Thinning of trees is achieved by removing selected branches from within the tree’s canopy and is usually specified in percentages.
To roughly illustrate, a specified 10% crown thin will remove 10% of the leaf volume of the tree or one branch out of every ten for example.
This allows more light to filter through to underneath areas and can help remove competing branches and overcrowding leading to improved form and shape. This is especially important for fruit trees.
Over-thinning needs to be avoided (usually 20% is the recommended maximum percentage) and can lead to several problems.
- Excessive production of water-shoots to compensate for the loss of too many branches. These shoots grow very fast and make for an even denser tree than before.
- Previously shaded branches can get sun-scald, especially on sensitive species such as the Copper Beech or Japanese Maples. This can lead to cracks forming and bark die-back. Time of year is also an important consideration.
- As with crown lifting, over thinning creates top-heavy ‘lion tailed’ branches that are unsightly and can snap off in high winds.
- Over thinning can shock a tree and especially in older mature trees or trees that are struggling a bit, can lead to the trees decline.
As with all aspects of tree pruning, the correct advice is key to making the right choice to best achieve your objectives.
Want to know how much Tree thinning or Crown thinning costs? Green Industree Tree Surgeons can advise you.