Hiking is the new sea swimming, and we have a wealth of woodlands across the country to explore. On Today with Claire Byrne, naturalist, broadcaster and president of the Tree Council of Ireland, Éanna Ní Lamhna continued her series on woodland walks, this week taking us to Ulster.

Her destination of choice was the Dumboe Woods in Donegal, within walking distance of two towns, Ballybofey and Stranorlar, and flanked by the banks of the river Finn. It's part of the demesne of the Hayes family and it was an antecedent, Emily Hayes, who undertook the planting of the area circa 1860.

"There's beech trees; there’s giant redwoods; there’s Scots pine; there's oak. There’s hazel, willow, birch and a whole clatter of stuff that are non-native such as horse chestnut, lime, silver fir, Norway spruce. [...] This is very much an amenity woodland, nearly planted as a pleasure place, full of biodiversity; a wonderful place to go and lots and lots of different species of trees."

So, while there's plenty to look up at and revel in, August brings the first signs of autumn and encourages us to rummage around in the undergrowth to uncover another world beneath our feet. Éanna explained:

"What the fungi are are a mycelium; a web of fine strands, if you like, underneath the soil and they live on the nutrients provided by the dead plant material which can be dead leaves, dead timber, that sort of thing. And they work away quite happily breaking down these dead things, releasing the nutrients into the soil and living happily ever after."

And now research suggests that fungi can also help trees communicate – in essence a Wood Wide Web helping the trees channel resources to trees with the most need:

"You might think of this as totally and utterly the realms of science fiction but if you had an MRI scan of the soil underneath a woodland, you'd have the roots of the trees getting smaller and smaller into root hairs practically, and then you have your fungal strands [...] these are a symbiotic relationship – so stuff coming out of the roots of the trees goes into the fungi and nutrients from the fungi [...] go into the trees."

And this relationship extends all over the woodland, Éanna explained:

"The fungal strands go all over the place and the fungus isn't just associated with one tree. Fungus over here on your tree [...] taking stuff out of you, that fungus grows along another bit, comes to another tree with roots, there’s a greater need for more nutrients there. It’s got loads of stuff from you so it’s able to put it into that other tree. [...] These mycelial strands are like a great railway system underneath the soil. So, something that goes in at one point can be withdrawn at another point. "

So research says woodland is an organism, not just a collection of trees. And never mind the fungus feeding the trees, what about getting to gorge on wild mushrooms ourselves? Éanna had this grave advice:

"You can eat every mushroom once. But you know something, you mightn't want to. You can eat berries and you can eat nuts and if they’re not good you get a pain in your tummy. But if you eat a mushroom that isn't right, it attacks your liver, and you mightn't die for a week. So, you can really kill yourself with mushrooms. So if you don’t know what you're doing, if you're not sure, do not do it."

And many edible mushrooms have deadly lookalikes, so being fairly confident won't cut it. This is the perfect time of year for fungal foraging walks with experts:

"It’s really important to go with someone [...] and learn what it is. Do not be asking someone else because you’ll leave out some important details and you’ll get the wrong advice."

You can hear Éanna's full chat with Philip here, and hear more from her series on woodland walks here and here.