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Michael Bredemeier ● Shabtai CohenDouglas L. Godbold ● Elve LodeViliam Pichler ● Patrick SchleppiEditors

Forest Management and the Water Cycle

An Ecosystem-Based Approach

EditorsMichael BredemeierUniversität GöttingenForest Ecosystems Research CentreUniversity of GöttingenBüsgenweg 2, D-37077 GöttingenGermanymbredem@gwdg.de

Douglas L. GodboldEnvironment Centre WalesBangor UniversityGwynedd, LL57 2UWUKd.l.godbold@bangor.ac.uk

Viliam PichlerDepartment of Natural EnvironmentFaculty of ForestryTechnical University in ZvolenT.G. Masaryka 24, 960 53 ZvolenSlovakiapichler@vsld.tuzvo.sk

Shabtai CohenInstitute of Soil, Water and Environmental SciencesARO Volcani CenterPOB 6, Bet Dagan 50250Israelvwshep@agri.gov.il

Elve LodeTallinn UniversityInstitute of EcologyUus Sadama 5, 10120 TallinnEstonia and Swedish University of Agricultural Sciences, Department of Soil and EnvironmentP.O.Box 7001, SE-75007 Uppsala Swedenelve.lode@tlu.ee

Patrick SchleppiSwiss Federal Institute for ForestSnow and Landscape ResearchZürcherstr. 111, CH-8903 BirmensdorfSwitzerlandschleppi@wsl.ch

ISSN 0070-8356ISBN 978-90-481-9833-7 e-ISBN 978-90-481-9834-4DOI 10.1007/978-90-481-9834-4Springer Dordrecht Heidelberg London New York

Library of Congress Control Number: 2010938711

© Springer Science+Business Media B.V. 2011No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work.

Cover illustration: A reductionist view of forest-water interactions. Two foci of forest management are provisions of pure drinking water and the danger of floods. Painting by Shalhavit S. Cohen.

Printed on acid-free paper

Springer is part of Springer Science+Business Media (www.springer.com)

v

Contents

Forest Management and the Water Cycle – Introduction to the Challenge ............................................................................................... ixMichael Bredemeier

Section I Forest and Water – Tree to Small Catchment Processes in a Changing Environment

1 Introduction ............................................................................................. 3 Patrick Schleppi

2 Hydrological Effects on Below Ground Processes in Temperate and Mediterranean Forests ............................................ 5

Boris Rewald, Panagiotis Michopoulos, Lise Dalsgaard, David L. Jones, and Douglas L. Godbold

3 Above Ground Processes: Anticipating Climate Change Influences ................................................................................... 31

Mauro Centritto, Roberto Tognetti, Ernst Leitgeb, Katarina Střelcová, and Shabtai Cohen

4 Field Studies of Whole-Tree Leaf and Root Distribution and Water Relations in Several European Forests .............................. 65

Jan Cermak and Nadezhda Nadezhdina

5 Forested Water Catchments in a Changing Environment .................. 89 Patrick Schleppi

6 Forest Development in the European Alps and Potential Consequences on Hydrological Regime ................................................ 111

Christine Alewell and Peter Bebi

vi Contents

7 Effects of Climate Change on the Vulnerability of Norway Spruce Stands – Soil Hydrological Constraints for Forest Management in Austria’s Lowlands .................................... 127

Karl Gartner, Michael Englisch, and Ernst Leitgeb

8 Observed Climate Change in Croatia and Its Impact on the Hydrology of Lowlands ............................................................... 141Boris Vrbek, Ivan Pilaš, and Nikola Pernar

9 The Case of Yatir Forest ......................................................................... 163Gabriel Schiller

10 How Mediterranean Deciduous Trees Cope with Long Summer Drought? The Case of Quercus pyrenaica Forests in Western Spain ................................... 187Gerardo Moreno, Juan F. Gallardo, and María Ángeles Vicente

Section II Forest Structures, Management and Water Fluxes

11 Introduction ............................................................................................. 205Viliam Pichler

12 Changes in Forest Cover and its Diversity ............................................ 209Viliam Pichler, Paulo Godinho-Ferreira, Tzvetan Zlatanov, Magdaléna Pichlerová, and Juraj Gregor

13 Afforestation Strategies with Respect to Forest–Water Interactions ................................................................. 225Yannis Raftoyannis, Michael Bredemeier, Rasa Buozyte, Norbert Lamersdorf, Andreas Mavrogiakoumos, Edda Oddsdóttir, and Ivaylo Velichkov

