It may seem a little weird, when summer seems at last to be arriving, to be considering bark. On the other hand, in my wanderings on the Italian peninsula recently, I found myself photographing as much bark as I did leaves and flowers; and I took advantage of my period of restricted mobility to do virtuous thinks like putting all my bark pictures into one folder.
The truism is to say that the bark is the skin of the tree: yes, to the extent that it is the outer protective surface of the organism. But it is hugely tougher than skin: it is rare that a plant ‘bleeds’ to death from a single wound, and these usually heal readily. Think of the harvest of maple syrup, or rubber, or (most spectacularly) cork, all of which depend on damaging the bark of the tree and relying on it to regrow and heal quickly.

Harvesting cork oak in Spain.
(How kind of Evolution/the Creator to have the foresight to evolve a tree that could be used to stopper the drinkable products of other plants.)
There is an interesting table here of the various sorts of damage done to tree bark in the UK by different animals, from red deer to edible dormice, via the more familiar rabbits and grey squirrels. We must be thankful that we do not have native porcupines, as this is what they get up to.

Porcupines attack! Note the worryingly long tooth marks. (Credit: Adair Tree Care Ltd.)
There are of course scientific explanations for the enormously varied appearance of the bark of different tree species – whether protection from weather extremes, animal attack or disease prevention. Can ornamental trees can be bred for bark? Or are the various cultivars of e.g. Betula utilis jacquemontii (Snow Queen, Graywood Ghost, etc.) clones rather than grown from seed?

Victor Jacquemont (1801–32), French explorer and botanist. The birch is the most famous plant named for his, but there are also an Acacia, a Corylus, an Arisaema and a Prunus jacquemontii.
Anyway, here are just a few of the remarkable barks I’ve seen recently, out of an endless variety of forms!
Caroline

Broussonetia papyrifera (the paper mulberry tree) in the Botanic Garden in Florence.

A horse chestnut (Aesculus hippocastrum) in a Cambridge street. New shoots appear from the scar tissue of lopped branches every spring.

Quercus suber (the cork oak) in Florence.

Quercus robur (the European oak) in Lucca.

Crataegus mollis (downy hawthorn), with added lichen, in Lucca.

A silver birch at Angelsey Abbey, Cambridgeshire.

Parrotia persica (the Persian ironwood) in Cambridge University Botanic Garden.

Pterocarya fraxinifolia (the Caucasian wingnut), with ivy on its shady side, in Lucca.

Lagerstroemia indica (the crape myrtle), in the Botanic Garden at Modena.

Platanus x acerifolia (the London plane) in Florence.

From its fruit, this massive tree in Cambridge ought to be a London plane, but the bark is quite different – a sign of age?
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