Developmental history of European beachgrass (Ammophila arenaria (L.) Link) plantings on the Oregon coastal sand dunes

Graduation date: 1965A study of Ammophila, a,renaria (L. ) Link, (European beachgrass) plantations was carried out on sand dunes along the Oregon coast to observe the vegetation changes which occur over a period of years. Control of moving sand has been important on a world-wide basis for many years. In Oregon this problem has been the cause of concern since the 1930's. Ammophila is well adapted to the extreme environment of a coastal area and t is most vigorous in areas of drifting sand. It is a coarse, perennial grass used extensively in planting of sand dunes for stabilization. Ammop1i1a is the primary\ud species used in the Oregon plantation work.\ud Transplanting of the grass clones is the moat frequently used method of planting on the dunes. Clones are planted with varying\ud density and number of culms per hill according to the direction and degree of the slope. The planting is carried out between November and April when weather is cool and wet. To insure permanent stabilization, secondary woody species are planted in the established Ammophila. The species used are Cytisus scoparius (Scotchbroom) and Pinus contorta (Lodgepole or shorepine). Cytius is planted before or concurrently with the Pinus to provide protection for the Pinus.\ud Thirteen consecutive years of plantations were located and studied south of Florence, Oregon, where planting has been in progress\ud since 1949. A 25 foot square plot was located in a uniform and typical area within the plantation. The plot was divided into five foot square quadrats with three foot square quadrats placed within each of these. Data included height, cover, diameter of clumps and density of Ammophila; height, cover and density of Pinus and Cytisus; cover of litter and Mnium sp. (moss); and frequency of the native species present in the plots. An analysis of sand determined the pH, total nitrogen and organic matter present. The plantations varied in overall appearance for the 13 years. Ammophila showed a definite change from the clumped growth form observed in the first years of growth after planting to solitary shoots\ud present in the oldest plots observed. Pinus and Cytisus showed a varied appearance throughout the plots with a general increase in height and cover. Density varied with the degree of success of the plantings. Native species were present and the frequencies varied with plantation age and location. The soil analysis proved a definite decrease in pH with age of the plantation. The oldest plot observed showed numerous native species including. Picea sitchensis (Sitka Spruce). In time the areas now being planted will develop a typical native vegetation without any of the original planted species present