14 Tree Species’ Tolerance to Water Stress, Salinity and Fire ................. 247Martin Lukac, Margus Pensa, and Gabriel Schiller

15 Overland Flow, Soil Erosion and Stream Water Quality in Forest Under Different Perturbations and Climate Conditions .......................................................................... 263Meni Ben-Hur, Cristina Fernandez, Sakari Sarkkola, and Juan Carlos Santamarta Cerezal

16 Forest Management Effects on Below-Ground Hydrological Processes ........................................................................... 291Viliam Novák, Viliam Pichler, Elisabeth Graf-Pannatier, Edward P. Farrell, and Marián Homolák

viiContents

17 Adjustment of Forest Management Strategies to Changing Climate ............................................................................... 313Špela Planinšek, Leena Finér, Antonio del Compo, Jorge Alcazar, Cristina Vega-García, Dimitar Dimitrov, and Jozef Capuliak

Section III Scales and Approaches for Forest – Water Interactions

18 Introduction ............................................................................................. 333Elve Lode

19 Forest Management and the Water Cycle: An Integrated Introduction to Scaling .................................................. 335Elve Lode, Matthias Langensiepen, Jüri Roosaare, Gebhard Schueler, and Harri Koivusalo

20 Multidimensionality of Scales and Approaches for Forest–Water Interactions................................................................ 351Ivan Pilaš, Karl-Heinz Feger, Urša Vilhar, and Andreas Wahren

21 Fundamentals of Model Scaling in Forest Ecology .............................. 381Matthias Langensiepen

22 Up- and Downscaling Model Approaches for Water Relations in Forest Management from Plot to Landscape Level.................................................................................. 397Chris S. Eastaugh, Stephan A. Pietsch, Richard Petritsch, Elisabeth Pötzelsberger, and Hubert Hasenauer

23 A Small Catchment Scale Approach for Modeling Effects of Forest Management on Water Cycle in Boreal Landscape ............. 419Harri Koivusalo, Hannu Hökkä, and Ari Laurén

24 Large Scale Approach to Forest and Water Interactions .................... 435Gebhard Schüler, Laurent Pfister, Michael Vohland, Stephan Seeling, and Joachim Hill

25 Model-Based Assessment of Forest Land Management on Water Dynamics at Various Hydrological Scales – A Case Study ................. 453Andreas Wahren and Karl-Heinz Feger

26 Typological Up-Scaling of Wooded Peatlands ...................................... 471Elve Lode, Jüri Roosaare, and Margus Pensa

viii Contents

27 Difficulties of Scaling in Forest and Water Management in Urban Areas: Social and Institutional Dimension ........................... 497Sultan Bekiroglu and Ömer Eker

28 Synthesis and Outlook ............................................................................ 507Shabtai Cohen and Michael Bredemeier

Taxonomic Index ............................................................................................. 513

Subject Index ................................................................................................... 515

ix

Forest Management and the Water Cycle – Introduction to the Challenge

Michael Bredemeier

How and how much can forest management contribute to optimize the water cycle with respect to resource provision on the one hand, and mitigation of water related hazards on the other? This question is the golden thread along which the contribu-tions in this volume are strung. The book synthesizes research on the interactions of forest management and the water regime of forests in Europe and beyond, cover-ing geographic and climatic gradients from Iceland to Israel and from southern Spain to Estonia and Finland. The collection of people and their ideas on this topic was made possible through the COST Action “Forest Management and the Water Cycle (FORMAN)”, which was launched in 2007 and will run until 2011. The acronym COST stands for “cooperation in the field of scientific and technological research”. It is the longest established funding scheme of the EU for scientific cooperation and exchange in Europe and beyond, and has run for more than 35 years (http://www.cost.esf.org/).

The scientific consortium of FORMAN aims at the enhancement of knowledge on forest–water interactions in Europe, and the elaboration of science-based guide-lines for the improvement of the management of forests in their delivery of the ecosystem service “purification and storage of water”.

Water is unquestionably a key resource for all life on earth, probably the most important one besides of solar radiation. These two together basically constitute climate at any given place on earth, which in turn determines natural potential pro-ductivity of ecosystems.

However, besides the resource aspect, a potential hazard to the human popula-tion is also related to water. Along river systems and in their larger floodplains, peak flow rates can entail devastating floods. It is speculated that the frequency and intensity of such floods are currently increasing because of global climatic change and a concomitant amplification of extreme weather situations (IPCC 2007).

