of extensive areas of eroding dunes on the north Pacific coast. They 
pointed out that trees and shrubs were essential to erosion control on 
some sites, while on others the choice between herbaceous and woody 
perennials for permanent stabilization depended on the use of the 
area. The land capability and the economic and social considerations 
determine the use of the stabilized area. 
Most of the dune areas on the Pacific coast of North America are 
in land-capability classes VII and VIII.*? Such lands have severe 
limitation for use because of the erosion hazard, low fertility, or low 
water-supply capacity. Small areas of class VI land with shghtly 
less erosion hazard and of excessively wet class V land are interspersed 
with the class VII and VIII land of the dunes. Small areas of class 
III and IV land occur on some coastal dunes. These may be used 
for cultivated crops or pasture, but they require large amounts of 
fertilizer and supplemental irrigation. If cultivated crops are grown, 
extreme precautions must be taken to prevent wind erosion. 
The same conditions that preclude the use of stabilized dunes for 
cultivated crops or pasture also limit their use for the production of 
major forest products such as lumber, poles, or pulpwood. Minor 
forest products such as Christmas trees, charcoal, and florist greenery 
are possible with intensive culture when areas are near markets. 
The use of coastal dunes for recreation is consistent with both 
their land capability and their location. Large centers of population 
are usually located near the coast, and improved highways make them 
readily accessible to vacationers. Recreational use of coastal dune 
areas is enhanced by the proper use of trees and shrubs for permanent 
stabilization (fig. 1). Precautions must be taken to preserve the 
permanent cover from damages by overuse, careless use, and fire. 
Major Uses of Woody Plants in Dune Stabilization 
Woody plants have both direct and indirect conservation value 
when used for dune stabilization. Trees with an understory of shrubs 
can provide permanent stabilization. They are also used for topo- 
graphical correction, for protection of areas against indiscriminate 
use, and for windbreaks. The permanent shrub understory provides 
ground cover, food and cover for wildlife, and food for human use. 
The permanent cover of woody plants on coastal dunes is never 
established directly on eroding sites. Subclimax shrubs and trees 
prepare such sites for the permanent cover. The subclimax species 
are planted as an intermediate step between initial plantings of sand- 
stilling grasses and the permanent cover. Therefore, care is required 
when designing the steps needed for initial, intermediate, and perma- 
nent stabilization. 
*The land-capability classification is an interpretive grouping of soils for 
agricultural purposes in which all soils are placed into eight broad classes. 
Soils having a large number of alternative uses are placed in land-capability 
class I and those with few are placed in class VIII, and considering all uses 
collectively the risks of soil damage or limitations in use become progressively 
greater from class I to class VIII. In this classification the individual units 
shown on a soil map are first grouped into capability units. The soils in one 
capability unit need similar management and have the same general suitability 
for use. Thus they are a basic management unit for common farm crops. 
Capability subclasses show the kind of management problem—risk of erosion, 
wetness or overflow, soil or rooting-zone limitation, or climatie limitation 
(Klingebiel and Montgomery, 1961). 
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