The Forests and Wildflowers
Our continent has a variety of climates, and each climatic area has its appropriate vegetation. Generally, the interiors of continents do not have forests, but have grass or desert vegetation. The most luxuriant forests develop near oceans where climate is sufficiently moist. This is true of other continents as well as North America.
The differences in the general character of our natural vegetation from coast to coast and border to border are apparent despite three centuries of man’s disturbance in the East and one century in the West. Sizeable samples of some of the many kinds of original vegetation are preserved in national parks and monuments. These are precious remnants of our plant heritage that become more valued year by year in proportion to their scarcity elsewhere.
The mild, humid climate of the northern half of the Pacific slope is unusually favorable for forest growth. The most luxuriant of the western forests developed here in unbroken stretches. The forests that girdle the Olympic Peninsula represent the best development of this evergreen forest domain. Its ultimate composition is of western hemlock and western redcedar in dense stands, with trunks commonly 4 to 6 feet in diameter and 125 to 200 feet tall. Their crowns shut out most of the sunlight, but enough gets through to the bottom of the forest for the growth of mosses and ferns. Shrubs grow dense and tall, in places becoming almost impenetrable to hikers. Fallen trees of all sizes soon are enveloped by the lush growth in the damp shade, and in time return to the soil through decay.
Hemlock and redcedar seedlings take root in the forest litter or on prostrate, moss-covered trunks. They are able to live in the deep shade. The most hardy of them outstrip their rivals, and when a vacancy occurs in the forest canopy their growth speeds up. Thus a forest of hemlock and redcedar is maintained. This is the climax forest in the lowlands of the northwest coast. It is the kind of forest the climate here will produce and maintain in the absence of interference.
Interference has been the rule, however, both before and since the coming of man. Therefore, the climax forest is less common than the subclimax in which Douglas-fir is the dominant tree. Forest fires have repeatedly exposed the forest floor to sunlight and thus allowed the development of Douglas-fir, by far the most abundant and widespread tree in northwest forests. In the regeneration of a forest after fire, logging, or other disturbance, it is Douglas-fir that is ever present.
The northwest coast is an evergreen land. This may not be apparent in summer, however, when all plants are green. Not counting the numerous mosses that are always green, there are 73 species of evergreen plants on the Olympic Peninsula.
DRAPERIES OF CLUBMOSS HANG FROM LIMBS IN THE RAIN FOREST.