Crown thin by removal of a proportion of the small secondary live woody growth, taking care to retain the framework branches, to reduce the leaf area of the canopy by a given percentage. The aim of crown thinning is to produce an even canopy of foliage on a well spaced, balanced and sound framework of limbs and branches, typical for the species or variety of tree.
Advanced Tree Services (ATS) advise crown thinning works to be undertaken when an even density of foliage needs to be secured with a balanced structure, and to reduce the weight of the crown to avoid stem failure. The overall shape of the crown will not be altered, reduced or reshaped as with a crown reduction.
The percentage of material to be removed will not exceed 30% In line with BS3998:2010 so as to not significantly alter the leaf bearing structure and architecture.