At the corner of Route 73 and 9N, overlooking a snowcapped ridge of Adirondack peaks, a 60-foot tall elm tree stands sentinel at the edge of a wetland valley. A popular stop for photographers and tourists, its sweeping branches provide a foreground to the mountains. This elm tree has also captured the attention of scientists. Only a few yards away, a grove of elms has fallen victim to Dutch Elm Disease. On Monday scientists from the Nature Conservancy took samples of the healthy tree.