and late winter fruit for birds. It is not parasitic and does not directly affect the health of the trees it climbs. However, where ivy has taken
hold on young, weak or mature trees, it may compete for water and nutrients and suppress healthy growth. The density of its bushy growth can obscure cavities or defects from view and increases the tree’s vulnerability to wind damage. In these limited situations, removal of ivy may be deemed necessary for risk management purposes. Ivy should not be removed as a matter of course. It is a native plant and woodland species.

Removal of sucker growth: Some trees such as limes are prone to sucker growths that appear from the root system at the base of the tree. This can detract from the health of a tree as energy is put into producing these shoots. On roadside trees, suckers can be a visibility hazard for road users. Sucker growth should be removed as part of annual maintenance.

Pruning: Older trees do not tolerate pruning as well as younger trees and substantial or unnecessary pruning should be avoided. No branch should be removed without a good reason. Seek the advice and services of an insured tree care professional for large pruning jobs, hazard trees, and insect or disease problems. Non-professionals should never prune near utility wires.

Topping of Trees: Do not top trees to reduce height as this is not good arboricultural practice. It causes large wounds,
exposing trees to decay pathogens and causing their long-term decline. A topped tree is an ugly tree, disfigured even when it
regrows as well as being potentially unsafe. Regrowth resulting from ‘topping’ will often be denser than the original crown and
be weakly attached to the branches it develops from.

Thanks to Dr Christy Boylan who has prepared this piece to support groups with regard to the proper planting, care and maintenance of trees, which are one of our most valuable assets.

Piece taken from the January 2023 Tidy Towns Newsletter.