I really love root plates. They’re the disc of earth, stones, and roots that you often see when a big tree falls over. They reveal something otherwise hidden: a snapshot of what was going on a bit underground, directly under the trunk itself. The most surprising thing is just how shallow they are. Twenty metres of substantial tree trunk laid on the ground but only a foot or two of substantial roots.
Root plates naturally have a mention in Oliver Rackham’s magisterial “Woodlands”:
“until 1987 few English people understood what a tree’s root system looked like; some thought roots went as nearly as far below ground as stems above it. As the great storms of 1987 and 1990 showed, most trees in England are shallow rooted. It may be argued that deep-rooted trees were never uprooted, but anyone digging holes in a wood seldom meet roots more than 3 feet (1 metre) down. A giant beech can have a root-plate only a few inched deep, much less than the diameter of the trunk.”
This month I took pictures of pine and birch root plates in the woods above Carbeth and in the Black Wood of Rannoch in Scotland.
First these pictures from a stand of trees near the top of the Carbeth hutting site. You can see a double root plate with two trunks and then a single root plate. The third picture shows how shallow the root plates are, and the final picture puts them in context: right on the edge of the wood by an area of marshy ground before the huts start.
These next four are from the Black Wood of Rannoch just to the south of the Cairngorms national park. I’m writing a separate blog post about the wood, as it’s an important survival from the ancient Caledonian forest, but for now, let’s just look at some birch root plates. It striking how similar they look despite pine and birch being completely different species.
Finally, another pine root plate, taken in the rain in Grizedale Forest in the Lake District national park:
Root plates are formed when trees are unstable and fall over. A storm can help this, especially one in summer when deciduous trees are in full leaf. Rackham explains that trees have a lot more roots than they need to draw water and nutrients, and the excess is there for stability. Trees that can grow fewer roots than they want are more at risk. So being up against a river bank, or a road, or other trees doesn’t help. Paradoxically, it is more often the trees inside a wood than on the edges that get blown over by the wind, especially if the wood has been planted with an artificially high density.
There are lots of videos of trees falling and root plates forming on YouTube. This compilation is “Trees falling in nature”, although mostly they’re in gardens or struggling to balance in the grass verge beside a pavement: