The Cairngorms were declared a national nature reserve (NNR) in 1954, being the largest NNR in Britain. In 2006 Scottish Natural Heritage (SNH) reviewed the Cairngorms NNR, and it was decided that the reserve should be broken up into separate, smaller reserves that reflected existing management units. There now are four NNRs within the core mountain area of the Cairngorms. Mar Lodge Estate, which covers the south side of the plateau and the watershed of the upper Dee has been classified as a national nature reserve since May 2017. The Abernethy Forest National Nature Reserve covers a stretch of land from the plateau down to Loch Garten on the north side of the range, and Glenmore Forest Park, covering a remnant of the Caledonian Forest surrounding Loch Morlich, is also designated as a national nature reserve. The Invereshie and Inshriach National Nature Reserve lies on the western flanks of the range, and extends to the summit of Sgòr Gaoith.