UNIVERSITÀ DEGLI STUDI DI TORINO FACOLTA’ DI AGRARIA DOTTORATO DI RICERCA IN SCIENZE AGRARIE, FORESTALI ED AGROALIMENTARI CICLO: XX CURRICULUM: PIANIFICAZIONE FORESTALE, SELVICOLTURA E TECNOLOGIA DEL LEGNO DEVELOPING A PRESCRIBED BURNING EXPERTISE IN ITALY: LEARNING FIRE EXPERIMENTS Davide Ascoli TUTOR Prof. Giovanni Bovio COORDINATORE DEL CICLO Prof. Vittorino Novello ANNI ACCADEMICI 2005; 2006; 2007 ii DEVELOPING A PRESCRIBED BURNING EXPERTISE IN ITALY: LEARNING FIRE EXPERIMENTS Davide Ascoli iii iv “…cold, and moving carefully on the tracks, fully aware of his entire body, his face, his mouth, his eyes stuffed with blackness, his hears stuffed with sounds,…,he saw the fire ahead. The fire was gone, then back again, like a winking eye. He stopped, afraid he might blow the fire out with a single breath. But the fire was there and he approached warily, from a long way off…The small motion, the white and red color, a strange fire because it meant a different thing to him. It was not burning. It was warming. He saw many hands held to its warmth, hands without arms, hidden in darkness…He hadn’t know fire could look this way. He had never thought in his life that it could give as well as take…” Ray Bradbury, Fahrenheit 451. v vi Abstract Prescribed burning is one of the main issue of current fire research in Mediterranean countries. Several benefits are expected: fire hazard abatement, nature conservation management, carbon emission reduction. Nevertheless in Italy very few knowledge is available about prescribed burning applicability. The develop of new expertises is required. To minimize the risk with introducing prescribed burning in fire management practices it is necessary to conduct learning experiments. Manipulative fire experiments which test the effect of different prescribed fire regimes (frequency, seasonality, intensity) have proved to be useful throughout world ecosystems. With the objective to develop and transferring expertises about the design of prescribed fire experiments two studies were carried out. Both studies adopted a microplot scale analysis of fire behaviour for correlation with ecological effects on vegetation. The first study dealt with Calluna vulgaris heathlands conservation in North West (NW) Italy. These heathland are under threat because of tree and grass encroachment as a consequence of extensive management. Like Muirburning in Scotland fire could be a suitable management tool in NW Italy. The experiment, started in 2004 at the Managed Nature Reserve of Vauda, Regione Piemonte, was designed to test the effect of fire frequency, backfire and headfire treatments on tree mortality and Calluna regeneration. The microplot scale analysis of fire behaviour enabled to cope with fire heterogeneity quantifying fine fuel consumption, rate of spread, flame height, fireline intensity and flame pick- temperatures with spatial and temporal resolution. An estimate of temperature- residence time profiles using infra-red termography was attempted. On the basis of short-term monitoring of vegetation responses to fire treatments a set of preliminary prescriptions for heathland conservation management by prescribed fire was established. The second study dealt with coarse woody debris (CWD) consumption by experimental fire in tropical savannas of Northern Australia. The experiment was carried out in the frame of a research project of the Tropical Ecosystem Research Centre (CSIRO) which studies effects of early and late dry season fires on savanna ecosystem. Through the manipulation of fine fuels a wide range of fireline intensity and temperature-residence time profiles was obtained. A simplified CWD consumption model was studied. Results were not very substantial, however this experience enabled to test new methodologies which implemented the experiment design at Vauda. Despite constraints this thesis demonstrated that is possible to develop research in the field of prescribed burning in Italy and hopefully will stimulate further discussion in order to improve knowledge and thereby future management. vii viii Acknowledgments I would like to thank… …the University of Torino for giving me the opportunity to carry out three years of research in the frame of the doctorate; …prof. Giovanni Bovio of Dep. Agroselviter for supervising me in this study; …the colleagues Rachele Beghin, Andrea Cavallero, Riccardo Ceccato, Davide Cugno, Matteo Garbarino, Emanuele Lingua, Giampiero Lombardi, Michele Lonati, Raffaella Marzano, Renzo Motta, Nayara Mello, Giorgio Vacchiano, Marta Vergilio and Matteo Zerbini for fruitful discussions, help in field work, paper editing and support; …the Ente di Gestione dei Parchi e delle Riserve Naturali del Canavese, Regione Piemonte, for financing the research carried out at the Riserva