Jeremy Ashcroft

Will fruit waste (apple cores, banana skins) biodegrade on the hill? Ryan Thompson, Cambridge

Trail’s mountaineering editor is also author of Britain’s Highest Mountain Walks (Harper Collins). He knows the UK hills better than his own reflection.

Eventually fruit waste will break down and biodegrade, but with the lower average temperatures experienced on our hills, mountains and moors the process involved is slower and takes longer – much longer than most people realise. Banana skins, for example, can take up to two years to break down at sea-level. But up high, on the summits, you can add months and years to this time. A recent survey, by the John Muir Trust, on Ben Nevis counted and removed over 1,000 banana skins in one go! And it’s not just the yellow perils that linger longer than we think. Orange peel, apple cores, paper, and cigarette butts all take a long time to biodegrade. One particular offender is chewing gum – some brands that contain elastomers and plasticisers never actually break down and in theory can last forever.

Visual degradation is the most obvious negative impact of this litter, but it’s not the only issue. Food waste will attract scavenging animals, some of which are not normally resident species. Also, when the material does eventually break down the deposits left tend to enrich and alter the existing soil. These two factors can upset the delicate equilibrium of the special flora and fauna that inhabit our favourite high places. It might seem a bit manky putting food waste in your rucksack and hauling it back out again at the end of your trip, but it’s the right thing to do. An easy-to-reach stuffsack, kept for carrying the waste, weighs nothing and can be emptied and cleaned easily on your return home.