Geoscience Reference
In-Depth Information
120
35
(A)
(B)
PONDEROSA PINE FOREST
OAK GROVE
30
25
100
In leaf
80
20
60
Bare
15
40
10
5
0
20
0
01234
56 7
01
234
Wind speed (m s
-1
)
Figure 12.12
Influence on wind velocity profiles exercised by: (A) a dense stand of 20m high ponderosa
pines (Pinus ponderosa) in the Shasta Experimental Forest, California. The dashed lines indicate the
corresponding wind profiles over open country for general wind speeds of about 2.3, 4.6 and 7.0m s
-1
,
respectively; (B) a grove of 25m high oak trees, both bare and in leaf.
Sources: A: After Fons; and Kittredge (1948). B: After R. Geiger and H. Amann, and Geiger (1965). By permission of Rowman
and Littlefield.
Distance (meters)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600 1700
100
(A)
80
60
WIND
40
20
0
10
0
10
20
30
40
50
0
500
1000
1500
(B)
Vertical exaggeration x8
10
WIND
5
0
15
10
5
0
5
10
15 20 25
Multiples of shelter belt height
30
35
40
45
50
55
Figure 12.13
The influence of shelter belts on wind velocity distributions (expressed as percentages of
the velocity in the open). A: The effects of one shelter belt of three different densities, and of two back-
coupled medium-dense shelter belts. B: The detailed effects of one half-solid shelter belt.
Sources: A: After W. Nägeli; and Geiger (1965). B: After Bates and Stoeckeler; and Kittredge (1948).
