STRESS PHYSIOLOGY AND FOREST PRODUCTIVITY FORESTRY SCIENCES Baas P, ed: New Perspectives in Wood Anatomy. 1982. ISBN 90-247-2526-7 Prins CFL, ed: Production, Marketing and Use of Finger-Jointed Sawnwood. 1982. ISBN 90-247-2569-0 Oldeman RAA, et a!., eds:, Tropical Hardwood Utilization: Practice and Prospects. 1982. ISBN 90-247-2581-X Den Ouden P and Boom BK: Manual of Cultivated Conifers: Hardy in Cold and Warm- Temperate Zone. 1982. ISBN 90-247-2148-2 Bonga JM and Durzan DJ, eds: Tissue Culture in Forestry. 1982. ISBN 90-247-2660-3 Satoo T and Magwick HAl: Forest Biomass. 1982. ISBN 90-247-2710-3 Van Nao T, ed: Forest Fire Prevention and Control. 1982. ISBN 90-247-3050-3 Douglas J: A Re-appraisal of Forestry Development in Developing Countries. 1983. ISBN 90-247-2830-4 Gordon JC and Wheeler CT, eds: Biological Nitrogen Fixation in Forest Ecosystems: Foundations and Applications. 1983. ISBN 90-247-2849-5 Nemeth MV: The Virus-Mycoplasma and Rikettsia Disease of Fruit Trees. ISBN 90-247-2868-1 Duryea ML and Landis TD, eds: Forest Nursery Manual: Production of Bareroot Seed lings. 1984. ISBN 90-247-2913-0 Hummel FC, ed: Forest Policy: A Contribution to Resource Development. 1984. ISBN 90-247-2883-5 Manion PD, ed: Scleroderris Canker of Conifers. 1984. ISBN 90-247-2912-2 Duryea ML and Brown GN, eds: Seedling Physiology and Reforestation Success. 1984. ISBN 90-247-2949-1 Staaf KAG and Wiksten NA: Tree Harvesting Techniques. 1984. ISBN 90-247-2994-7 Boyd JD: Biophysical Control of Microfibril Orientation in Plant Cell Walls. 1985. ISBN 90-247-3101-1 Findlay WPK, ed: Preservation of Timber in the Tropics. 1985. ISBN 90-247-3112-7 Samset I: Winch and Cable Systems. 1985. ISBN 90-247-3205-0 Leary RA: Interaction Theory in Forest Ecology and Management. 1985. ISBN 90-247-3220-4 Gessel SP: Forest Site and Productivity. 1986. ISBN 90-247-3284-0 Hennessey TC, Dougherty PM, Kossuth SV and Johnson JD, eds: Stress Physiology and Forest Productivity. 1986. ISBN 90-247-3359-6 Stress physiology and forest productivity Proceedings of the Physiology Working Group Technical Session. Society of American Foresters National Convention, Fort Collins, Colorado, USA, July 28-31, 1985 edited by THOMAS C. HENNESSEY Oklahoma State University, Stillwater, Oklahoma, USA PHILLIP M. DOUGHERTY University oj Georgia, Athens, Georgia, USA SUSAN V. KOSSUTH USDA Forest Service, Gainesville, Florida, USA JON D. JOHNSON University oj Florida, Gainesville, Florida, USA 1986 MARTINUS NIJHOFF PUBLISHERS a member of the KLUWER ACADEMIC PUBLISHERS GROUP DORDRECHT / BOSTON / LANCASTER Distributors for the United States and Canada: Kluwer Academic Publishers, 190 Old Derby Street, Hingham, MA 02043, USA for the UK and Ireland: Kluwer Academic Publishers, MTP Press Limited, Falcon House, Queen Square, Lancaster LAI lRN, UK for all other countries: Kluwer Academic Publishers Group, Distribution Center, P.O. Box 322, 3300 AH Dordrecht, The Netherlands Library of Congress Cataloging in Publication Data Stress physiology and forest productivity. (Forestry sciences ; v. Bibliography: p. 1. Trees--Physiology--Congresses. 2. Plants, Effect of stress on--Congresses. 3. Forest ecology--Congresses. 4. Forest management--Congresses. 5. Forest productivity --Congresses. I. Hennessey, Thomas C. II. Society of American Foresters. Physiology Working Group. III. Society of American Foresters. Convention (1985 Fort Collins, Colo.) SD395.S77 1986 634.9'6 86-8644 ISBN-13: 978-94-010-8469-7 e-ISBN-13: 978-94-009-4424-4 DOl: 10.1007/978-94-009-4424-4 SAF 86-04 Copyright © 1986 by Martinus Nijhoff Publishers, Dordrecht. Softcover reprint of the hardcover 1s t edition 1986 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Martinus Nijhoff Publishers, P.O. Box 163, 3300 AD Dordrecht, The Netherlands. v CONTENTS PREFACE . . . . . .......................... VII 1. INTRODUCTION S. G. Pallardy . 1 2. MOISTURE: EFFECTS OF WATER STRESS ON TREES R. O. Teskey and T. M. Hinckley .... 9 3. MOISTURE STRESS MANAGEMENT: SILVICULTURE AND GENETICS R. J. Newton, C. E. Meier, J. P. Van Buijtenen, and C. R. Mc Kinley .•.••...•....•..•. . . . . . . 35 4. NUTRIENTS: USE OF FOREST FERTILIZATION AND NUTRIENT EFFICIENT GENOTYPES TO MANAGE NUTRIENT STRESS IN CONIFER STANDS J. L. Troth, R. G. Campbell, and H. L. Allen •••..