So what are “woodlands” exactly? It is important to use clear definitions to be able to make comparisons between different times and between different countries. Currently ten percent of England is covered by woodland. But what does that actually mean? The Forestry Commissions nomenclature can be confusing with “tree cover outside woodland” simultaneously being called “small woods”. So small-woods are not “woodland” and do not contribute to England’s 10% cover. The definitions of Woodland, Small-Woods and Groups-of-Trees are given below.
|NFI Category||Maximum Size (Ha)||Minimum Size (Ha)||Min Width (m)||Max Width (m)|
|Small Woods||0.5||0.1||(or <) 20|
|Groups of Trees||0.1|
Despite not being included in Woodland statistics, Small-Woods, Lone-Trees and Hedgerow trees are important. These distinctions between types of woodland are important when talking about woodland in general and in the Chew Valley.
For mapping purposes the Forestry Commission defines woodland as areas of more than “0.5 hectares with a minimum of 20% canopy cover (or the potential to achieve it) and a minimum width of 20m, including new planting, clear fell, windblown and restocked areas“.
Half a hectare is a patch of land 100m long and 50m deep. That is a proper bit of woodland and it may have hundreds of trees on it.
Note that a half hectare patch of clear felled plantation may have no standing trees on it but it has the potential to achieve more than 20% canopy cover in the future. So the definition is about wood-land and not necessarily about tree-cover.
Also it doesn’t include small patches of woodland less than 0.5 hectares, nor hedges, nor lone trees, these are other categories.
The types of woodland mapped by the Forestry Commission include :
- Mixed, predominately conifer
- Mixed, predominately boradleaved
- Coppice with Standards
- Round trees
- Ground prepared for new planting
- Low density
- Assumed woodland
Small woods are the patches of woods that fall outside the Woodland definition. They are woods that are less than 0.5 hectares but more than 0.1 hectares or less than 20m in width. They may be linear or non-linear. These small patches add up across the landscape.
Groups of Trees
Groups of Trees are clusters of trees less than 0.1 hectares, may be:
- groups of trees within hedgerows
Lone trees may be:
- hedgerow trees
- other boundary trees
- trees in open land
Hedgerows are an important habitat and can store a considerable amount of carbon. Like small woods they might be physically small but they add up across the landscape. We have lost a lot of hedgerows in the last 70 years and we have a poor understanding of their status in the Chew Valley.
“Boundary lines of trees and shrubs over 20 metres long and less than 3 metres in height having a mean width of less than 4 metres at the base. Gaps of up to 20 metres count as hedgerow except if the gap forms a different intervening land use such as a road, track or gate.”
Agroforestry is the incorporation of trees and/or other woody perennials within an agricultural system. It is often seen as a dynamic, ecologically based practice, which offers a diversity of social, economic and environmental benefits. Agroforestry describes a wide array of practices including silvopasture the integration of trees and/or other woody perennials with livestock farming; silvoarable the integration of trees and/or other woody perennials within arable farming systems, as well as hedgerows, windbreaks and riparian buffers.