Forests are an essential element of the European cultural landscapes. They cover about a third of Europe’s land area (27% in central, 32% in southern and 50% in

M. Bredemeier Forest Ecosystems Research Centre, University of Göttingen, Büsgenweg 2, D-37077, Göttingen, Germany

x Forest Management and the Water Cycle – Introduction to the Challenge

northern Europe according to the UN Food and Agricultural Office’s 2000 Forest Resources Assessment Report). With respect to the water resource, the importance of forests has to be weighted even higher than their proportion of total area, since forested landscapes are the preferred sources for generation, storage and export of drinking water to supply the human population.

Almost all forest land in Europe is more or less intensively managed, “natural forest” in a strict sense can hardly be found, a fact which is not well known to the general public. Nevertheless, forests are highly valued for their relative closeness to natural ecosystems, and for the various services that they provide. Among those services, water regulation and supply from forest soils and aquifers is one of the most prominent. Forest ecosystems supply the high quality drinking- and process-water resource for the human population and also safeguard against both flooding and erosion by retaining water and thus delaying and mitigating peak flows.

The protective function of forests with respect to water quality and water-related hazards is potentially at risk under a changing climate and changing land-management practices. The water budgets of forest ecosystems are heavily dependent on climate and forest structure. The latter is determined by the management measures applied in the forestry sector, such as tree species selection, stand structure and density management, harvesting methods, etc. In the next decades, both climate and forest-management practices are expected to change. The intention in many European countries will be to establish forest stands that are closer to the potential natural forest vegetation. This means a general trend of increasing the area of broad-leaved and mixed stands while reducing the area of mono-specific conifer plantations that had been favoured in many European countries in the past. In other European countries, however, there are large campaigns for (re)afforestation, which partly comprise monocultures. All these different trends have to be considered when assessing the overall forest–water interaction in Europe. The chapters in this volume highlight them, both in the form of thematic reviews and of selected regional case studies.

Climatic change as the major driver will most probably result in a stronger pre-cipitation gradient from (north)western to (south)eastern Europe – corresponding to the amplification of an already given gradient (Fig. 1).

The combination of changing forest-management practices with a changing physical and chemical climate is forming an unprecedented collection of manage-ment constraints for European forests. The contributions in this book cover envi-ronmental gradients from the humid Atlantic to the dry continental and Mediterranean climates and from lowlands to high mountains. Forest–water relations over these climatic gradients, scenarios of climatic changes, and the influence of forest- management options are evaluated, with scales of study ranging from local intensive plot measurements to regional and continental (European) integration.

The book is divided into three sections, reflecting three levels of forest and water interactions. The first section deals with the basic physical, chemical and biological processes. The topics cover the soil/water-biota-atmosphere continuum in the forest. The second section deals with individuals and communities, and with management practices that are usually applied at this scale. Thus, this section

xiForest Management and the Water Cycle – Introduction to the Challenge

describes the species composition of the various plant communities and afforesta-tion campaigns, management of these communities and soil management. It is the section closest to the application of scientific expertise in practical forest manage-ment. The third section targets the large scale view of forests, e.g. river sized watersheds. First, the different approaches for applying small scale understanding of the systems to larger scale problems are addressed. Then, topics like the hydro-logical consequences of forestry practices are considered.

The first section of this book comprises a systematic review of the affected processes in different ecosystem compartments, from the physiologically active interfaces below- and aboveground, to the forest catchment scale, and further to freshwater chemistry and biology in forest areas, which are likely to be affected by climatic- and system changes.

The second part of the section turns to case studies in this context, resulting from original research contributed by members of the COST consortium.

Rewald et al. put a focus on “Hydrological Effects on Below Ground Processes in Temperate and Mediterranean Forests”. The belowground part of a forest ecosys-tem is intrinsically difficult to study but more and more good methods have become available in addition to longer established parameters. A challenge is to quantify the variability of physiological and anatomical root traits in heterogeneous soil envi-ronments as well as interactions with mycorrhizas.

Fig. 1 Simplified general scenario of amplification of a climatic gradient across Europe; coun-tries in red are COST Action “Forman” members, Israel is a member out of the map range

xii Forest Management and the Water Cycle – Introduction to the Challenge

Centritto et al. turn to the complementary part, “Above Ground Processes – Anticipating Climate Change Influences”. They look in detail at leaf to tree level processes and the effects that rising temperature, drought and extreme weather events exert upon them, but also widen the focus to address species differences in water relations and canopy structure across Europe.

