Sound palm trees cf various heights were selected across Uncle Island stand, and were provided with a snubber wire arrangement to measure maximum deflection of the center of pressure of the tree crowns under shock loading. Similar snubber wires were installed on palm trees on Victor and William Islands. Snubber wire arrangement consisted of two lengths of piano wire attached to the tree at the center of pressure of the tree crown end led down through friction grips on stakes driven into the ground, each a different mown distance from the base of the tree on a radius toward ground zero. Sufficient tail was provided each, and measurements pre- and post-Shot 1 permitted calculations of the maximum movement of centers of pressure under shock loading. 2.4 SAMPLE PLOTS To assess damage in detail to tree stands from shock-wave winds accompanying Shot 3 in terms of stem and branch breakage and defoliation, and to demonstrate how damage to individual trees is influenced by their location in the stand, sample plots were established on Uncle and Victor Islands. Plots were photographed and tree characteristics were measured prior to Shot l. On Uncle Island one Pisonia and three palm sample plots were selected along a radius spanning the center of the island. Sample plots for tree measurement were about 1/5-acre in area and contained from six to eight large trees with an understory of brush. Sample plot tree data are presented in Table 3.3. Figure 3.4 gives the pre-Shot 1 appearance of the Uncle Island Pisonia sample plct looking away from ground zerc. Only one sample plot was studied in the pure Pisonia stand on Victor Island as the island was considered too nerrow to detect differences in individual tree breakage with position in the stand. A 100 per cent cruise of the trees on this 1/4-acre plot was made recording dian- eters and heights. These data are given in Table 3.2. A ground photo- graph of the sample plot taken prior to Shot 1 is presented in Fig. 3.2. 2.5 2.9.1 STATIC BREAXAGE TESTS Field Tests Prior to Shot 1 static bending tests similar to those conducted for ponderosa pine?/ were applied to 10 naturally rooted coconut palms in the Uncle Island stand to determine the force and deflection necessery for breakage. Static deflection measurements were necessary for calculating predicted deflection for breakage, Table 2.2 gives physical characteristics and static breakage data for all test specimens. Palms on the three test islands were dered cne population for application cf bending strength test data. 2.5.2 Standard Test: a strensth parameters for green paim and Pisoria Sly, arranzements were made fcr + Service, - ~ + Div. of Fire Research, SECRET- RESTRICTED DATA