Crown Thinning AcrossSurrey And Kent:Same Shape, Less Density

A thin is specified as a percentage of the crown's density to be removed, typically in the 10% to 30% range, agreed at the site visit based on how congested the canopy is and what the thin needs to achieve. A tree being thinned purely to let more light through a lawn might need less removed than one being thinned specifically to reduce wind sail on a large, exposed specimen.

The figure is a guide for even distribution, not a target hit by cutting a fixed number of branches from one area. The climber works methodically through the whole crown, inner, outer, upper and lower, removing selected secondary and tertiary branches so the reduction in density reads the same from every angle once finished.

Selection follows a clear order of priority: dead, dying, diseased and damaged wood first, then crossing and rubbing branches that are wounding each other, then weakly attached or poorly positioned secondary growth, and finally, if further thinning is still needed to hit the agreed percentage, healthy secondary branches chosen for even spacing rather than convenience of access.

Main scaffold limbs, the primary structural branches that give the tree its shape, are not removed in a thin; touching those would be a reduction or a different operation altogether. Thinning stays confined to the smaller growth that adds density without adding structural shape, which is exactly why the tree looks the same size afterwards.

Thinning a large, mature crown properly means the climber has to move through the whole tree, not just work from one or two anchor points, because uneven access is how uneven thinning happens. In bigger specimens across Redhill and Reigate this can mean a longer day than the equivalent-sized reduction, since the work is spread thin and wide rather than concentrated at the tips.

Where a MEWP is a practical option, good ground access, no overhead obstructions, it can speed up work on the outer crown, but the interior of a dense canopy is still usually reached most effectively by a climber working branch to branch.

Species with naturally dense growth habits, sycamore, some limes, and horse chestnut, tend to need more frequent thinning to keep density down, since they regrow secondary branches readily. Oak and beech carry a naturally more open structure in maturity and often need lighter, less frequent thinning once established.

Ash affected by dieback needs particular care: brittle wood changes what is safe to climb and cut, and on badly affected specimens a thin may not be the safe or appropriate recommendation compared with a more conservative reduction or removal.

Because thinning generates cuttings spread across the whole crown rather than concentrated at the tips, the volume of arisings can be larger than expected relative to the tree's finished appearance. All of it is chipped and cleared as standard, with logs available at £100 per tonne bag and woodchip at £50 per truck load up to 3 tonne if you would like to keep material rather than have it removed.

A tree that regrows density quickly may benefit from a thin every few years rather than treating it as a one-off, particularly where the original reason for thinning, heavy shading or high wind exposure, has not changed. We flag a sensible interval at the site visit based on the species and how the particular tree has responded to pruning before.