The Friends are often asked why so many trees are being felled in the Park. To explain this we looked at three types of tree that, in 2021 are being felled fairly often – Oaks, Plane and Horse Chestnuts.
The two trees in the photos are a Turkey Oak and a London Plane on Marylebone Green. The Royal Parks Arboricultural Officer regularly checks trees with his hammer and metal rod, and when they appear weak a “scan” is arranged to assess the internal structure. Unfortunately, dry summers allow fungus to settle on many trees and, as can be seen in the photos, caused the interior to rot away. Trees like these must be felled, and the Park is always planting new trees to replace them.
There is currently a serious problem with Horse Chestnut trees. Throughout southern England the health of these trees is being severely compromised by a combination of diseases that affect both the leaves (leaf miner) as well as the vascular system beneath the bark that transports water and starch (bleeding canker of horse chestnut). Typically, leaves prematurely brown in mid-summer and the bark cracks, exudes black liquid, and exposes wood to other pathogens such as fungi. See more about these diseases here and here.
Horse Chestnuts have now been living with these pathogens for15 to 20 years; the effect is canopy decline and eventual death and/or colonization of the wood by fungi and consequent branch and eventual stem failure. The Royal Parks has undertaken much work on these trees to mitigate risk over the last few years; many have had crown reductions. They have had to fell a few. They continue to reduce and fell these trees. Many are now in state of advanced decline from which there is no return
Mark Elliott, February 2021