SECRET ° Previous page was blank, therefore nov t1inec. CHAPTER 1 INTRODUCTION 1.1 OBJECTIVE Project 2.3, Operation CASTLE, was part of a research program sponsored by the Armed Forces Spec!ai Weapons Project (AFSWP) aimed a+ prediction of blast damage to forested areas from atomic explosions. A knowledge of blast damage to forested areas provides a means of assessing the degree of damage to material and personnel and/or the amount of cover the forest affords. Degree of blowdown to the forest stand will also impede troop movements through or out of the area. The objectives of this project were: 1. To determine blast damage to trees in terms of stem breakage, branch breakage, and defoliation where effects are influenced by their location in a naturel tree stand. 2. To determine the effect of natural forest cover on the shock wave in terms of its peak static overpressure and peak dynamic pressure attenuation. 3. To provide individual tree breakage data in the region of long positive phase duration times in order to substantiate the basis for breakage predictions. The degree of momentum exchange between the shock wave and obstacles, such es trees in a stand, capable of absorbing substantial amounts of energy is not well known. There is no immediate theoretical or scaled model method of analyzing the interaction of shock wave and trees in a neturai tree stand; therefore it was necessary to achieve stated cbjectives experimentelly. CASTLE presented an opportunity to make measurements on a natural stand several times larger than the Operation UPSHCT-KNOTHOLES/ experimental stand. Even though the natural stand was composed of tropicel trees, breakage data were desirable since continental tests in forested areas are not imminent. i AFSwr, UPSHCT-KNOTHOLE, Project 3.19, Blast Damaze to Coniferous Tree Stands by Atouic Explosions, WT-731, January 1954. NAS . + nestricied Data. aw) errpr SECRET RESTRICTED DATA CONFIDENTIAL--