The history of a forest is written in the shape of its trees. The shape of each tree tells not only its life story, but also the story of its neighbors: where they lived, who came and went, when they departed.
Woodland trees have a distinctive shape: deep wide crown, short fat trunk, and thick low branches. They’re great for wildlife and beautiful to behold. So how do you grow a woodland tree? Like good Slow Food, the recipe is simple but can’t be rushed. The key ingredients are space and time: space to spread and time to sag. Without both, a woodland forms a forest.
Step 1 – Provide lots of space to spread
When a young sapling is surrounded by lots of neighbors, most light comes from straight above. Light from the sides is intercepted (and used) by neighboring trees. As a result, closely-spaced trees grow straight up towards the light, not sideways. To do this, they shed the shaded, lower branches and leaves. This leaves a long, bare trunk, and a small upper crown.
By contrast, a sapling with no neighbors receives light from the sides as well as from above. Branches low on the trunk are retained, not shed, as they capture light from the sides of the tree. This creates a wide canopy, with low branches, a short trunk, and a deep canopy with low-hanging foliage.
A picture-book woodland tree wouldn’t be a picture-book woodland tree if it didn’t have a short trunk and thick low branches. To grow these features, it needs space to spread sideways.
Step 2 – Add lots of time to sag
Space alone doesn’t create a majestic old tree. It also needs a liberal dollop of time; time to grow and time to sag. As branches grow older, they get thicker and heavier. It’s hard to hold up all that weight, so just like us, old trees sag. New branches stretch up to the sun while the old boughs bend to the ground.
The bent boughs of an old tree didn’t always bow down low. They started off perky and erect; time did the rest. Look at the upper branches of a young tree. They don’t sag. They head bold upright, and the angle between each branch and the central trunk is narrow (acute). As the tree grows, each branch is over-topped by younger shoots. As you scan a tree from top to bottom, the angle between the trunk and each branch widens. The top branches head upwards while the lower branches head outwards. Every low branch was once at the top of the tree, and they all started off upright, stretching towards the sun.
As a tree grows older still, big old branches bend in the middle and bow down to the ground, weighed down by accumulating wood. Compare a young tree, growing out on its own, against an old veteran tree. The lower limbs of the young tree might spread wide, but they rarely sag down towards the ground; gravity and age does that. For an aging tree, “every asset’s heading south,” as Tim Rogers once sang.
Step 3: Add time again to grow new branches
There’s another reason why old woodland trees look like they do. An old tree is like an old house that’s been added to regularly. Some bits are old and others are new. As time goes on, old boughs sprout new young shoots, not just from the end, but along the length of the branches.
The lower boughs of a mature, actively growing tree are often clean, with few side branches. Why don’t new branches grow along these open boughs? Trees and shrubs don’t want to invest energy to grow leaves in positions that won’t receive much sun. So the foliage at the end of each branch produces hormones that inhibit buds further back along the stem. When the terminal foliage is growing actively, the buds along the branch stay suppressed, and no new side branches can grow.
When old branches die and break, less inhibitory hormones are produced. This lets the buds (that were once suppressed) along the remaining bough spring into life, and new secondary branches grow along the once-bare bough. This second wave of regrowth often creates erect, upright branches on the upper side of the older boughs.
The big upright branches in the center of the tree above didn’t exist when the tree was younger. Instead they formed when the bough they grow on began to die. It takes a long time for a bough to grow wide, to die back, and for another big bough to grow upon it.
As time progresses, these secondary branches may bear another crop of younger branches, when they in turn start to die back. Like a renovated old house, an old tree accumulates successive generations of branches; boughs on boughs, trees in trees.
Step 4: Stand back and admire the handiwork
To grow a picture-book woodland tree – with a deep wide crown, short fat trunk, and thick low branches – you need space, time, and more time again. Like good Slow Food, the recipe is simple but can’t be rushed. You just can’t skimp on space nor time.
- The candles of Dunkeld
- Forgotten woodlands, future landscapes
- Dense old trees: bitter & twisted ‘charismatic megaflora’