How Trees Survive Freezing Temperatures

How Trees Survive Freezing Temperatures

Understanding how trees cope with freezing temperatures is important for planning winter tree care and long term tree management. In the UK, where frosts and cold snaps are common, knowing what is happening inside a tree helps you decide when to prune, protect or remove it.

If you need practical help managing trees through winter across London and the Home Counties, the qualified arborists at Artemis Tree Services can advise, maintain and, where necessary, safely remove or replace problem trees.

 

 Dormancy – trees reduce activity to survive winter

As days shorten and temperatures fall, many trees enter dormancy. This is a controlled reduction in growth and metabolism.

• Deciduous trees shed their leaves, reducing water loss and the risk of frost damage to soft tissues.
• Evergreen trees keep their foliage but slow their growth and reduce metabolic activity.

This dormant phase makes winter an appropriate time for a lot of planned work, such as tree cutting, pruning and lopping or tree maintenance, because stress on the tree can be lower and there is no impact on spring leaf flush.

 

 Natural antifreeze – sugars and proteins in the cells

Inside the tree, cells adjust their chemistry to cope with freezing temperatures. As winter approaches, many species increase the concentration of:

• Soluble sugars
• Certain alcohols and amino acids
• Ice binding or “antifreeze” proteins in some species

These compounds act as cryoprotectants. They lower the freezing point of water in the cells and help control how and where ice forms. This reduces the risk of ice crystals rupturing cell membranes and damaging living tissues such as the cambium and buds.

For long lived trees in built environments, repeated freeze–thaw cycles can still cause damage. Regular inspections and, where appropriate, tree reports and surveys help identify weaknesses before they become safety issues.

 

 Controlled dehydration – moving water out of cells

Another key response to freezing conditions is controlled dehydration.

Trees move water from inside their cells into the spaces between cells. This has two main effects:

• There is less freezable water inside the cell, so there is a lower risk of destructive intracellular ice.
• Ice, if it forms, is more likely to be in the extracellular space, where it causes less direct mechanical injury to cell contents.

Combined with higher solute concentrations, this strategy allows many hardy tree species to tolerate temperatures well below 0°C without widespread tissue death.

 

Bark and wood structure – physical protection from cold

The structure of the trunk and branches also contributes to winter survival.

• Bark provides thermal insulation and protects living tissues from rapid temperature swings.
• Ridges, furrows and air pockets in the bark add further insulating capacity.
• Wood structure itself, especially in older trees, can buffer against extreme cold but may also hide internal decay.

Where there are signs of cracking, decay or previous storm damage, it can be worth arranging a professional assessment. Techniques like tree decay detection – Resistograph can help determine if a tree has weakened internally and is more likely to fail during winter weather.

 

 Supercooling – staying liquid below 0°C

Some tree tissues can supercool. This means water in the cells remains liquid below its normal freezing point because there are no suitable nucleation sites for ice to start forming.

In favourable conditions, supercooled tissues can stay unfrozen at temperatures as low as around minus 40°C. This is more common in small structures such as buds and some fine twigs. Once ice does nucleate, however, damage can be rapid, which is why sudden harsh frosts after mild spells are particularly risky.

 

Roots and soil – how underground parts avoid freezing

Roots are critical for water and nutrient uptake, so protecting them is essential.

• Soil acts as a thermal buffer, keeping root temperatures higher and more stable than air temperatures.
• Snow cover, leaf litter and mulch can add extra insulation, reducing the depth of soil freezing.
• In very compacted or poorly drained soils, however, winter waterlogging and freezing can restrict root function and increase stress.

On sites with valuable or mature trees, structured tree estate management can help balance soil care, drainage and access so that roots remain healthy through winter and beyond.

 

Why winter survival matters for tree management

These natural survival mechanisms mean most healthy trees cope well with typical UK winters. Problems usually arise when:

• A tree is already weakened by disease, decay or poor pruning
• Roots have been damaged by construction or soil compaction
• The species is poorly suited to local climate or exposure
• Extreme weather causes physical damage such as branch or whole tree failure

In these cases, professional intervention can reduce risk and prolong the life of the tree where possible.

Artemis Tree Services provide a full range of services, including:

• Crown reductions, thinning and lifting to reduce wind loading and improve structure
• Tree felling where a tree has become unsafe or unsuitable for its location
• Stump removal and grinding after removal
• Tree planting with species and positioning selected for long term resilience

For homeowners and commercial clients across London and the Home Counties, their tree surgeons can advise on the most appropriate winter and pre winter work for each site.

 

 Need help managing trees this winter?

Understanding how trees survive freezing temperatures is only part of the picture. Putting that knowledge into practice on real sites requires experience, the right equipment and awareness of UK guidance and local authority requirements.

If you would like advice on winter tree safety, pruning, planting or removal, you can:

• Request a free quotation via the Get A Quote form
• Learn more about Artemis’ tree maintenance services
• Contact the team directly via the Contact page