Tree Pollarding

POLLARDING 

There are a few reasons for choosing to pollard trees. It is an effective way of reducing the amount of shade cast by trees, to thin the crown thereby increasing air circulation, it helps keep trees a comfortable size for their local environment, it may be necessary to shape a tree for design purposes and to prevent trees from touching overhanging electricity or telephone lines.

A number of different species of trees can be pollarded on a regular basis and in some cases it can be an effective way to rejuvenate a tree and to prolong its life. 

Pollarding can be used on many trees including the following:

ash, lime, elm, oak, beech, poplar, eldar, london plane, fruit trees, eucalyptus and sweet chestnut.

It is usually best to carry out any pollarding during the Winter months when the deciduous trees have shed their leaves,and the tree structure is more noticeable. The lower level of tree sap during this season means that less stress will be caused to the tree and it is also less likely that a tree will suffer infection from Insects or fungi during the Winter as both of these threats are dormant.

There are some exceptions to this rule however for example walnut prefer summer pruning and some fruit trees produce more abundant and better fruit if pruned in the summer. Consult a qualified arborist from Arborlife if in any doubt. 

It is also worth noting that trees within conservation areas may well have Tree Preservation Orders (TPOs) on them. It is worth checking with the local authorities before you would like the work to be undertaken and the relevant permission should then be sought either directly by yourselves or by Arborlife on your behalf.

Pollarding is usually done annually and should be done at least every few years to avoid potential problems

Trees may be pollarded as soon as they have reached the desired height and the form can then be chosen.

Usually when a tree has been pollarded, four or five main branches (cut to the desired length) will be left on the stem from which thinner ones will soon grow.

To maintain a pollard these smaller branches should be cut back to the original pollard cuts. In some cases where some leaf cover is required some branches may be left and others cut back to a side stem.

BEFORE POLLARDING

Pollarding is a pruning technique used for many reasons, including:

• Preventing trees and shrubs outgrowing their allotted space
• Pollarding can reduce the shade cast by a tree
• May be necessary on street trees to prevent electric wires and streetlights being obstructed

These are a few of the plants it can be used on:

• Ash
• Lime
• Elm
• Elder
• Eucalyptus
• London plane
• Oak
• Some species of Acer 

Pollarding a tree is usually done annually, and would need to be carried out every few years to avoid potential problems. This usually involves hiring an arborist, so can be expensive. Why not consider the following before pollarding:

The best time for pollarding many trees and shrubs is in late winter or early spring. However, bear in mind the following:

• Avoid pruning Acer species in spring when they are prone to bleeding sap. Summer can be a suitable time to pollard. However, the new growth may be poor as a result of the scorch, drought or heavy shade cast by neighbouring trees
• The least favourable time for pollarding is the autumn, as decay fungi may enter the pruning cuts

Young trees

Once young trees or shrubs have reached the desired height, you can begin to pollard them. This involves choosing a framework:

• On a shrub, this might be one stem cut to a metre high – a mass of stems will grow from the top
• With a tree, it is more typical to leave a trunk supporting three or five branches – these branches are cut back to a desirable length and the twiggy growth appears at these ends

Initially, the new branches are held weakly in place as they grow rapidly from underneath the bark, rather than from within the tree. As the wood lays down annual growth rings, the union strengthens, often forming a thickened base where the shoot meets the trunk. Over a number of years, a swollen 'pollard head' forms where new shoots grow each year.

AFTER POLLARDING