We don't need any subtags to grassland=* which only describes the location (continent) of the grassland. This is done by the coordinates.
If it's urban grass, the right tag should be landuse=grass.
Tagging of earth surface should not describe linguistic/cultural regional differences in the first place.
We have some natural (uncultivated) grassland here i.e. in the Rhoen or Vogesen mountain which very little looks like "Steppe" or "Puszta", much more like natural=fell (which is per defintion limited to alpine or subalpine regions above the tree line). --Taunide (talk) 06:24, 10 November 2016 (UTC)
Please don't include Dehesa in grassland. Alternative tags exist: landuse=wood_pasture and meadow=wooded_meadow. Dehesa and other wood pastures are really distinct from both grasslands & woodlands. The simplest thing is to map them separately rather than trying to shoehorn them into existing classifications. Much of management of Dehesa is the regular pruning & cropping of trees whether for firewood or cork. The pasturage also depends on the acorn crop as well as the two stages of grass growth which are dependent on the trees. In appearance, management etc. they have little in common with other grasslands. Also much Dehesa may not have any grass at all. The understorey may be various shrubs: notably Cistus ladinifer or brooms and similar members of Fabaceae. See various documentary photos of Dehesa on Flickr. Far, far, better start a separate article about Wood Pasture in general and discuss the issues. Various books by Oilver Rackham are very useful in this regard. The one situation where use of grassland is where the Dehesa has become relict, and very few trees remain: although there is no guarantee that the area won't be re-planted. SK53 (talk) 20:11, 2 August 2017 (UTC)