A coldwater species, Atlantic salmon prefer summer temperatures above 10C; at 33C, they can't survive. Marine Scotland scientists found that only 35% of Scotland's rivers, which stretch for 64,000 miles (103,000km), have adequate tree cover. Lorraine Hawkins, the river director for the Dee District Salmon Fishery Board, a statutory body, said: These rivers and burns are the nursery grounds for young fish and it's the young fish which will be affected by summer temperatures their feeding and growth rates are affected. If it gets hotter, we will see fish dying. So the Fisheries on the River Dee in Aberdeenshire, Scotland, have planted 250,000 saplings along key tributaries. They plan to plant a million in the Dee's catchment by 2035. And Fishery boards across Scotland have similar tree-planting programs, to provide essential shade to lower water temperatures and protect wild salmon from the worst effects of climate heating.