ORE-75217 
Figure 10.—Gorse, a leguminous shrub adapted to coastal dune areas, should 
not be used because it is a noxious weed and an extreme fire hazard. 
Gorse, a leguminous shrub widely naturalized to coastal conditions 
(fig. 10), meets some of the requirements but has several undesirable 
characteristics and should never be used. Its highly flammable 
volatile oils make it a fire hazard. It sprouts readily from the 
crown when mowed or burned. Gorse is intolerant of shade, but trees 
for permanent stabilization are hard to establish in stands of this 
shrub. 
Trees for Stabilization 
A total of 150 accessions of 80 species of trees were tested for ad- 
aptation to stabilization of dunes of the north Pacific coast. They 
represent most of the species recommended in the literature on dune 
control. Observations and some measurements were made for 10 years 
and some were continued for more than 20 years. The adapted species 
can be classified into two use groups. 
Trees for semipermaneni stabilization 
The species in this group are easy to propagate, establish quickly, and 
grow rapidly on immature sites on which the sand has been stilled. 
The adapted species are native subclimax trees that are gradually 
replaced by climax species as the sites mature. 
Shore pine (fig. 11) is ideally suited for semipermanent stabili- 
zation on moderate and well-drained sites on the dunes. It is easy 
to establish in intermediate plantings of shrubs. The rate of growth 
is phenomenal, averaging 2 feet per year. When used for topograph- 
ical correction it quickly becomes wind formed® and maintains this 
* Wind forming is described by Braun-Blanquet et al. (1932). Continuity 
of wind action is the climatic factor that affects the form of vegetation. 
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