As some real winter conditions are here, we are in the midst of continuing our conservation woodland management work. Halo clearance of veteran trees, a process where vegetation is cleared in a halo around some of the older trees, continues across the Common. Many of these trees began their life in open areas, developing full crowns with a wide and open branch structure and large limbs forming from low down on the main trunk; after all they did not need to grow tall as there were no competing trees, unlike trees grown under a woodland canopy.
This increased crown biomass combined with age means that these trees are really important in supporting our flora, fauna and fungi. However, when trees that began life in an open area become surrounded by younger trees, they suffer due to a lack of light which can shorten their lifespan by hundreds of years. By improving light conditions, by removing competing vegetation, we hope to maintain optimum conditions, so they can live out their full lifespan and provide crucial habitat for our wildlife.
This winter we have also been focusing on our Holly thinning. Whilst Holly is a native species and important for pollinators and birds, when it becomes extremely dominant across the woodlands, it can have a negative impact. Reducing the coverage of Holly in some areas of the Common woodland will be of great benefit to the overall biodiversity.
The low levels of light that accompany the presence of this dominant and hardy tree greatly restrict the development of a well-structured woodland environment. Woodland should ideally contain a full range and balance of structure and this would including a field layer, shrub layer, understory and the canopy layer. We are not looking to remove all the Holly but instead we are aiming to provide some space for structural variation to develop within the woodlands.
Photo credit: Will Scott-Mends
Image credit (Fig. 1. and Fig. 2.): Green, T., 2009. Stating the obvious: The importance of an open grown tree – From acorn to ancient. British Wildlife, 11(1), p.9.