MONITORING AND EVALUATION OF FOREST ECOSYSTEM RESTORATION METSAÖKOSÜSTEEMI TAASTAMISE SEIRE JA ANALÜÜS DIANA LAARMANN A Thesis for applying for the degree of Doctor of Philosophy in Forestry Väitekiri filosoofiadoktori kraadi taotlemiseks metsanduse erialal Tartu 2014 Eesti Maaülikooli doktoritööd Doctoral Thesis of the Estonian University of Life Sciences MONITORING AND EVALUATION OF FOREST ECOSYSTEM RESTORATION METSAÖKOSÜSTEEMI TAASTAMISE SEIRE JA ANALÜÜS DIANA LAARMANN A Thesis for applying for the degree of Doctor of Philosophy in Forestry Väitekiri fi losoofi adoktori kraadi taotlemiseks metsanduse erialal Tartu 2014 Institute of Forestry and Rural Engineering Estonian University of Life Sciences According to verdict No 196 of July 14, 2014, the Doctoral Committee of the Agricultural and Natural Sciences of the Estonian University of Life Sciences has accepted the thesis for the defence of the degree of Doctor of Philosophy in Forestry. Opponent: Prof. Ioan Vasile Abrudan, PhD Transilvania University of Brasov Supervisors: Henn Korjus, PhD Institute of Forestry and Rural Engineering Estonian University of Life Sciences John A. Stanturf, PhD Center for Forest Disturbance Science Southern Research Station, USDA Forest Service Defence of the thesis: Estonian University of Life Sciences, room 2A1, Kreutzwaldi 5, Tartu on August 29, 2014, at 10:00. The English language was edited by John A. Stanturf and the Estonian by Moonika Kuusk. Publication of this thesis is granted by the Estonian University of Life Sciences and the Doctoral School of Earth Sciences and Ecology created under the auspices of European Social Fund. © Diana Laarmann 2014 ISSN 2382-7076 ISBN 978-9949-536-42-9 (trükis) ISBN 978-9949-536-43-6 (pdf) CONTENTS LIST OF ORIGINAL PUBLICATIONS .................................................7 ABBREVIATIONS .......................................................................................8 1. INTRODUCTION ...................................................................................9 2. REVIEW OF LITERATURE .............................................................12 2.1. Concept of ecological restoration for forest ecosystems ..........12 2.2. Naturalness of forest ecosystems ................................................14 2.3. Concept of novel ecosystem ..........................................................15 2.4. Research on forest restoration activities ....................................17 3. AIMS OF THE STUDY .......................................................................20 4. MATERIALS AND METHODS .......................................................21 4.1. Study area .........................................................................................21 4.1.1. Estonian Network of Forest Research Plots (ENFRP) .............................................................................21 4.1.2. Forest naturalness restoration plots (FNR) ...................22 4.1.3. Post-mining reclamation plots (PMR)............................23 4.2. Data collection ................................................................................24 4.2.1. Field measurements on permanent sample plots (PSP) ....................................................................................24 4.2.2. Biodiversity assessment .....................................................25 4.2.3. Soil sampling .....................................................................26 4.3. Data analysis ....................................................................................26 5. RESULTS .................................................................................................29 5.1. Deadwood fl ow as an indicator of forest naturalness .............29 5.2. Restoration effects on a forest ecosystem ..................................30 5.2.1. Effects on forest stand structure .....................................30 5.2.2. Effects on biodiversity ......................................................31 5.2.3. Effects on tree regeneration .............................................31 5.2.4. Effects on deadwood fl ow ................................................32 5.3. Evaluating restoration success .....................................................33 5.3.1. Soil properties .....................................................................33 5.3.2. Vegetation composition ....................................................34 5.3.3. Stand development.............................................................35 5.3.4. Evaluation of novel ecosystem.........................................36 6. DISCUSSION ..........................................................................................38 7. CONCLUSIONS ....................................................................................44 