Moors or moorland are English. They are not plains. The following is a quote from Wikipedia
Moorland nowadays generally means uncultivated hill land (such as Dartmoor in South West England), but the Old English mōralso refers to low-lying wetlands (such as Sedgemoor, also SW England).
I can find no reference to "Broad Treeless Plains" located anywhere in the Highlands. What follows is the opening sentence to "Scottish Highlands" from Wikipedia.
The Scottish Highlands (Scottish Gaelic: A' Ghàidhealtachd, Scots: Hielans) include the rugged and mountainous regions of Scotland north and west of the Highland Boundary Fault, although the exact boundaries are not clearly defined, particularly to the east.
See the related link for more detail and photographs.
The northern part of Scotland is commonly referred to as the Scottish Highlands.
grampian mountains
A treeless zone is called Tundra.
A Highlander is a Gaelic person who lives in the Highlands of Scotland. This term is used to describe Scottish farmers and herders.
The fishing port on Loch Inver is called Lochinver.
It is in a lake called The Loch Ness in the Scottish Highlands.
It is called a Kilt, the traditional dress of men and boys in the Scottish Highlands since the 16th Century
The only bird found in Scotland is called the Scottish Crossbill, (which looks like a Common Crossbill) which is found in the pine forest's of the Scottish Highlands.
Scottish crofts were often rooved with turf, sometimes over a layer of thatch.
The prairie or great plains. In Africa it is called the Savannah or veld.
Their official home in Scotland is called The Palace of Holyroodhouse , but they also have a home in the Highlands called Balmoral Castle.
A small farm in Scotland is typically referred to as a "croft." Crofting is a traditional form of land tenure and small-scale food production in the Scottish Highlands and Islands.