But wherever the soil has been enriched by the decomposition of the leaves of the birch the battle begins.

The birch still flourishes on the borders of lakes and other marshy places, where its enemy cannot exist.

In the same way, in the forests of Zeeland, the fir forests are disappearing before the beech.

Left to themselves, the firs are soon displaced by the beech.

The struggle between the latter and the oak is longer and more stubborn, for the branches and foliage of the oak are thicker, and offer much resistance to the passage of light.
The oak, also, has greater longevity; but, sooner or later, it too succumbs, because it cannot develop in the shadow of the beech.