We have several large Aesculus hippocastanum, Horse Chestnut, in the park next to the house, well we had several, in the last 4 years 2 have gone. First there was disease (Guignardia aesculi a fungal infection) or more probably a pest (since 2002 Cameraria ohridella, Leaf Miner) and then strong winds battered them and weakened they cracked and became unsafe. It’s not uncommon to see these beautiful trees with their leaves fading much earlier in the year now.
Then sudden oak death (Phytopthera ramorum) arrived around 2007, first logged in the West Country. It’s a fungal disease that has caused untold damage in the USAaffecting many species including oak, beech, larch, ash, horse chestnut and sweet chestnut. It also attacks garden plants including rhododendron, viburnum and camellia. Slightly oddly the English oak (Quercus robur) appears to have a high resistance to the fungal infection!
And now it’s the turn of Fraxinus (ash). A deadly and devastating disease, that has reduced the Danish Ash population by 90%, arrived, or was first recorded in February of this year. The Chalara fraxinea fungus causes leaf loss and crown dieback and it can lead to the death of the tree (What to look for ). Ash is estimated to make up about 5% of our woodland, approx 80millions trees, that’s a significant impact if it settles in and spreads. If the pattern follows that of Denmark we could see similar devastation to woodland and forest as that done by Dutch Elm disease in the 70’s.
The forestry commission have recorded cases in East Anglia and Scotland and are taking steps to prevent the disease establishing.
“C. fraxinea is being treated as a quarantine pest under national emergency measures, and it is important that suspected cases of the disease are reported”
What to look for. 8 months on the gov’t have issued a blanket ban on all Fraxinea imports from 29/10/12, too late? Well we won’t know that for a while.
And in case that isn’t enough to concern us then there is also the Asian Longhorn Beetle, Horse Chestnut Bleeding Canker, Acute Oak Death (AOD), Great Spruce Bark Beetle, Emerald Ash Borer, Phytopthera lateralis (mainly affects the ever popular Chamaecyparis lawsoniana) to name a few of the more recent pests, a full list can be found on the Forestry Commissions website