Tree Thinning of the developing plantations
Tree thinning is an important practice for the health of our parks as it helps to improve the long-term development of the trees within our care, diversifies habitats and allows us to maintain trees by removing any that are diseased or pose safety concerns to people or property.
Over 5,000 acres of the 6,000 that we manage is landscaped. Within this over 800 acres are relatively new plantations, with many trees being under 40 years old.
Milton Keynes is a relatively new city and when it was first built it was planted with a lot of trees and shrubs to obtain an instant ‘greening‘ effect. The planners of the city did this to encourage people to move into the new city that, at the time, was one of the biggest building sites in Europe.
While successful in the short term, this strategy for planting was not sustainable. The high-density planting means that trees compete with one another to grow towards the light and, if not managed properly by thinning, the trees will put all their energy and resource into growing upwards. In time this makes the stems weak and ‘leggy’, eventuality starting to bend and blow over - not something we want to happen in an urban setting. By thinning the trees out, we can ensure the best trees are retained and that they have the room to develop into well-balanced trees.
In addition to the concern over safety and longevity of the trees, thinning allows much more diversity. If we left these trees, they will form a dense upper-layer of vegetation. This will block out light to the lower shrub and herbaceous layers which will, over time, cause them to die. We’re finding that as the trees mature a lot of the plantations are now making the transition to young woodlands. Within these woodlands we want to encourage a shrub understory to allow for more biomass to be present in the area and for species such as Hawthorn and Hazel to flourish as they are exposed to higher light levels. Wildlife will also benefit in a plantation that has been thinned. The herbaceous and understorey layer that should develop into scrub and thicket becomes a source of food and shelter for all sorts of wildlife, including small mammals and birds.
During our thinning work, we can also remove weak or diseased trees and, importantly during this time of climate change, we can ensure there is a real diversity of species. This will help us combat the various pest and diseases, for example Ash Dieback, that are associated with warmer climates.
Overall the aim is to create well-spaced and structured woodlands, encouraging a diversity of healthy, well-formed trees. As the plantations establish, they will have received three or so thinning treatments over a 30-year period. The intensity of management will slow down, we’ll focus less on removing the upper canopy trees and start paying more attention to the understorey where coppicing (another management technique) will be used.
The tree management techniques we employ are recognised forestry practices that are implemented country wide. We have highly qualified and experienced tree and forestry managers within our team to undertake the work. We also work closely with the Forestry Commission and have a 10-year tree management plan (with required felling licenses) that is vetted and approved by the Forestry Commission.