Jan Čermák and Nadezhda Nadezhdina present a strong methodological scope in their chapter “Field Studies of Whole-Tree Leaf and Root Distribution”, starting from individual organs (roots or branches) but finally covering whole tree and stand level measurements up to the landscape scale.

Schleppi et al. in their contribution “forested water catchments” bring in the whole-catchment scale and demonstrate the usefulness of experiments at that level, as catchments are usually “integrators” of different ecological and biogeochemical effects in producing their runoff.

Christine Alewell and Peter Bebi write on “Forest Development in the European Alps and Potential Consequences on Hydrological Regime”. They cite the fine meta-phor of mountains as our “water towers” and investigate how forest regrowth, often occurring after pasture land abandonment in the Alps will affect their function.

Ernst Leitgeb and Karl Gartner take us back down from the mountains, turning to “vulnerability of Norway spruce in Austria’s lowlands”. The extremely warm sum-mer of 2003 highlighted the reduced vitality of Norway spruce in the lower parts of Austria during hot and dry years. It is very important to find alternative silvicultural options to Norway spruce stands in this and many other European regions.

Boris Vrbek and Ivan Pilaš work on water table management in lowland forests of south-eastern Europe. They show how indices for recognition of the onset of drought should be developed and implemented, and advocate conservation of water surplus from the winter season further into the growing season when unfavourable conditions of water scarcity occur.

Gabriel Schiller turns our attention to the dry environments in his chapter “The Case of Yatir Forest”. This case study is located in Israel and consists of Pinus halepensis (Mill.) forest, where he measured water use employing the heat pulse method.

Finally in the first section, Moreno et al. show us “How Mediterranean Deciduous Trees Cope with Long Summer Drought: the Case of Quercus pyrenaica Forests in Western Spain”. This species seems well adapted to surviving summer drought while maintaining photosynthetic activity and apparently having a non-conservative water consumption. The authors explain the strategy and mechanism of survival of those forests.

The second section examines more closely the forest management side of the overall issue with due consideration of its potentials as well as its limitations. As water availability might change dramatically in Europe and adjacent regions, it will affect existing tree species and their ability to cope with a lack or excess of water, soil salinity and fire frequency and intensity. Tree species and provenances which are the most suitable to deal with water stress (both under excess and scarcity) are identified and options for their future management are evaluated.

Considerable changes in European forests’ tree species composition and struc-tures will be driven by silvicultural adaptation strategies to climatic change over the

xiiiForest Management and the Water Cycle – Introduction to the Challenge

next decades. Also optimisation of afforestation and reforestation with respect to forest–water interactions is comprised, as well as mitigation of detrimental conse-quences for surface- and groundwater quality, water yield, groundwater recharge, runoff and erosion control in forested landscapes.

Pichler et al. start with an overview of “Changes in Forest Cover and its Diversity”. This chapter provides an outline of the natural forest cover dynamics in Europe, as well as of its past, current and projected changes, which are driven by the two main factors climatic change and land use change.

Raftoyannis et al. contribute a chapter on “Afforestation Strategies with Respect to Forest–Water Interactions”. Afforestation may offer attractive ecological per-spectives, such as better peak flow control combined with biodiversity support, along with attractive economic returns, for instance from energy wood grown in short rotations. This is particularly the case in the moister environments of Europe with ample precipitation supply. However, where water supply gets more limited, a situation of distinct trade-off may emerge very quickly.

Lukac et al. give information on “Tree Species’ Tolerance to Water Stress, Salinity and Fire”. They describe tree species and provenances used in European forestry practice which are the most suitable to deal with those stressors and constraints.

Ben-Hur et al. write on “Overland Flow, Soil Erosion and Stream Water Quality in Forest Under Different Perturbations and Climate Conditions”. They delineate the relationships between forest and climate conditions, and their effects on runoff, soil erosion and stream water quality, when subjected to various perturbations. The discussion addresses water-driven soil erosion.

Novák et al. make a contribution on the “Forest Management Effects on Below-Ground Hydrological Processes”. They point out the value of comparative studies in managed forests and forests following natural dynamics. Important factors related to the forests’ management are identified and their influence described both qualitatively and quantitatively.

