TREES FOR WATER CATCHMENT AREAS 149 
flowering plants, like Anemone, Oxalis, Circaea, and Asperula, 
with woodland grasses, like Miliwm and Melica, and with 
oak fern. The beech then grows vigorously, developing 
tall stems (Fig. 27), and regenerates freely. 
Beech is tender to frost when young; and seedlings may 
often be raised with advantage under the protection of light- 
foliaged trees, like birch, ash, or oak. It should not be 
planted in low-lying frosty situations, unless under the cover 
of an advance growth of birch. It will grow up to a con- 
siderable altitude in the mountains, but becomes stunted in 
height and ceases to produce timber in quantity. It is 
accordingly not of much value as a main-crop tree in planta- 
tions in the hill pasture zone. Below this zone, beech 
should be grown pure on poor calcareous soil, on which no 
other tree will thrive. On other soils, as explained above, 
it should be grown largely to form a matrix for valuable 
timber trees, like ash, oak, elm, sycamore, and larch. Most 
of these trees may be scattered amidst the beech, singly or 
in very small groups; but oak is better planted amidst 
beech in large groups. 
Ash.—The common ash is perhaps our most valuable 
broad-leaved tree. It produces a strong, tough, elastic, light 
wood, which is essential to our industries, and cannot be 
replaced by any imported substitute. It grows fast, and 
is ready for felling at an early age, the timber being always 
saleable at a good price. For these reasons, ash ought to be 
more extensively cultivated; but there are difficulties in 
the successful planting of this species which can only be 
overcome by a thorough understanding of its peculiar re- 
quirements. It can rarely be grown in a wood by itself. 
Pure plantations of ash on a considerable scale are often 
attempted, but do not seem ever to be successful. Once it 
has passed the young stage, ash requires much light and 
space. Under the scanty cover of its sparse foliage, the soil 
deteriorates, losing its moisture and often becoming clothed 
with dense grass, which seriously checks the growth of the 
trees in height and diameter. Ash scarcely flourishes unless 
