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The Woodland Education Centre
The Heathland Restoration Project
Contents

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Ecological Surveys 1996 - 1998

Summary

Summary points 1-10  11-16  17-18  19-26

The Heathland Restoration Project is concerned with restoring an area of lowland heath in the Woodland Education Centre in Offwell, Devon, from conifer and rhododendron woodland. Different management techniques are being used to identify which is the most appropriate
Clearance of the Heathland Restoration Project Site. left: This former area of dense rhododendron and conifer woodland was cleared to start work on restoring it
as a heathland habitat.  This is the site of the Heathland Restoration Project described in this report.

 

 

 

  • 1.       The Woodland Education Centre is a Forestry Commission site, created and managed by the Offwell Woodland & Wildlife Trust. It covers an area of 50 acres.

    Since 1986, the Centre has been restored from a virtually worthless rhododendron jungle to an area of great ecological significance. A wide variety of different native habitats have been restored.

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Rhododendron on the project site.

 
  • 2.      The site selected for heathland regeneration covers an area of just over 2 hectares on the western boundary of the Centre. It is bounded by woodland to the north, south and west. On the eastern boundary is a cutting and path through the Education Centre, with coniferous woodland beyond (map). It lies at an altitude of approximately 200 metres.
  • 3.      The Heathland Restoration Project site comprises a hillside sloping down from west to east. It has been divided into nine approximately rectangular sections, with their long axes stretching from west to east (diagram). The sections are not physically separated from each other in any way, but are marked out with wooden boundary markers at appropriate points.     
  • 4.      The soil substrate is composed of a thin top-soil, overlying greensand, which in some areas is completely exposed and lacking in top-soil. Soil pH varies from 4 - 5 across the site.
  • 5.      The original vegetation cover on the project site consisted of conifers and broad-leafed trees such as Sweet Chestnut, with an understorey of Rhododendron. This was completely cleared in 1993. (This work was funded by the Countryside Commission.)
Clearance resulted in an explosion of growth from seed banks previously dormant in the soil. (This would have resulted in only partial depletion of the seed bank, many dormant seeds would still have remained.)

The initial regrowth consisted mainly of woodland species which would compete with regenerating heathland vegetation. It was therefore cleared by spraying with Roundup, which is a general purpose herbicide. This rendered the entire project site bare of vegetation, so that initially the site was superficially uniform.

Spraying with Roundup.
 
  • 6.         The nine sections demarcated on the heathland site are not uniform in terms of size (diagram), nor in terms of flora, since the sections at the boundaries of the area (1,2 and 8,9) will be influenced by adjacent woodland. This may affect both microclimate and soil conditions. These sections are also likely to have greater numbers of tree seedlings becoming established, due to proximity to the woodland. The top (western end) of each section may also be influenced by the deciduous woodland beyond the narrow path forming the boundary.

    With these limitations in mind, different management regimes were assigned to each section with the aim of successfully promoting heather growth in one or more sections. To compensate for their small size and the influence of the woodland boundary, sections 1 and 3 are duplicates of the same management regime, as are sections 2 and 4.
  • 7.        Management Details.
Action>> Spring Brushcut Summer Brushcut Autumn Brushcut Roundup Herbicide Garlon & Kerb Handweed Initiated
Section No. - - - - - - -

1

- -

+

- - -

1995

2

+

- - - - -

1995

3

- -

+

- - -

1995

4

+

- - - - -

1995

5

- - - - - -

1995

6

+

+

+

- - -

1996

7

+

- - -

+

-

1996

8

- -

+

+

- -

1996

9

- - -

+

-

+

1996

 

  • 8.        Methods. The vegetation on the heathland site was surveyed annually in July from 1996 - 1998. The 1996 survey acted as a base-line survey of vegetation initially regenerating on the site (after the two prior clearances in 1993).

    T
    he site was surveyed by carrying out a belt transect across the centre of the site, encompassing all sections from 1 through to 9. Additionally, in 1997 and 1998, random samples were taken within each section. Sampling yielded data on the species present, their abundance ( % cover ) and maximum height. This allowed comparisons to be made between the vegetation in sections under different management regimes, as well as showing overall changes in the site vegetation with time.
  • 9.         Two different methods were used to survey the site. A belt transect was carried out every year from 1996 to 1998. Random quadrats were also sampled in 1997 and 1998. The results obtained using the two different methods were in many cases quite different from each other. This illustrates the need to use the same method of sampling when comparing results from different areas or over time. The random quadrat data was judged to be the most accurate. The two sets of data taken together provided a good picture of vegetation on the site.
  • 10.       A total of 90 species were recorded on the project site over the period 1996 - 1998.  Most of these species were rare on the site.  

 

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Ecological Surveys 96 - 98
Contents