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St Jude storm – impact on trees and woodlands and biodiversity bonus

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Forestry Commission figures released today reveal that more than half (64 per cent) of the 100,000-plus woodlands across southern England were likely to have been affected by the St Jude storm in some way but very few woodlands should suffer long term damage.

The figures estimate the impact from the St Jude storm in October 2013 on trees and woodlands ranging from Cornwall to Suffolk. More damage was found between Wiltshire and Kent with little or no damage recorded at the south-west and north-east extremes of the survey area.

The Forestry Commission’s National Incident Management Team organised a survey of over 160 woodlands over two weeks. They were searching for trees blown over or snapped and looking at damage to their crowns to assess overall woodland damage.

Most damaged trees are very likely to be left where they are and will turn in to valuable dead wood habitats for wildlife.

Richard Greenhous, Director of Forest Services at the Forestry Commission said:

"Sadly the storm left behind some personal tragedies but fortunately our woodlands proved resilient. They should readily recover from localised damage without seriously affecting local woodland and timber businesses and there could even be a benefit to wildlife conservation.

“Although around 70,000 woods were affected by the storm, the level of damage within the vast majority of these woods was low. Crown damage was highest at 3.7% of all trees across the storm area, but these trees will recover from that damage.

“One per cent of larger trees across the storm area were blown over, plus another 0.5 % snapped around halfway up the trunk. In hard numbers this could account for around 10 million trees 'lost' from the woodlands as a result of this natural event, but we must remember that more than 650 million remain.

“The trees around and below those that are damaged or will die will compensate for this loss and grow into the gap left in the canopy. During that time additional light will reach in to the forest encouraging ground flora and wildlife in general.

“Windthrown and snapped trees were very thinly distributed across woods so harvesting this material would be uneconomic and most will be left in the woods. By time the woodlands are mature enough to supply timber they should have recovered any lost volume.

“The dead trees left behind by the storm will contribute to deadwood stocks in the forest and this will be a bonus for biodiversity, providing additional food sources and breeding habitats for flora and fauna such as lichens, fungi and invertebrates."

Woodland owners and managers who may be concerned or need help or advice about storm damage to their woodland should contact their Agent or Forestry Commission Area Office.


Notes to Editors

  1. The Forestry Commission works with others to protect, improve and expand our nation’s forests and woodland, increasing their value to society and the environment

  2. In response to the storm The Forestry Commission’s National Incident Management Team organised a survey of woodlands from Cornwall to Suffolk to assess overall woodland damage.

    The team took 2 weeks to survey 165 woodlands in ‘clusters’. A cluster of three woodlands within a 3km radius were surveyed on the same day in a total of more than 50 clusters.

    In summary 64 per cent of the 109,000 woods in the area were impacted, but at a low level. The level of impact was highest in crown damage with 3.7% of trees affected. Windthrow and snap impacted 1.5% of area and trees. The sampling strategy estimates incidences of wind damage across the counties selected with a standard error of 4 - 8 %.

    Although a small percentage in itself, a crude estimate suggests 10 million trees will be 'dead' and approximately 2 million metres cubed of standing timber affected. In the context of an annual UK harvest of 10.5 million metres cubed, it is substantive but it is expected to be recovered before planned harvesting. There will be associated biomass and carbon impacts to go alongside this.

    The damage was mostly spread thinly throughout many woods and was in the main in broadleaved stands. Most wind damaged timber will not be economic to harvest and is likely to remain in the woods. The woods will recover this volume in the main by time of harvesting, so markets should not be detrimentally affected.

    A map showing damage recorded in the clusters is available.

  3. In the UK up to a fifth of woodland species depend on dead or dying wood for all or part of their life cycle. Generally speaking, the greater the volume of deadwood the greater the value of the woodland for biodiversity, such that the amount of deadwood in forests and woodlands is now used  as a key international indicator of the biodiversity of forest ecosystems.

    The Forestry Commission have a Practice Guide: Managing deadwood in forests and woodlands (PDF 2.6MB)

  4. Forestry Commission Area Office contact details can be found here.

  5. Media contact: Stuart Burgess,, 0117 372 1073