Last Updated on 2 August 2022
Dr Dave Dawson, Wimbledon Park’s local ecologist and environmental scientist, writes about the value of preserving ancient trees in the context of the AELTC’s plans to develop the old Wimbledon Park golf course site involving the removal of around 500 trees.
The AELTC claim that many of the trees to be felled are defunct or growing in the wrong place. Whilst there was quite a lot of inappropriate planting on the golf course, it needs a tree-by-tree assessment to see which can contribute landscape and biodiversity value into the future. It suits their case to count trees that are in the way of their development as being harmful to landscape. An old tree assessed as “unhealthy” may simply be showing signs of age. The most valuable heritage trees are the oldest and it’s their nature to have “defects”. Far from being defunct, they are the future. So, the figures are opaque. That’s why it’s best to focus simply on the losses.
The ancient and veteran tree story is deceptive. They plan to protect some 25 such oaks, which are indeed the most valuable of the trees on the golf course. We should praise them for this. But there are two difficulties of a focus on just those 25. First, is that there will be attrition in future as trees decline, however carefully we manage the veterans. These losses will not be replaced unless we keep a good number of middle-aged trees (50-200 years of age, the future veterans). They claim that there is a good cohort of trees as future veterans, but there is no documentation, nor details of a plan for succession. Second, is the obvious point that neither a head count nor a canopy area tells us about the actual value of the trees. There should be a detailed plan to conserve a good age profile of trees and no number of new plantings can replace the middle-aged tree losses.
It’s widely acknowledged that the first priority for carbon sequestration is to keep our existing trees and woodlands. This is because these have a carbon store that is released all at once if we lose the tree and they have a big canopy, so an individual tree sequesters carbon at a maximal rate. Conversely, newly planted trees have very little store and a small canopy. So, while trees of every age sequester carbon, replacing old trees by youngsters is the last thing one wants to do for the climate crisis.
The last point is what is a tree? Their schedule includes very few trees with a stem diameter less than 10cm, a girth of around 30cm, which means that they have simply not documented the huge number of young saplings. So, the head counts omit trees that are younger than around 20 years, the most numerous age range. It’s anyone’s guess just how many, but my guess would be around 500. Most of these are in areas where the soils are to be stripped, so most of the uncounted trees are to go. Their headline figures have around 300 trees felled and 750 retained, but the 300 is a gross underestimate because of the missed youngsters. I would guess that there are actually more like 800 trees that will be sacrificed.
