Best of the best: Select and mark your future Potential Crop Trees (yellow paint) before the first thinning operation is carried out, as all your attention will be focused on these super trees over the coming years. Photos: Teagasc.
Timely thinning is of critical importance. Here, lines of a Scots pine nurse crop need to be removed before they smother the oak
/
Best of the best: Select and mark your future Potential Crop Trees (yellow paint) before the first thinning operation is carried out, as all your attention will be focused on these super trees over the coming years. Photos: Teagasc.
There are many reasons to plant a broadleaf forest on the farm: timber production, biodiversity, water protection and landscape.
If timber production is a central driver, then timely selective management is a must.
Broadleaf accounts for around 30pc of all Irish forests, with much of it still young and at developing stage.
Early intervention for quality
The early years in the development of a broadleaf forest are critical: you need to select the best quality trees, prune where required and to provide selected trees with sufficient space for vigorous growth.
Without timely selective management, much of the future hardwood timber value will be restricted to firewood.
While the firewood market is an important market outlet early on, the focus should be on the production of sawlogs of sufficient dimensions and quality for planking and use by the joinery and furniture trade.
Essential early interventions include formative shaping, identifying potential crop trees (PCTs), thinning and high pruning.
Formative shaping
The purpose of formative shaping is to grow long, straight lengths of quality hardwood timber. By removing forks or large competing side branches while the tree is still young, you can ‘move’ the crown higher up the tree, extending the length of the trunk.
Young broadleaf trees may fork for various reasons, including exposure, frost and animal damage.
Walk your woodland regularly so that you know when the forking occurs. It is much easier (and cheaper) to shape when branches are still light. This will also give you much better results later on.
Shaping of broadleaf trees can be done in either summer or winter. Avoid shaping in spring or autumn.
Shaping is a straightforward and satisfying operation that results in an immediate improvement in tree form.
How to go about it?
First of all, choose a single straight dominant shoot as a leader. Forks can be corrected by removing the weaker (and crooked) side of the fork.
Also remove large side branches. Light side branches are good and should not be removed.
Shaping should start early, once trees are growing vigorously, usually when they are three to four years old.
It is essential to use good-quality, clean, sharp secateurs. Loppers and a pruning saw may have to be used if shaping is left late.
You usually need to carry out more than one shaping.
Don’t remove too much of the foliage: the tree needs its leaves to grow strongly.
A correct cut is made just outside the ‘rough-barked’ branch collar without leaving a peg.
Potential crop trees
PCTs are selected trees of high quality that are favoured during thinning operations.
Some of these trees will go on to produce the final and intermediate sawlog timber.
PCTs should have good, straight stem form, and decent vigour; they should be disease-free and be evenly distributed throughout the woodland.
Aim for 300 to 500 PCTs per hectare.
When selecting PCTs, you need to view the tree from two sides at right angles to each other. Otherwise, stem defects can easily be missed.
Select your future PCTs before the first thinning operation is carried out. It is a good idea to mark these PCTs permanently (for instance, with suitable paint), as all your love and attention will be focused on these super trees over the coming years.
The other trees you can regard as ‘fill’ and will gradually be removed, providing growing space for the top-quality PCTs.
Thinning
Thinning improves timber value. Woodlands that have not been thinned will have very low commercial value, with most of the timber sold as firewood.
The high stocking density of trees in young broadleaf forests encourages fast upward growth and reduced branch size.
Once the canopy of leaves in the crowns of adjacent trees begin to shade each other, you need to remove the lower-quality trees.
This will provide space for the crowns and roots of the remaining, best trees (your PCTs) to expand and grow.
It also prepares the woodland for later thinning operations.
Timely thinning is of critical importance. Here, lines of a Scots pine nurse crop need to be removed before they smother the oak
/
Timely thinning is of critical importance. Here, lines of a Scots pine nurse crop need to be removed before they smother the oak
The trees in broadleaf woodlands have greater variety in form and vigour than in conifer forests. The emphasis is on the selection and management of quality stems for final-crop trees.
Once the PCTs have been identified and marked, the first thinning can be carried out.
The trees to be removed should be immediate competitors to the PCTs, large malformed trees (wolves) and tall spindly trees (whips), diseased trees and lines of trees to create access racks for timber extraction.
Financial support may be available to carry out a first (€750/ha) or second (€500/ha) thinning operation in a broadleaf forest.
Thinning operations supported under this scheme must have the potential to improve the quality of the trees and must be carried out before the trees reach a top height of 15m.
Read More
High pruning
Once the final trunk length has been achieved by regular formative shaping, you can start high pruning, to produce knot-free, high-quality timber.
Start by removing the lowest side branches, gradually removing branches up the tree as the tree develops. Only PCTs need to be high pruned.
High pruning tends to be initiated after a first thin operation has been carried out.
Our next Talking Timber online event will detail the steps you need to take to ensure quality hardwood timber production.
It will be on Zoom on Tuesday, July 20 at 7pm and will include a series of short informative videos and a live studio panel of experts discussing site selection, early pruning, grading trees by quality and vigour, marking for thinning, harvesting best practice and management grants available to owners.
About 400 people attended last month’s virtual event. The topic “The Business of Forestry – how to sell timber” certainly attracted a lot of attention.