A friend of mine who recently visited Japan pulled out her phone to show me pictures of Kyoto’s famous bamboo forests. She described her awe at the tall green trunks and the peaceful sound of their rustling leaves,
I had to tell her that bamboo is not a tree. In fact, bamboo belongs to the same plant family as the grass in her lawn.
To a botanist, a tree is not defined by height, but rather, by the way it grows.
A true tree grows in two dimensions. First, it gets taller by extending from the buds at the tips of branches. Second, it grows wider through the cambium, the layer of tissue just under the bark that that adds new wood each year and creates annual growth rings.
But bamboo grows only in the first way. A bamboo shoot — called a culm — emerges from the ground with its final diameter already formed. The shoot then rapidly elongates, like a telescope stretching upward, until it reaches its final height.
Once fully grown, it doesn’t get wider or make annual growth rings. So, what looks like a trunk is actually a giant stem of grass.
Nature doesn't always fit neatly into the categories we see with our eyes. Although bamboo forests can feel every bit as majestic as forests of cedar or pine, they are actually the giant cousins of the grass in your front yard.
Sometimes the wonder of trees comes from discovering what is — and isn't — a tree at all.
