[Talk-GB] Typical plants and features of grassland, heath, scrub and woodland in Britain

[James Derrick]

On 15/09/2021 21:30, Tom Crocker wrote:
> I was wondering if anyone has summarised how to distinguish grassland, 
> heath, scrub and wood and the common plants or features in Britain 
> that help define these for the non-botanist like me.

As you say, there's seldom a single factor which makes a tag obvious, 
however personally, a few factors help:

  * landuse=meadow often has beasts grazing, small sheds
    (building=stable), even quality grass, no signs of regular
    cultivation (e.g. tractor tracks) EXCEPT where it has been cut for
    silage. The surface can seem 'rough' in oblique light due to a mix
    of wild plants. Meadow is often in lower altitude areas, and close
    to landuse=farmyard (easier to tend the beasts). You can often see
    the tracks used twice daily to check the stock.

  * landuse=farmland might not be green (time of year?) and regularly
    has tell-tale tractor tracks showing cultivation. Some crops appear
    like green grass, others are green but 'very rough' - guess at
    brassicas?

  * natural=scrub has small bushes, trees, etc. Not enough to be
    natural=wood, not mechanically planted in lines for landuse=forest.
    Sometimes useful for field margins, or what could be set-aside left
    to grow naturally.

  * natural=heath is usually at higher altitudes where the soil isn't
    good enough for meadow or farmland and population density is very
    low. The hard judgement is when to tag meadow/heath. The high
    altitude areas are easier - few fences/dry stone walls, the odd
    sheepfold, large open areas with peaks. Gorse can appear as spiky
    bushes and does flower yellow for a few months.
    As the land rises and conditions worsen, the probability of heath
    increases in my mind. Does the open area seem cultivated? Does it
    have signs of improvement like land drain marks (also installed as
    prep for landuse=forest though)?
    You might see heath being improved into forest, perhaps where an
    estate has investment from wind farms (land drains, enclosure
    fences, machine planting lines).

Over a county area, it is often possible to see the topography from 
landuse - farmland -> meadow -> forest / heath as the conditions change 
by height.

On a field area, unless you're supplementing with ground truth, species 
is unlikely to be accurate - and crop rotation may well change meadow/ 
farmland/ forest next year.


Oh, and building a very recent top tip for JOSM users Tom was kind 
enough to pass on last week:

  * Install the ShrinkWrap JOSM plug-in https://github.com/ubipo/shrinkwrap
  * map the field boundaries, gates, forest areas over an large area
    creating enclosed land parcels
  * (have a quick check with the cadastral layer for imagery alignment)
  * Add-in untagged temporary lines to close fence gaps - leave untagged
    so validation will pick them up if not deleted.
  * Point at the middle of a field area, double check it is enclosed,
    Shift-Alt-B, Shift-Ctrl-V and the field is mapped.
  * Just remember to check for gaps - the balloon tool can disappear
    like the escaping sea for 15minutes if you don't!
  * Add tracks (grade2 grade5?), power=minor_line, etc last to not
    confuse the balloon tool
    (otherwise fix validation "Way contains segment twice" Errors with P
    to chop off the way surrounding the track).

A chunk of the Scottish Borders N of Berwick Upon Tweed has enhanced 
detail with individual field-by field landcover using the balloon tool 
this week. With practice, it works well.

Happy Mapping,


James
-- 
James Derrick
     lists at jamesderrick.org, Cramlington, England
     I wouldn't be a volunteer if you paid me...
     https://www.openstreetmap.org/user/James%20Derrick
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