Matt Butler, Visitor Ranger

As I was working in the Park this summer, I overheard a conversation between two kids, which really made me chuckle. They were just getting off the coach in the Park as they arrived for their school trip of activities on the lake at Nene Outdoors. One kid looked across Coney Meadow and said, “It looks like the Sahara dessert!” The other replied, “No it’s more like my mum's toast!” You could see why they said that! 

This summer at Nene Park we really felt the heat and drought. The sunshine was amazing and the weather beautiful for picnics and BBQs but with temperatures hitting 40'C and even higher in some places, it has been one of the hottest and driest summers on record which has had a huge effect on wildlife, plants and trees in the Park 

Around the hottest days this summer, three big oak tree limbs broke off in Bluebell Wood and half a tree snapped off near Milton ferry Bridge. This is known as 'summer branch drop'.

What is 'summer branch drop'?

'Summer branch drop' is a term that describes the failure of mature tree branches with no obvious cause during the summer period. It has been recorded to occur after the onset of a heavy rainfall or a prolonged dry spell, which we certainly saw a lot. Even though there is the potential that this combination of weather is related, it has not been confirmed as the main cause.

'Summer branch drop' mainly occurs in trees like oak, beech, ash, sweet chestnut, horse chestnut, sycamore and eucalyptus but we also find it in English elms and poplars.

The branches most likely to fail during this period are the longer over-extended limbs, usually 10cm or more in diameter. These are limbs that usually extend to or beyond the rest of the crown of the tree.  As the trees get new leaves at the start of the summer, the added weight of this newly-developed fresh foliage and fruit, as well as surface water from the rain, potentially results in added pressure onto the branch structure. This may then lead to branch failure.

At the fracture point, the wood may appear sound. However, it’ll usually be at right-angles to the axis of the branch, cutting across wood fibres where it will fail. Even though the wood may appear fine, branches may have an internal defect or a historical earlier weakening that isn’t visible. As well as these; stress to the tree, internal cracking and previous storm damage may also count as factors. 

The Park Management Team is always vigilant, undertaking regular tree surveys and looking out for signs that branches may fail but often it is extremely difficult, or next to impossible, to discover this before it happens. We continue to do all we can to keep the public safe and protect the trees in the Park from further damage. 

...but what will more frequent hot, dry summers mean for the future of our trees?