Naturale Orientata della Vauda; …dott. Antonio Aschieri of Ente di Gestione dei Parchi e delle Riserve Naturali del Canavese, Regione Piemonte, for introducing me to Calluna heathland conservation management; …the Tropical Ecosystem Research Centre, CSIRO Sustainable Ecosystems, Darwin, Northern Territory, Australia, for giving me the opportunity to carry out 6 months of research taking advantage of its facilities; …dott. Richard J. Williams principal research scientist of TERC, for introducing me to tropical savannas fire management and paper editing; …Sandra Bernard, Ricardo Ildefonso de Campos, Aymeric Malliot, Immanuel Huschatz, Alexander Hanke, Sandrine Le Gars, Jean-Charle Perquin for work done together in the frame of the ‘Burning for Biodiversity Program’ of TERC; …the Corpo Forestale dello Stato and Corpo Volontari Antincendi Boschivi, Regione Piemonte, for the collaboration in carring out fire experiments at the Riserva Naturale Orientata della Vauda. …finally my family which always encouraged me. ix x Table of Contents Title page ……………………………..………………………………….……….…….i Abstract …………………….……………………………………….…………….…..vii Acknowledgements ………………….…...……………..………..………..…….…ix Table of contents ………..……………………………..………….……..…....……xi 1. Introduction ........................................................................... 1 1.1. Fire experiments for Calluna heathland conservation management in NW Italy……………………………………………………………………………..2 1.2. Modelling coarse woody debris consumption by fire experiments in tropical savannas of Northern Australia.............................................. 4 1.3. Objectives........................................................................................ 5 2. Prescribed burning ......................................................... 6 2.1. Fire and civilization........................................................................... 6 2.2. Forest fire policies in North America and Australia.............................. 9 2.3. Prescribed burning in Europe.......................................................... 11 2.4. Prescribed burning policy and research in Italy................................. 15 3. Prescribed fire experiment design ......................... 18 3.1. Conservation management by prescribed fire................................... 18 3.2. Fire and plants............................................................................... 21 3.2.1. Adaptive traits of plants........................................................... 22 3.2.2. Fire and plant succession dynamics......................................... 23 3.3. Fire behaviour and effects............................................................... 25 3.3.1. Fire behaviour modelling......................................................... 26 3.3.2. Fuel modelling........................................................................ 28 3.4. Fire behaviour characterization by fire experiments.......................... 30 3.4.1. Fire spread............................................................................. 30 3.4.2. Heat processes....................................................................... 32 3.4.3. Coping with fire heterogeneity.................................................. 36 xi 4. Fire experiments for Calluna heathland conservation management in NW Italy ....... 38 4.1. Introduction.................................................................................... 38 4.1.1. Calluna vulgaris Hull................................................................ 38 4.1.2. Calluna vulgaris distribution and ecology.................................. 39 4.1.3. Calluna heathland conservation issues in Europe...................... 41 4.1.4. Moorlands management by fire in Scotland: ‘Muirburning’.......... 42 4.1.5. Calluna conservation management in NW Italy......................... 46 4.1.6. Calluna conservation management at the MNR of Vauda .......... 46 4.1.7. Fire research issues and objectives at Vauda ........................... 50 4.2. Material and methods..................................................................... 52 4.2.1. Study site............................................................................... 52 4.2.2. Experimental design................................................................ 53 4.2.3. Experimental sites fire history .................................................. 54 4.2.4. Fuel sampling......................................................................... 54 4.2.5. Burning procedures................................................................. 57 4.2.6. Weather data collection........................................................... 58 4.2.7. Fire spread estimation............................................................