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were incomplete. Ali dynamic pressure gages were operable and records
were satisfactory. A peak static overpressure measurement taken in the
cleared av@- = BRL gage line on Uncle Island, which was at a ground
range about equal to the center of the tree stand, is given for comparison with measurements taken within the stand.
3.3

MAXIMUM DEFLECTION MEASUREMENTS

Shot 3 maximum deflection data from snubber trees on Uncle Island
were unsatisfactory due to breakage of instrumented trees or fouling of

wires by falling trees and branches. Deflections of instrumented trees
on Victor and William Islands were negligible although all snubbers
were operative.
As no usable deflection data were obtained the physical characteristics of snubber trees are not reported.

3.4

SHOT 1 DAMAGE

The William Island Pisonia stand near Station P-22 at a ground
range of 61,710 ft, 2.5 psi peak static overpressure, was heavily damaged. Before and after interior views of the stand are given in Fig.
3.1. Damage was primarily in the form of branch breaxage with some
uprocting and main stem breakage. Al. uprooted trees fell away from
ground zero. All broadleaf species were completely defoliated. Only
two defective palms were broken, others suffered only occasional loss
of fronds.
The Victor Island Pisonia stand near Station P-21, including the
sample pict, at a ground range of 67,500 ft, 2.4 psi peak overpressure,
were heavily c<omaged. Figure 2? 2 shows the plot interior before and
after Shot 1. i.jus % 7 g.-e5 an exterior postshot view cor comparison
with preshot view shown in Fig. 2.4. Damage was quite similar in appear~
ance to that on William Islard as the two smail islands were practically
contiguous. Tabie 3.2 presents number, size, and damage distribution

for the trees on the sample 1/4-acre plot.

There was 30 per cent branch breakage, considered as light damage,
in the Pisonia clump on the northwest end of Uncle Island near Station
P-13 at 75,400 ft ground range, 1.7 psi peak static overpressure, and
12 sec positive phase duration time. Damage also was primarily in the
form of branch breazage and heavy defoliation with occasional trunk
failure and uprooting cf smaller trees. Figure 3.4 shows the Uncle
Island Pisonia sample plot before and after Shot l.

3.5

SHOT 3 DAMAGE

Physical characteristics of trees on the four Unele Island sample
plots and corresponding breakage data are presented in Table 3.3. Fif-

teen of the 26 trees in the 4 plots or 58 per cent were damaged at an
average ground range of 8500 ft, 4.2 psi peak static overpressure.
This
degree cf damage is borne out by the appearance of the stand as a whole

and was considered heavy damage.

28

SECRET -— RESTRICTED DATA

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