Concluding the second section, Planinšek et al. expand on “Adjustment of Forest Management Strategies to Changing Climate”. They put a focal point on the impacts of forest management and climate change on the interaction of forests and surface and ground water in boreal, temperate and Mediterranean regions of Europe and discuss measures to mitigate negative impacts. Approaches can be quite differ-ent as the forest management goals and strategies differ between regions.

The third section has questions of scaling at its core, starting with the important task of up-scaling from small resolution process information and ending at large spatial scale assessments. Scaling is an important tool for integration of research results with management options and society needs. The different scales from small headwater catchment to major river basin are all relevant in the assessment of for-est–water interactions. The authors demonstrate that scales can serve as a structur-ing principle, both in the data-gathering process and in evaluation and assessment exercises. For smaller catchments and at plot-scale, there are frequently hydrologi-cal case studies available, whereas on the larger scale, remote sensing techniques and blending of available information layers from maps and GIS are often applied.

xiv Forest Management and the Water Cycle – Introduction to the Challenge

Starting from the fundamentals of scaling, authors in Section III review up-scaling approaches for the water fluxes in forests, and in particular small scale and large scale approaches to forest and water interactions. General papers are followed by case studies related to scaling applications.

The section starts with an introductory overview on fundamental concepts and techniques of scaling including application of GIS in forest ecosystems and wet-lands given by Elve Lode, Matthias Langensiepen, Jüri Roosaare, Gebhard Schueler and Harri Koivusalo.

Ivan Pilaš et al. refer to the EU Floods Directive in their chapter “Multidimensionality of Scales and Approaches for Forest–Water Interactions”. The Directive (EC 2007) emphasises better utilization of forest hydrological func-tions. The mitigation potential of forests should be developed and be aimed at reducing runoff formation or mitigating adverse impacts of running waters. To alleviate the effect of drought in the future, forest management has to evaluate vari-ous adaptive strategies for drought impact management.

Matthias Langensiepen expands on the “Fundamentals of Model Scaling in Forest Ecology”. He summarizes statistical techniques for scale identification and presents the establishment of scaling laws from a mathematical point of view. Structure and function are stressed as important concepts for understanding tree responses to changing environments. Methods of translating models across spatial scales are categorized in the final part of this chapter.

Chris Eastaugh et al. put the focus on “Up- and Downscaling Model Approaches”. This is indeed a very central and crucial scale range as management measures are usually applied at the plot scale and ecological (as well as aesthetical) effects of forest management are prominently recognized at the landscape level. The authors put a special focus on how water-related processes can be integrated so that point or plot information may be generalised to larger scale applications.

Harri Koivusalo et al. write on “A Small Catchment Scale Approach … in Boreal Landscape”. This chapter demonstrates how a forest growing on peatland or mineral soil in the boreal region can be parameterised as a hydrological response unit (HRU), and how environmental effects and effects of forestry on the water cycle can be discerned and described.

Gebhard Schüler et al. contribute a “Large Scale Approach to Forest and Water Interactions”. Integrated land and water management at larger scale needs to find a way of combining technical (engineering) watershed management and a scientific based precautionary land-use management. A large scale European approach across political borders was laid down by the European Water Framework and Floods Directives.

Andreas Wahren et al. write on “Model-Based Assessment of Forest Land Management on Water Dynamics at Various Hydrological Scales – A Case Study”. They point out that emphasis should be put on the detection of synergy effects between a good ecological status of the water bodies and flood protection. This approach combines socio-economic methods with state-of-the-art hydrological modelling and the available information about climatic change.

xvForest Management and the Water Cycle – Introduction to the Challenge

Elve Lode et al. contribute information on “Typological Up-Scaling of Wooded Peatlands”. This chapter introduces GIS based case study results of the small wooded Estonian Selisoo mire, located in the eastern part of Estonia and belonging to the Ramsar sites’ Muraka mire complex.

In the final chapter of Section III, Sultan Bekiroglu and Ömer Eker go deepest into the societal context with their contribution “Difficulties of Scaling in Forest and Water Management in Urban Areas: Social and Institutional Dimension”. In this study, interactive connections between water and forest management on the one hand and the complexities among socio-economic-environmental and institutional systems on the other are highlighted with some examples from European urban environments.

Acknowledgement All authors who have contributed to this volume greatly and gratefully acknowledge the support through COST Action FP 0601 “Forest Management and the Water Cycle (FORMAN)”, and through the numerous national and international funding programs and institutions by which their work was supported.