Devon and Cornwall have the mildest climate of any region in England. Gulf Stream influence, high annual rainfall, long growing seasons, and relatively rare frost create conditions where trees grow faster, stay in leaf longer, and accumulate biomass in ways that differ significantly from trees in the Midlands or the South East. Understanding how the South West’s climate shapes your trees is the foundation for managing them well.
Rapid growth and its consequences
In Devon and Cornwall’s mild climate, many tree species put on significantly more growth per year than the same species would in a colder region. A young oak in a sheltered Cornish valley can double its crown spread within a decade. This rapid growth is generally a good thing — it means trees establish quickly after planting and recover well from pruning. But it also means trees can outgrow their position faster than their owners anticipate, and management that would maintain a tree’s size for ten years in Berkshire might maintain it for only five years in Devon.
Atlantic exposure: a different kind of stress
Set against the mildness is the exposure. Devon and Cornwall receive the full force of Atlantic weather systems — persistent south-westerly winds, salt-laden air close to the coast, and intense storm events that periodically cause significant damage. Trees in exposed coastal positions develop in response to prevailing winds: they lean, they develop asymmetric crowns weighted away from the direction of prevailing wind, and they carry less leaf area than the same species in a sheltered position.
This wind-shaping is not a sign of ill-health — it is the tree’s normal response to its environment. But it does mean that the centre of gravity for coastal trees is often displaced, and that the root anchorage may be weighted to one side. When storm winds come from an unusual direction — as they sometimes do — trees that have spent decades anchored against the south-west can fail in conditions that would not trouble the same species in a different setting.
Soil and rooting in the South West
Devon and Cornwall’s soils are highly varied — from the deep, rich red soils of the Exe and Taw valleys to the thin, stony soils over granite and slate on the moors and the sandy soils of the coasts. In thin soils over bedrock, tree root systems are shallower than on deeper soils, which affects storm resistance. High rainfall keeps soils saturated for extended periods in winter, which further reduces root anchorage — the reason that whole-tree windthrow is more common in the South West than in drier parts of England.
Exotic species in the South West
Cornwall and the sheltered valleys of south Devon support species that simply do not survive in most of England: tree ferns (Dicksonia antarctica), Chusan palms (Trachycarpus fortunei), large-leaved rhododendrons, Luma apiculata, and a wide range of other southern hemisphere species. Managing these alongside native oaks, beeches, and ashes requires knowledge of their specific growth habits, sensitivities, and pruning requirements — which differ substantially from standard broadleaf arboricultural practice.
What this means for management
The practical implication of the South West’s climate is that trees here often need managing on a shorter cycle than the same species elsewhere. Regular crown management — every five to eight years rather than every ten — keeps trees at a manageable size, maintains their structural integrity, and reduces the risk of storm damage. It is also almost always cheaper in aggregate than allowing a tree to grow unchecked and then facing a larger, more complex and more expensive operation.
If you have trees in Devon or Cornwall that you have not had assessed in the last five years, it is worth a free site visit. We cover the whole of both counties and are happy to give you an honest assessment of what each tree needs.