Sweet chestnuts, conkers, oaks and beech trees
October 2022
At this time of year, as I stand and gaze upon the woodland in front of you, it appears as if decorated in a multitude of bright green baubles. What with this and the nostalgia of roasting chestnuts over fire at Christmas time, I think that the sweet chestnut Castenea sativa trees may signal, I hesitate to say, for fear of getting lynched, the run up to Christmas, or at least the entry into autumn.
It is commonly thought that they were introduced to Britain by the Romans in circa AD 100, to provide a supply of chestnut flour or coarse meal for the legionnaires. The nuts being as high in starch as wheat and twice as high as the potato, it is also the only nut to be a good source of vitamin C. The sweet chestnut, though non-native to Britain, has become a naturalised species and is generally welcomed in the landscape as it behaves much like a native tree as opposed to an invasive species.
Sweet chestnut trees propagate mainly by seed, which are their nuts, a nut merely being a seed with a hard shell. All nuts are seeds, but not all seeds are nuts!
Each bright green and very spiky husk contains two or three nuts which start to fall from late September, though the nuts at this time will not be mature. The best nuts will be those that hang on only to be brought down by frost.
The sweet chestnut is not to be confused with another species, the horse chestnut (conker tree) Aesculus hippocastanum, which was introduced to Britain as late as 1616 and is from a completely different family more closely related to the lychee, but horse chestnuts are not considered edible. The conker was not always their most famous attribute. They were introduced, for their size and stature but mainly for their impressive flowers and have been used widely as avenue trees, a well renowned one being the mile long chestnut avenue at Bushy Park north of Hampton Court, which was designed by Sir Christopher Wren in 1699. People still meet every year on Chestnut Day (the nearest Sunday to 11th May) to celebrate them. You may notice that our horse chestnuts don’t look very well these days, with brown blotches on their leaves, this is due to a leaf mining moth whose caterpillars mine inside the leaves, this was first identified in Wimbledon in 2002 and spread across the country at a rate of 30km a year. Another lesser issue they have is leaf blotch fungus, neither of these are fatal but will reduce photosynthesis and so possibly weaken the trees own resources.
Interestingly, sweet chestnut is a cousin of both the beech tree Fagus sylvatica and the oak tree Quercus robar. Each of which have nuts of their own.
Looking at the nuts on the beech trees, I wonder if we might be having a beechmast year this year, where once every 5 years or so all of the beech trees drop a heavy crop of seed. The seeds being a desirable food source to animals such as mice and squirrels and young saplings being very attractive to deer, this is done so that through sheer number, some seeds and saplings may grow to maturity. If you can gather enough of these nuts and have the equipment to press them, then it is said that they make a very fine cooking oil.
Beech is recorded as a native tree to Britain, though I’m not sure how the people in the know about these things have slipped this through as it’s only a comparatively recent one, the pollen record showing it to have been present for approximately 3000 years.
The subject of whether a plant is native or non native is a tricky one but as a starting place the BSBI (Botanical Society of Britain and Ireland) would describe a native plant by definition as ‘either a plant that arrived naturally in Britain and Ireland since the end of the last glaciation (i.e. without the assistance of humans) or one that was already present (i.e. it persisted during the last Ice Age)’. The end of the last ice age was approximately 11,700 years ago.
Oaks also have mast years as acorns are of course nuts too and though technically edible are very bitter and high in tannin that requires leaching in order to make palatable. Perhaps the most well known use for acorns, apart from animal fodder, is coffee, something promoted during the war when supply chains for real coffee were limited, but once processed acorns can be roasted or ground into flour for a multitude of uses. I recently saw a recipe for acorn brittle that I’m interested to try!
NB, remember that it’s illegal to dig up any wild plant and always make double sure that the plant is what you think it is if you’re going to eat it.
Photo by Hugo Le Cam on Unsplash