REFERENCES ............................................................................................46 SUMMARY IN ESTONIAN ....................................................................63 ACKNOWLEDGEMENTS......................................................................69 ORIGINAL PUBLICATIONS .................................................................71 CURRICULUM VITAE...........................................................................152 ELULOOKIRJELDUS ............................................................................155 LIST OF PUBLICATIONS .....................................................................158 6 LIST OF ORIGINAL PUBLICATIONS The thesis is based on the following papers; in the text references to them are given in Roman numerals. The papers are reproduced by the kind permission of the publishers. I Laarmann, D., Korjus, H., Sims, A., Stanturf, J.A., Kiviste, A., Köster, K. 2009. Analysis of forest naturalness and tree mortality patterns in Estonia. Forest Ecology and Management 258S: S187-S195. II Laarmann, D., Korjus, H., Sims, A., Kangur, A., Stanturf, J.A. 2013. Initial effects of restoring natural forest structures in Estonia. Forest Ecology and Management 304: 303-311. III Laarmann, D., Korjus, H., Sims, A., Kangur, A., Kiviste, A., Stanturf, J.A. 2014. Evaluation of afforestation development and natural colonization on a reclaimed mine site. Restoration Ecology [Submitted]. IV Sims, A., Kiviste, A., Hordo, M., Laarmann, D., Gadow, K.v. 2009. Estimating tree survival: a study based on the Estonian Forest Research Plots Network. Annales Botanici Fennici 46 (4): 336-352. The contributions from the authors to the papers are as follows: I II III IV Original idea DL, HK DL, HK DL, HK, AK, AK, AS JS Study design DL, HK, AK DL, HK All All Data collection DL DL DL All Data analysis DL, AS, HK, AK DL, HK, AS DL, HK, AS AK, AS Preparation of All All All All manuscript AK – Andres Kiviste; AS – Allan Sims; DL – Diana Laarmann; HK – Henn Korjus; JS – John A. Stanturf; All - all authors of the paper. 7 ABBREVIATIONS CControl plot CM Cause of mortality CMDI Diversity index of mortality causes CWD Coarse woody debris DBH Diameter at breast height DMi Deadwood mingling index DS Relative diameter DW Deadwood input ENFRP The Estonian Network of Forest Research Plots FNR Forest naturalness restoration plots GGap cutting GAM Generalized Additive Model GB Gap cutting and overburning GDW Gap cutting with deadwood input ISA Indicator Species Analysis MRPP Multiple Response Permutation Procedure NMS Non-metric Multidimensional Scaling PCA Principal Component Analysis PMR Post-mining reclamation plots PSP Permanent sample plot RDV5 The average recent deadwood volume for the last 5-year period 8 1. INTRODUCTION Modern forestry is shifting from timber production towards the service of a broader set of resource values and aims to fi nd the balance between conservation and management objectives of a forest ecosystem (Korjus, 2009). Silvicultural systems for timber production have caused fundamental changes in ecosystem structure and function associated with anthropogenic alterations of natural disturbance regimes (Esseen et al., 1992; Kuuluvainen, 2009). Increasingly, forest management is based on understanding of processes of natural disturbances, their effects for stand and landscape composition and structure, considering that this enables managers to reduce the negative impacts of timber harvest on biodiversity and thereafter maintain ecological functions (Attiwill, 1994). Ecological restoration as a research area has developed rapidly over the past few decades (Harris et al., 2006; Hobbs et al., 2011). The objective of ecological restoration is to re-create a self-supporting ecosystem which existed previously and is resilient to contingent damage (Urbanska et al., 1997) and to maintain the system in a desirable state or moving away from an undesirable state. Forest restoration is widely practiced in North America (Stanturf et al., 2009; Bolton and D’Amato, 2011; Humber and Hermanutz, 2011; White et al., 2011), Australia (Grant et al., 2007), and in Europe, particularly in Finland (Kuuluvainen et al., 2005), the United Kingdom (Hancock et al., 2009), and Sweden (Olsson and Jonsson, 2010). Forest restoration not only aims for stand re-establishment, but to initiate natural processes and foster natural structures and species composition (Stanturf and Madsen, 2002; Vanha-Majamaa et al., 2007; Stanturf et al., 2014). Restoration is activity which can improve conservation efforts in protected areas in order to enhance quality and quantity, to improve connectivity between fragmented areas and create buffer zones between protected and managed forest areas (Kuuluvainen