•.. . . . . . . 61 5. FOREST PESTS: INFLUENCE OF FOREST MANAGEMENT PRACTICES ON PEST POPULATION DYNAMICS AND FOREST PRODUCITVITY T. Evan Nebeker, D. R. Hous ton, and J. D. Hodges • . . • • • · ...... 101 6. FOREST PESTS: THE ROLE OF PHLOEM OSMOTIC ADJUSTMENT IN THE DEFENSIVE RESPONSE OF CONIFERS TO BARK BEETLE ATTACK P. J. H. Sharpe, R. J. Newton, and R. D. Spence . . • . •• •. ....... 113 7. LOW TEMPERATURE: PHYSICAL ASPECTS OF FREEZING IN WOODY PLANT XYLEM M. F. George and M. J. Burke. • • • . • . • • • • • • • • .. . ....... 133 8. MULTIPLE STRESS FACTORS: THE POTENTIAL ROLE OF SYSTEM MODELS IN ASSESSING THE IMPACT OF MULTIPLE STRESSES ON FOREST PRODUCTIVITY R. L. Graham, T. R. Fox, and P. M. Dougherty .... . . . . . . . . 151 9. FIRE: ITS EFFECTS ON GROWTH AND PHYSIOLOGICAL PROCESSES IN CONIFER FORESTS J. L. Chambers, P. M. Dougherty, and T. C. Hennessey · ...... 171 10. HERBICIDE STRESS: USE OF BIOTECHNOLOGY TO CONFER HERBICIDE RESISTANCE TO SELECTED WOODY PLANTS N. D. Nelson and B. E. Haissig .••...•••••••.• · . . . . . . 191 11. AIR POLLUTION: SYNTHESIS OF THE ROLE OF MAJOR AIR POLLUTANTS IN DETERMINING FOREST HEALTH AND PRODUCTIVITY 1. J. Fernandez . • • • . . • . . . • • • . • . . . • • • . . . . . . . . . . 217 ~I PREFACE Maintaining or increasing stand productivity is the concern of forest land managers worldwide. Consequently, there is increasing interest in understanding the impact of environmental stress on productivity and the development of management strategies that ameliorate or reduce the deleterious effects. Invited scientists gathered in Fort Collins, Colorado on July 30, 1985, to present the current state of knowledge regarding the impact of environmental stress on forest stand productivity. Particular attention was given to elucidating the mode of action by which individual stress elements reduce productivity. Environmental factors and the levels that constitute stressed (suboptimal) conditions in forest stands were identified, and the effects of stress intensity and duration on key stand parameters, including photosynthesis, respiration, assimilate partitioning, senescence and mortality, were emphasized. The role of genetics and silvicultural treatments in lessening the stress impact on stand productivity was presented, particularly in regards to alternative methods for environmental stress management. Modeling of stand dynamics in response to environmental stress was explored as an effective research and management tool. VIII Improved forest management practices will develop as we improve our understanding of the nature of important environmental stresses and as we comprehend their impact on tree and stand performance, manifested through physiological processes and genetic potential. This book is dedicated to such an understanding and comprehension. ThomM C. He.nnu-6e.y Phittip M. Vough~y SMa./'!. V. KOMuth Jon V. John!.:,on 1. INTRODUCTORY OVERVIEW S. G. PALLARDY Associate Professor, School of Forestry, Fisheries, and Wildlife, University of Missouri, Columbia, Missouri 65211 ABSTRACT Environmental stresses, both biotic and abiotic, commonly reduce plant growth below that which would be indicated by genetic potential. Physiological processes of plants integrate environment and heredity to control growth. The responses of physiological processes to environmental f~ctors are complex, but progress is being made in our understanding of these responses and in the ability to pre dict growth from knowledge of environmental modulation of plant physiology. The most successful physiologically oriented growth models have employed empirically determined relationships between dominant environmental factors and stand growth responses. The focus of this technical session will center on research directed toward improving management practices and growth modeling through a better understanding of fundamental physiological relationships among environ ment, hereditary potential of forest trees, and stand growth. 