Managing trees and vegetation
Trees are a highly valuable natural resource, which support an abundance of species. However, left to their own devices, the branches spread outward across the canal channel, shading the water below.
This can be beneficial in small amounts, helping to create stable temperatures in the canal and also preventing the sun loving fringe habitat from over developing. Observation shows some of the protected aquatics to be tolerant of small amounts of shading so it can be a good natural way to reduce competition from the fringe habitat for them. Where the shading becomes more extensive though, the light that is needed by the plants in the channel for survival, is blocked out completely.
In addition to influencing light levels, trees influence the nutrient levels in the water when they drop their leaves. This continual cycle of organic input enriches the nutrient levels of the water and creates a layer of humus over time. A more nutrient enriched environment with this substrate layer, lends itself to the overdevelopment of more aggressive species, such as some of those in the fringe habitat. Over time, this contributes to the silting up and complete domination of the channel by fringe species.
Safety is also of concern when addressing trees adjacent to the waterways. Where trees reach the end of their life cycle, are impacted by weather events, or are affected by disease (e.g., ash die-back) they have potential to drop limbs and cause harm. For this reason, some trees are selected for complete felling, where it is thought they pose a risk.
As with everything, a balance will be struck with some shading to help control the emergent fringe, but not too much as to prevent growth of the plants below. By ‘siding up', a process to remove those heavier limbs reaching out across the water, more light will be allowed to reach the channel, without removing the valuable trees. Hedges will also receive some management; by laying hedgerows, we promote healthy hedges that do not become sparse or leggy with reduced value for biodiversity.
Last Edited: 30 June 2023