Formative shaping of broadleaf trees
Shaping is the process of removing forks and large competing side branches in order to improve the quality of broadleaf trees resulting in long straight lengths of timber for sale to high value markets. Keep in mind that shaping is not the removal of many side branches.
Growing broadleaves for good quality timber takes active management at particular stages of tree growth. Initially, the emphasis is to source good quality plants with good ‘provenance’ that have a proven record of desired traits; e.g. straightness, vigour etc. The next step is to get trees established and growing actively while controlling vegetation and protecting them from damage by browsing animals etc. Even with optimum management there will be some forked trees in all forests. Forking may be caused by exposure, frost, animal damage, insects or diseases.
If a tree forks, the fork always remains at that height on the tree. Therefore, a fork that is not removed early will remain at that height for the lifetime of that tree and will dramatically affect its value. Along with other on-going management (fence/drain maintenance etc); formative shaping of broadleaves should be an on-going integral part of a broadleaf plantation's maintenance.
Shaping as part of the afforestation grant requirements
It is necessary to have shaping complete at second instalment grant stage for ash and sycamore. If oak and beech are well established and maintained, it may be necessary to shape prior to the second instalment also.
However, on sites where oak and beech are deemed not ready for shaping; the second instalment grant can be applied for with a signed agreement of the owner and forester that shaping will be carried out within a specified time period. Failure to carry out formative shaping within the approved date can result in premiums being suspended.
What to shape
It is not necessary to shape every tree. On a well-established site, many trees will not require any shaping - i.e. they already have one single stem with no excessively large side branches (see grade 1 trees below).
On the other extreme, there may be some trees that are of very poor quality with many heavy branches and multiple forks (grade 4 below). These trees are very difficult to improve and are likely to be removed in first thinning for firewood.
Grade 2 and 3 (illustrated below) are trees that can be dramatically improved with well-timed shaping. Grade 2 trees will only need 1-2 cuts to convert into a grade 1 tree. Grade 3 trees have poorer form and will require more effort to improve.
The Forest Service requires that when shaping is complete, at least 60% of trees are grade 1 and 2. Therefore, an assessment should be made to determine how many grade 3 trees need to be shaped to achieve this number; bearing in mind that getting above the minimum 60% is even better.
Description of stem form categories:
|1||Very good, well balanced tree, straight stem, single dominant leader, no strong competing co–dominants, light branches.|
|2||Good quality tree, not full apical dominance, competing co-dominants, or stem can be slightly wavy, moderate stem straightness, not more than one disproportionately large branch.|
|3||Poor quality tree, poor apical dominance or poor stem straightness. One or more forks, whorls or strong co–dominants. One or more disproportionately large branches.|
|4||Very poor tree, poor apical dominance and very poor or competing stems. Crooked stems. Multiple heavy branching or forking.|
How to shape
Shaping should be carried out using good quality secateurs, loppers and in some cases (if shaping is left very late), a pruning saw. Equipment should be cleaned regularly to avoid the possibility of spreading disease.
- Choose a single straight dominant shoot as leader. Then remove the weaker/ poorer quality side of the fork.
- Remove excessively large side branches only if they are competing with the main leading stem (an ‘excessively large branch’ is one that is larger than half the diameter of the main stem).
Remember: Do not remove more than one third of the foliage and only remove branches that may cause a defect in the future.
The correct cutting technique
At the point where a branch meets the main stem there is a raised and creased area called the branch collar. In order to encourage rapid healing after shaping, it is important to cut the fork or branch without damaging the branch collar.
It is also important to cut close enough to the branch collar so there is no peg. A good clean cut is essential to facilitate good healing.
When to shape
Summer is the recommended period for some species but for practical reasons, many prefer working during the winter when tree form is easier to see and ground vegetation is easier to walk through.
Shaping should not be carried out in Spring or Autumn. See below for optimum timing for shaping for the main broadleaf species:
Best period for shaping
2nd best time for shaping
|Ash||June - Aug||Mid winter|
|Beech||June - Aug||Mid winter|
|Sycamore||June - Aug||Mid winter|
|Cherry||June - Aug||None|
Shaping can be repeated with the aim of having at least half of the trees in your woodland with good form. Ideally, six metres of clear straight stem is desirable. Over time, extendable loppers and telescopic pruning saws will be required.
Shaping is a simple job that, when carried out correctly can dramatically improve the quality and value of a forest crop.