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Caithness Field Club Bulletin |
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Badryrie Wood - 18 Years on (by Ken Butler) Introduction On 9th July 2002 Ken Butler and Chris Ferriera visited the site to make an assessment of its conditions and prospects 18 years after it was enclosed. A formal report of the visit was prepared (2) . The Surrounding Area The near landscape is a patchwork of peat moor, grassland and bog. The peat moor is a typical Caithness type of vegetation called Callunetum with dominant heather (Calluna) accompanied by occasional green-ribbed sedge (Carex binervis), wavy hair-grass (Deschampsia flexuosa) and bell heather (Erica cinerea). The grassland is variable, with Yorkshire-fog (Holcus lanatus) and sweet vernal-grass (Anthoxanthum) dominating the drier parts and purple moor-grass (Molinia), tufted hair-grass (Deschampsia cespitosa) and sweet vernal-grass dominating the wetter parts. The boggy areas are dominated by rush species grading to common sedge mire (Carex nigra) in places. The trees outside the enclosure, on the west side, are old (50 year?) willow hybrids, probably Salix cinerea ssp. oleifolia x S. aurita = S. x multinervis. On the east side are 4 old (50 year ?) birch trees and one other fairly pure willow Salix cinerea ssp. oleifolia. There are no young trees or low shrubs outside the enclosure. In the Enclosure The enclosure is populated with many more trees that are in better condition, with an understory of small shrubs and a richer ground flora. There are birch trees of the Highland Birch type (Betula pubescens ssp. tortuosa). This is a small shrubby tree without a distinct trunk, with small leaves and strongly pubescent young branch shoots. Some are old trees (maybe 50 years old) and others are distinctly younger and smaller, having presumably grown up after the enclosure. There were no young seedling birches seen. The birches cover around 15% of the area of the enclosure. The other trees present in the enclosure are hybrid willows. Most of them are Salix x multinervis, but one is a hybrid Goat Willow, probably Salix caprea x aurita. None of them seem young enough to have arisen after the enclosure and no seedlings or suckers were prominent. No alder was seen despite the 1984 article (1) stating that it was present. There are three types of ground flora. · The Callunetum which is common outside the enclosure continues to flourish inside in an area that has few trees. It is not obvious whether the trees have avoided this area because of its nature, or whether the ground flora persists because there are no trees. The most noticeable feature is that the internal Callunetum has many plants of creeping willow (Salix repens) which does not occur in the external Callunetum. It is interesting that the creeping willow is unusually small-leaved and a few plants were covered to an unusual degree with a silky appressed indumentum of shiny silver hairs. This area also carries several shrubs of pure or hybrid eared willow (Salix aurita) and a few plants of the hybrid willow S. aurita x repens. The Callunetum covers about 30% of the enclosed area. · There are areas of ground covered by the Great Wood-rush Luzula sylvatica which is absent from the ground outside the enclosure. This plant covers about 10% of the enclosed area. · The remainder of the area has a grassy
ground flora. Much of it is dominated by Yorkshire-fog (Holcus
lanatus),common sorrel (Rumex acetosa) and heath bedstraw (Galium saxatile)
with some wavy hair-grass (Deschampsia cespitosa). One flushed sloping
area is richer, with meadowsweet (Filipendula ulmaria), wild angelica
(Angelica sylvestris),marsh thistle (Cirsium palustre), marsh horsetail
(Equisetum palustre) and Germander speedwell (Veronica chamaedrys) and a
small patch of tamarisk moss (Thuidium tamariscinum). There is one rose
bush, around 1½ metres high, which is the glaucous dog-rose (Rosa caesia
ssp. vosagiaca). · To allow new birch trees to become
established and grow. The vegetation seen can usefully be compared with the National Vegetation Classification (NVC) (3). Outside the enclosure the peat moor is of type H10 in which heather (Calluna) is strongly dominant and regular muirburn keeps it in that state. Inside the enclosure the heather is taller and willow shrubs are scattered through it. It has only retained its peat moor character in areas not covered by the trees. At the margins of the peat moor area inside the enclosure dense stands of great wood-rush (Luzula sylvatica) have developed with small quantities of bilberry (Vaccinium myrtillus). This is recognisable as U16 tall herb community and Rodwell (3) comments (vol 1 p290) that this is a recognised precursor to type W17 woodland. It may therefore be that the heather cover is being replaced by woodrush as part of its transformation to new woodland. However, since the ground flora was not mapped at the beginning of the project, this can only be speculation. The grassy vegetation outside the enclosure is recognisable as the calcifugous grassland U13 with variations according to local drainage and the presence of minerals in the groundwater as it emerges from the fissures of the Old Red Sandstone. In many areas Yorkshire-fog (Holcus lanatus) becomes dominant in a more mesotropic (calcium-rich) variant. Inside the enclosure this type of grassland predominates under the tree cover with the inclusion of considerable amounts of common sorrel (Rumex acetosa). The enclosure contains a flora in transition and it is not to be expected that the woodland as a whole will correspond to one of the mature woodland types of vegetation in the NVC. Northern birchwoods are usually assigned to type W11 if the soil is mildly calcium-rich and to type W17 if it is calcium-poor. Both of these are fundamentally oak-and-birch woods; in the North the oak is absent even from mature woods either because it is climatically unsuitable for them or because they have been felled and the seed bank has been eliminated. In this enclosure the wood is too immature to contain oak even if seed were available. If the wood were of type W17 then it would predominantly have indicator species such as the moss Dicranum majus, wavy hair-grass (Deschampsia flexuosa), bilberry (Vaccinium myrtillus) and the hair-moss Polytrichium formosum. It is specifically the areas that have not developed tree cover that have some of these species, and they are infrequent or absent in the wooded part. If it were of type W11 then it would have wood-sorrel (Oxalis acetosella) as an important indicator species; this is not present, but that may be simply a matter of lack of local seed. Other species present are supportive of it being W11 including Germander speedwell (Veronica chamaedrys), sweet vernal-grass (Anthoxanthum odoratum), heath bedstraw (Galium saxatile), tormentil (Potentilla erecta) and tamarisk moss (Thuidium tamariscinum). However, neither W11 nor W17 normally have grey willow (Salix cinerea) as a component. Type W4 is a birch woodland with significant willow and the type W4b matches quite well. Rodwell (3) comments (vol 1 p75) that W11 is the most similar birch-dominated community to W4. The ground flora indicator species for W4b include soft-rush (Juncus effusus), tormentil (Potentilla erecta), wavy hair-grass (Deschampsia cespitosa), Yorkshire-fog (Holcus lanatus), marsh violet (Viola palustris), marsh thistle (Cirsium palustre) and sharp-flowered rush (Juncus acutiflorus), all of which are present. The woodland thus seems destined to be of type W4b/W11. Future Prospects The seed bank for further development is a long way off - perhaps Latheronwheel is the richest source 9 km away. Insofar as the purpose of the enclosure is to observe the development of the site naturally after enclosure, it is recommended that no extra species be artificially introduced. There is clear evidence of the presence of both roe deer and red deer outside the enclosure, though not in big numbers. The fence needs to be maintained to prevent their entry and it would be most unwise to open the area for grazing. There are two significant issues that
might be answered by a little further work: Conclusions References |