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Introduction

This book was originally published in 1969 and has, for nearly 30 years, served as a guide to the natural history of the Oregon coastal dunes and to the plants found on them. In this edition we have updated the scientific names of the plant species to correspond with those in current use in local floras.

 

During these past thirty years changes have occurred in the dune landscape. The deflation plains, developing on the lee side of the foredune and between the lateral ridges of the large parabola dunes, were vegetated mostly by meadow species, with a few tree and shrub seedlings. Today impassable thickets of trees, coast pine (Pinus contorta) and Sitka spruce (Picea sitchensis) and shrubs western wax myrtle (Myrica californica), coast willow (Salix hookeriana) and evergreen huckleberry (Vaccinium ovatum) have grown up, requiring trails to be cut for access to the beach.

On the foredune and other areas of active, blowing sand, the continued spread of European beach-grass (Ammophila arenaria) has resulted in the suppression of the native dune-building and stand-stabilizing species. While not generally threatened with extinction, many of these species, such as the yellow abronia (Abronia latifolia), gray beach pea (Lathyrus littoralis), beach morning-glory (Calystegia soldanella), American dune-grass (Elumus mollis)and large-headed sedge (Carex macrocephala) are no longer seen in the abundance of thirty years ago. One endangered species pink sandverbena (Abronia umbellata ssp. breviflora) which was once abundant along the coast from British Columbia to northern California is now restricted to a few sites from the central Oregon coast south. Since 1991 efforts have been underway by the Plant Conservation Biology Program of the Oregon Department of Agriculture to reintroduce this species to create new populations. Reintroduction has been most successful in sites where European Beach-grass has been brought under control.

Control of European beach-grass has been undertaken, with some success, in certain areas to improve the habitat for an endangered bird, the snowy plover (Charadrius alexandrinus ssp. nivosus). In addition, biological control agents (primarily seed weevils and the Gorse Spider mite) have been introduced by the Oregon Department of Agriculture in cooperation with other agencies and private land owners to help control the spread of gorse (Ulex europaea) and Scotch broom (Cytisus scoparius)

The main purpose of this book is to help visitors to the sand dunes, regardless of their background, to become a little more familiar with the landscape they see, and with the forces of nature operating within that landscape. A great deal of satisfaction can be obtained through knowing something of the story behind the things one sees in nature: the effect of climate, why plants grow where they do, the names of the plants, etc.

The sand dunes of the Oregon coast offer some of the most spectacular seashore landscapes to be found anywhere in the country. Readily accessible by highway, they have become a source of interest to increasing numbers of travelers to the Northwest. Oregon's excellent State Park system and the establishment of the Oregon Dunes National Recreation Area (ODNRA) also draw large numbers of visitors to the dunes areas.

The first chapter of this book deals with the sand dune area as a whole--its geologic history, climate, dune forms and formation of dunes, and some general observations on the vegetation. Much of this information was put together from many sources, and numbers in parentheses throughout the text refer to a bibliography which lists the major sources of information.

The next four chapters discuss the plants and plant communities of the sand dunes. The information is based largely on the dune areas from Tillamook Head to Coos Bay. Many plants of the Clatsop area dune ridges are included, but this area has many additional species that have been introduced by the activities of man. Likewise, the coast below Coos Bay has a slightly different climate from that of the rest of the Oregon coast, and consequently there are many additional plant species present.

The plants included in this book are only those that might be considered common on the dunes. It does not include at least as many more that are less common. It does not include roadside plants of the "non-dune" coastal forest, except when these occur on the dunes.

Common names are used in the discussion with the scientific name given in parentheses the first time it is used in a chapter. Whenever possible, it is desirable to learn the scientific names of plants, since common names can be a source of much confusion.

The taxonomic key of Chapter 6 includes ninety of the plants one is most likely to see on the sand dunes. Instructions for its use precede the actual key. In addition to the plants in the key, forty other species are described in the description section. Identifying characteristics are based on flowers and leaves, which would make it most useful during the spring and summer months. However, the key, together with the photographs and descriptions of the plants in Chapter 7, should make it possible to identify many of these species throughout the year. Mosses and lichens are not included in the key. A glossary is included that gives definitions of commonly used botanical terms.

A number of individuals assisted in the preparation of this work; namely, Kenton L. Chambers, William W. Chilcote, Ronald J. Tyrl, the late Weldon K. Johnston, Richard R. Halse and Thomas N. Kaye. We wish to thank them for their valuable assistance.

The photographs were taken by the late Frank H. Smith, with the exception of Ceanothus thyrsiflorus (blue blossom), which was kindly furnished to us by Mr. and Mrs. Orin Hess of Wedderburn, Oregon.

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