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forest-tundra ecotone did provide a preliminary in- dication that the original justification was sound (Andrews, this vol. p. 87). This has also been corroborated independently by Maher (1961) and by Petersen and Mehringer (1976). While some progress has been made, it would seem that we have done little more than more nearly define the problem. THE GEOGRAPHIC FRAMEWORK Since the detailed process studies were to be con- fined to two small alpine catchments and three modest tracts of forest, the need to develop a feel for the entire San Juan Mountain area was imperative. This need expressed itself in an ecological overview subproject which, with the progress of the SJEP, de- veloped three major emphases: 1) mapping the vegetation from conventional air photographs and satellite imagery (LANDSAT and Sky lab supported by fieldwork); 2) mapping the geomorphology, again using remote sensing and field techniques; and 3) collecting a large group of black and white photo- graphs to provide a permanent graphic record of the San Juan Mountain ecosystems at the time of cloud seeding initiation. Justification of these sub- projects can be made simply because of the need to know as much as possible about the landscapes of the San Juan Mountains so as to provide overview per- spective for assessment of the relevance of the de- tailed process studies. A further original objec- tive had been the hope that 1:24,000 scale maps of the cover types of the San Juan Mountains would facilitate extrapolation of results from the detailed process studies ,to the entire area. The vegetation mapping was completed for 63 1:24,000 scale maps sheets through cooperative effort with two NASA- funded projects (contract numbers NAS5-21880 and NAS9-13380). Eleven geomorphological maps at a similar scale were completed. Finally, the ground photograph collection lies mainly in negative format because of the lack of funds for printing, annota- ting, and cataloguing. While these subprojects have provided a large amount of valuable descriptive data on the San Juan Moun- tain environments they were not utilized by the process studies to their potential limits because of the problem of timing, and to a lesser extent, of funding level. The contractual constraints made it impossible to move in an ideal manner whereby the overview subprojects would be completed first and then used as a basis for selection of detailed study sites for the process-oriented subprojects. This does not necessarily invalidate our recognitior that under ideal circumstances 'the proj ect design would be different. Also, the overview data should certainly provide a vital basis for assessment of long-term ecological impacts should operational cloud seeding be initiated in this area. COLLABORATION WITH OTHER RESEARCH PROJECTS The scale of cover-type mapping indicated above would not have been possible without our ability to coordinate the objectives of the two NASA remote- sensing projects which were undertaken jointly by INSTAAR and the Laboratory for Application of Remote Sensing, Purdue University. All INSTAAR research efforts benefitted greatly from our being able to match the objectives of a group of National Science Foundation-supported mountain training projects. Each summer we were able to add to the San Juan field teams high ability high school students, undergraduates, and junior college teachers. Finally, the presence of a year-round office in Silverton as headquarters of the INSTAAR avalanche research team, proved an enormous logisti- cal asset. The silver studies benefitted from separate support from the Weather Modification Pro- gram, Research Application Directorate, National Science Foundation, under grant AEN 73-07821-AOE. LITERATURE CITED Bradley, R. S. 1976. Precipitation History of the Rocky Mountain States. Westview Press. Boulder, Colorado. 356 pp. Bradley, R. S. 1976b. Seasonal precipitation fluctuations in the western United States during the late 19th century. Monthly Weather Review (in press). Maher, L. J., Jr. 1961. Pollen analyses and post- glacial vegetation history in the Animas Valley, unpublished Ph.D. Thesis, University of Minn. Petersen, K. L. and Mehringer, P. J., Jr. 1976. Postglacial timberline fluctuations, La Plata Mountains, Southwestern Colorado. Arctic and Alpine Research (in press). 1 'I (j 1 42