[Talk-GB] natural=heath

[David Groom]

I have came across a similar issue where areas of mainly grass, but with 
some gorse bushes, on chalk downland had been changed to natural=heath, 
when I contacted the mapper about it he said something along the lines 
of, "well I've seen it done like that elsewhere"

David



------ Original Message ------
From: "SK53" <sk53.osm at gmail.com>
To: "Talk-GB at openstreetmap.org" <talk-gb at openstreetmap.org>
Sent: 09/01/2017 11:53:51
Subject: [Talk-GB] natural=heath

>Somehow I have been oblivious to the fact that large numbers of 
>polygons tagged natural=heath have been added over the past few months 
>to OSM.
>
>I only noticed these when looking at old traces on the new GPX trace 
>overlay. Specifically I noticed them on the Snowdon range extending 
>beyond Moel Eilio.
>
>I have now reviewed my photographs taken in 2010 for the countryside 
>extending N of Moel Eilio to the pass between Foel Goch and Moel 
>Cynghorion. As it was a beautiful day the photos also provide valuable 
>interpretive evidence not only for the rest of the Snowdon range, but 
>for the Northern Glyders, Mynydd Mawr and the Nantlle Ridge.
>
>Both in detail and in long view the vast bulk of this countryside is 
>unimproved grassland, which is why it is used for sheep farming and not 
>grouse moors. There appears to be a small patch of heather moorland 
>beyond the forestry to the N of Moel Eiio, and possibly a patch in one 
>of the valleys to the E.
>
>In addition to reviewing my own photos I have also checked the same 
>areas against the Phase 1 habitat survey carried out by the Countryside 
>Commission of Wales roughly between 1980-1995. This also shows the vast 
>bulk of the area as being acid grassland, albeit with some small areas 
>of mosaic grassland and heath. Unfortunately I cannot show this 
>analysis because I obtained the data under an distinctly non-open 
>licence and need explicit permission from Natural Resources Wales to 
>publish the data.
>
>This is not to say that the use of tag natural=heath is wrong. Many of 
>the areas which have recently been mapped as natural=heath can also be 
>described as moorland or rough grazing depending on context (upland or 
>coastal).
>
>The more usual use of heath, certainly within communities of 
>naturalists, conservationists and ecologists, is for habitats dominated 
>by ericaceous (members of the heather family) shrubs & sub-shrubs: 
>i.e., heather, bell heather, heaths, bilberry, crowberry etc.
>
>The phase 1 habitat manual (phase 1 is the basic ecological survey 
>technique developed by the Joint Nature Conservation Committee, JNCC) 
>states:
>
>"Heathland includes vegetation dominated by ericoids or dwarf gorse 
>species, as well as 'heaths' dominated by lichens and bryophytes, dwarf 
>forbs, Carex bigelowii or Juncus trifidus." (p. 41, 2010 revision)"
>
>Personally, I would prefer that we stick to a definition similar to 
>this one. There is not likely to an entirely straightforward 
>correspondence with Phase 1 as some upland heather moorland may get 
>mapped in Phase 1 onto other habitats, particularly if underlain by 
>large quantities of peat.
>
>The reasons for this are:
>Habitats are different. Habitats as different as these should be tagged 
>differently. Upland and coastal unimproved grasslands are very 
>different habitats to heather moorland and very very different from 
>rare lowland heaths. Just the range of birds one encounters will be 
>different. On the former I expect to see Meadow Pipits, Wheatears and 
>no Red Grouse. Lowland heaths in Southern England are habitats for 
>quite rare birds: Nightjars, Woodlarks, Dartford Warblers.
>Terrain underfoot is different. There is a massive difference between 
>walking though knee-deep heather in places like the Rhinogs or the Mull 
>of Kintyre, the lovely turf on the ridges N of Snowdon, or tussocky 
>coastal grassland. We should be capturing such things.
>Visual differences. The image of the country is different. Most 
>apparent when heather is in bloom.Landuse differences. Most obviously 
>sheep grazing versus grouse moor, although sheep may still be 
>encountered on the latter.
>Obscuring rare natural areas. Genuine lowland heath is a rare 
>phenomenon in Britain and requires great conservation effort. Extension 
>of the natural=heath tag to cover other things means that identifying 
>these special areas using OSM will not be possible.
>I reviewing the extent of current use of natural=heath I may already be 
>too late in preventing an extension of its meaning to cover more or 
>less all non-intensively farmed areas which aren't wooded. 
>Notwithstanding this I would like to canvas views from other mappers. 
>If the current usage of the tag is deemed to be the suitable one then 
>we need to develop additional tags which allow the recognition of all 
>the features I mention above.
>
>Regards,
>
>Jerry
>
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