One of the reasons why birch managed to colonise the newly emerging lands following the retreat of the glaciers lies in its abundantly-produced seed, as fine as powder. Even today, it remains what botanists call a ‘pioneer’ species, one of the first trees to occupy suitable ground. That said, it is not a long-lived tree; most specimens die or succumb to fungal attack by the age of 70. However, they do offer protection to slower-growing, longer-lived tree species such as oaks, and where left to regenerate birches can play an important role in helping to nurture a wood.
The catkins appear early in spring and release their pollen in clouds during April. The leaves emerge shortly after, a bright emerald green at first and finally turning golden in autumn.
Birches produce an abundance of sap in spring and a cut stump will continue to ‘bleed’ for weeks. In North America, a species of woodpecker called the sapsucker taps birch trees in spring by cutting small wells in the bark and drinking the sap which oozes out. In the UK, a similar technique is employed by makers of birch tree wine, a drink once believed to have medicinal properties, including those of curing kidney stones and skin complaints.