1.1 INTRODUCTION The environment presen~ed to forest stands, artifi cially or naturally regenerated, managed or unmanaged, commonly reduces growth and wood quality below the maximum attainable level. This fact is not obvious because these limitations are so pervasive that we have relatively few Contribution of. the Missouri Agricultural Experiment Station, Journal Series No. 9970 2 examples of unrestricted growth with which to compare the norm. In this technical session, the nature of important environmental limitations, how they influence stand perform ance through effects on individual trees, and contemporary research aimed at increasing forest stand growth and quality by modifying both plant and environment will be discussed. 1.2 STRESS CONCEPTS Although most people have an intuitive feeling for the concept of stress in biology, exact definitions are elusive. The majority of workers in stress research accept the concepts, if not terminology, advanced by Levitt (6). In Levitt's scheme, in which an analogy between biological and physical stresses is drawn, stress is defined as "any envir onmental factor capable of inducing a potentially injurious strain in living organisms." The strain(s) induced are physical and chemical responses within the organism that eventually produce the suite of macroresponses we observe as growth reduction, injury, or death. Continuing Levitt's mechanical analogy, organisms generally exhibit a capacity for elastic strain, where physiological responses are only temporarily altered, but return to normal after the stress is relieved, followed by plastic strain under greater levels of stress, where permanent alteration (and often injury and death) follow severe stress imposition and relief. The point at which elastic strain turns to plastic strain is called the "yield point" and it is important because it marks the level of stress where severe and irreversible effects begin. The yield point is not static but may change with moderate stresses of longer duration, as is exemplified by the process of osmotic adjustment (e.g., 8). The use of the term "strain" for the physiological res ponses of organisms to environmental factors has not been widely adopted; if so, we would be talking about "strain" management instead of stress management today, and as Paul Kramer has pointed out (4), no one uses or is likely to use the term~"plant water strain." In practice, stress is used 3 in a broad sense, describing both deleterious levels of environmental factors and the condition of the plant. Considerations of stress also include the influence of biotic as well as abiotic factors in the plant environment. Levitt's ideas do, however, provide a framework through which one can understand the response of forests to environmental influences. The forest scientist's and man ager's jobs are to understand the nature of these elastic and plastic responses and to work toward maintaining stands under minimal "elastic strain." 1.3 ENVIRONMENTAL AND GENETIC INFLUENCES ON STAND GROWTH The main objective of commodity forestry is to derive raw materials by manipulating the natural growth process through various management practices. In relating this session to practical considerations, two questions are par ticularly relevant: 1) What pattern of influence does the environment (broadly defined) have on growth? and 2) How are these environmental effects translated into observed changes in growth? Justus von Liebig, arguably the original agric ultural chemist, first addressed the former question when he formulated his Law of the Minimum: "The growth of a plant is dependent upon the amount of foodstuff [i.e., nutrients, water, etc.] that is presented to it in minimum quantities." A generalized response to an environmental factor is char acterized by a region of direct response to the factor fol lowed by a region of satiation or saturation (9). In the early part of this century Blackman (1) developed this idea further, demonstrating that the saturation level of a yield factor can be increased by the addition of a second limiting factor. These ideas provide a conceptual picture of the influence of environmental factors (particularly nutrition and light) on stand growth processes, but they by no means cover all situations. For example, growth responses to water availability would present an optimum response near field capacity, with reduced growth at lower soil water contents as water stress increases or at higher water