Can you over-pick?
By Daniel Butler, author and forager
There is a common perception – particularly among landowners and managers – that mushroom harvesting is causing serious harm to some forest eco-systems. This line re-emerges every autumn as signs go up saying mushroom picking is banned in a particular area. These are usually backed by alarmist stories in the press claiming commercial gangs of East Europeans are stripping forests bare of mushrooms to sell to upmarket London restaurants. Delicate forest habitats are being devastated in the process (see The commercial harvesting myth — Fungi Forays).
Winter / trumpet chanterelles, hedgehogs and chanterelles gathered in a Welsh wood
(Photo: author’s own)
This is total rubbish – but the myth perpetrators seem genuinely to believe it. And their convictions are, naturally, swallowed hook line and sinker by the press. These responses are yet more examples of British myco-ignorance, but unlike the general public’s fear of ‘toadstools’, a failure to understand fungi among woodland managers is positively detrimental. It hinders environmental and ecological appreciation and with habitats under increasing threat in a crowded world, public ignorance/indifference is dangerous.
Let me start by saying this is no knee-jerk reaction from a passionate forager – it is based on hard science. I will come to this later, but let’s start with the simplest explanation.
The fruiting body is just the tip of the fungal iceberg
(Photo: author’s own)
The popular image of a mushroom is of the fleshy growth protruding from grass, leaf mould or bark. This is just part of the real picture, however. The ‘real’ fungus is the mycelium which lurks out of sight around the year. It only erupts into view when fruiting. The parts we eat are the equivalent of apples or nuts. You would think it ridiculous if someone were to suggest that picking blackberries threatened brambles. The same goes for mushrooms.
There has been very little serious research into the impact of wild mushroom harvesting
(Photo: author’s own)
Let’s turn to science. Given the gastronomic, cultural and commercial importance of wild fungi harvests around the world, there is a remarkable dearth of research into the subject. The exception is a 21-year Swiss study of the impact of mushroom harvesting in a large Alpine forest. This c. 220-hectare (c. 500-acre) wood was divided into 10 metre squares. All mushrooms were picked in a third, just the edible species were picked in the next third and the final tertiary was left untouched as a control.
Here is a truncated version of the abstract:
The results reveal that, contrary to expectations, long-term and systematic harvesting reduces neither the future yields of fruit bodies nor the species richness of wild forest fungi.
Now sceptics can legitimately argue one survey cannot be definitive, but this one is impressive in its length and scope. It’s also all we’ve got.
The only serious study of the impact of mushroom picking suggests it is harmless
(Photo: author’s own)
Nevertheless, when the authorities attempted to ban foraging in The Elan Valley in 2007, although they conceded there was no evidence of damage from mushroom-picking anywhere (let alone locally), they preferred ‘to adopt the precautionary principle’.
This phrase is positively Philistine coming from a charity committed to scientific study and encouraging public engagement with nature. It translates as ‘we have no evidence for our position, but just don’t like you.’
This 20-minute haul (in a now clear-felled conifer plantation) provoked huge criticism
(Photo: author’s own)
Finally, it is worth pointing out that the same ignorance over the impact of picking extends to some fellow foragers. Many social media groups devoted to edible mushroom study and foraging have rules stipulating ‘no shame picking’. Correct identification of an unfamiliar mushroom usually involves collection for study at home with proper reference books and even microscopes and chemicals. Whether you intend to eat or study the impact on the mycelium is the same - non-existent.