The Woodland Education Centre
Ecological Surveys 1996 - 1998
Summary points 1-10 11-16 17-18 19-26
The Effects of Management
The dominant plant species on the project site were grasses. Initially, Bents (Agrostis spp.) were dominant, but Yorkshire Fog (Holcus lanatus) had overtaken them to become the most dominant species on the site in 1998.
This seemed to be related to brushcutting. The relationship was indicated by the fact that the only areas where Yorkshire Fog was not dominant, were those which were not cut.
non-selective and reduces all vegetation to ground level at regular intervals. This
eliminates competition from species which would grow taller than the grass given time
(Gorse, Heather, tree seedlings). If these are allowed to grow up, they outcompete the
Yorkshire Fog and Bents and prevent them from becoming dominant. (However, they would also
in time shade out the underlying developing heath vegetation.)
ii) Tree seedlings
The most common tree seedlings on the site were Silver Birch (Betula pendula) and Cherry (Prunus sp.). Brushcutting apparently controls their height, but not their distribution on the site. These two species appeared to be in direct competition. Silver Birch was much more abundant, but Cherry grew more rapidly after cutting.
Tree species were becoming dominant in the control section and in time will shade out the shorter vegetation. The only other area of the site where they are likely to be a problem is section 9 which is uncut. The management regime in this section is hand-weeding, so they will be controlled in this way when resources allow.
iii) Indirect effects
|Slender St. Johns-wort (Hypericum pulchrum - left) was widely distributed over the project site initially. It was the fourth
most dominant species in 1996.
In subsequent years it steadily declined in abundance. This may be a direct result of brush cutting, or may be an indirect effect, resulting from increased competition with other species, particularly the grasses.
Timing of the brush cut showed a significant effect only on bluebells growing on the project site as a woodland remnant. The Bluebells appeared to declining sections 2 and 4 which are cut in the spring. The distribution of most other species on the site showed little relationship to the timing of brush cutting.
For an ecological sampling exercise, based on Bluebell distribution in strips 1 - 4 seven years after management on the Heathland Restoration site began, click here
Cutting, whenever it takes place, will have the effect of reducing competition for light and space for a time. This may allow species to establish which would not otherwise be able to compete with the dominant plants. The more frequent the cutting, the more this effect is likely to be exaggerated. This is illustrated by the fact that Section 6, which is cut three times a year, had the highest species diversity on the project site. It was also the only area where annual plants became established.
As a consequence of the frequent cutting in section 6, Heather plants growing in this section had a quite different growth form. They formed very low dense clumps, excluding other species because of the density of their canopy. As a result, Heather may come to dominate in this section in time, because it is likely to outcompete other species through its sheer density.
Continue to points 19-26
Ecological Surveys 96 - 98