THE NATIONAL ACADEMIES PRESS
500 Fifth Street, N.W. Washington, DC 20001
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this study was provided by the U.S. Department of the Interior under cooperative agreement number 1443CA5280-9-0929. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number 0-309-008728-7
Additional copies of this report are available from the
National Academies Press
, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624–6242 or (202) 334– 3313 (in the Washington metropolitan area); Internet, http://www.nap.edu
Cover: Can Do Restoration. Photograph by Clyde Butcher. Copyright © 1996 by Clyde Butcher. All Rights Reserved. www.clydebutcher.com.
Copyright 2003 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America