A massive oak claims its ground for 200 years or more, outcompeting all other would-be canopy trees by casting a dense shade and drawing up any free water in the soil.
For instance, without a tree to absorb radiation from the Sun, to offer shade, the full intensity of that radiation reaches the ground.
例如，如果没有树木来吸收太阳的辐射并提供树荫，那么太阳辐射就会完整地到达地面。
3
The shade at ground level is perfect for rare Asian nettles; on the brighter upper stories, plants that usually cling to windblown cliff faces brave the blustery British breezes.