A premise in bonsai is that the best bonsai look like old trees. In my opinion a lot of ‘best’ bonsai look more like fantasy trees from a Studio Ghibli film, and not at all like real trees. I live near Richmond Park in London which has 1300 veteran trees, of which 320 are considered ‘ancient’ (in the third and final stages of their lives)ref and I know that they have reverse taper, weird branching, knots, breaks and all sorts of attributes which bonsai rules would aim to avoid. So what do we know about old trees and how they actually look?
The Woodland Trust Ancient Tree Inventoryref identifies the following general characteristics for ancient trees:
- Crown that is reduced in size and height
- Large girth in comparison to other trees of the same species
- Hollow trunk which may have one or more openings to the outside
- Stag-headed appearance (dead branches in the crown)
- Fruit bodies of heart-rot fungi growing on the trunk
- Cavities on trunk and branches, running sap or pools of water forming in hollows
- Rougher or more creviced bark
- An ‘old’ look with lots of character
- Aerial roots growing down into the decaying trunk
For species-specific attributes check out the Ancient Tree Inventory websiteref which outlines specific attributes for eleven of the most common UK species (Oak, Ash, Beech, Yew, Sweet Chestnut, Alder, Hornbeam, Scot’s Pine, Hawthorn, Field Maple & Lime).
Another studyref outlines some of the expected characteristics of ancient and veteran trees as “a hollowing trunk, holes and cavities, deadwood in the canopy, bark loss and the presence of fungi, invertebrates and other saproxylic organisms.” And citizen submitted recordings of tree measurements across the UK in the same study showed that “ancient trees have larger girths in general than veterans, which in turn are larger than notable trees.”
Trouet in her book Tree Story says that in old trees the top of the tree has ‘caught up’ with the bottom, so the trunk becomes more columnar, whereas a middle-aged tree is more tapered. She also says that branches thicken. This perhaps goes against the bonsai edict of taper above all else.
Another study reports that mature trees have only short shoots – these have smaller leaves and more foliage per shoot that more immature long shoots. Read more in shoots.
So to create a bonsai which looks old, you want it to have a very wide, columnar but hollowing trunk, rough or deeply grooved bark, holes, cavities, dead & broken branches, a compact canopy with deadwood, small leaves on short shoots, and ideally some fungi and a busy community of invertebrates.