Effetti del Global Change su crescita e funzionalitá delle foreste italiane Esperimenti e osservazioni F. Magnani 1, A. Barbati 2, M. Borghetti 3, G. Matteucci 4, S. Raddi 5, G. Tonon 6 Effetti del Global Change su crescita e funzionalitá delle foreste italiane Esperimenti e osservazioni F. Magnani 1, A. Barbati 2, M. Borghetti 3, G. Matteucci 4, S. Raddi 5, G. Tonon 6 1 Univ. Bologna, 2 Univ. Tuscia, 3 Univ. Basilicata, 4 CNR-IBAF, 5 Univ. Firenze, 6 Univ. Bolzano ”Too much of a good thing” Deposizioni di N ed ecosistemi forestali in Italia Roma, 16 maggio 2014 ”Too much of a good thing” Deposizioni di N ed ecosistemi forestali in Italia Roma, 16 maggio 2014

European (and NAmerican) forests are growing faster than they used to, and sequestering more C. Possible causes have been explored by the EU RECOGNITION project (Karjalainen et al. 2008): Global Change and forest growth C sequestration in Europe, : possible causes changes in the age structure of European forests: still ageing after WWII disturbance and past intensive management? changes in management practices (litter raking, residues collection, grazing …; fertilization) recovery of SOM and soil fertility Ciais et al. Nature Geoscience 2008 changes in forest species composition (eg close-to-nature forestry) growth (and perhaps NEP) stimulated by temperature changes GPP and growth affected by changes in solar irradiance and diffuse fraction growth and NEP stimulated by rising atmospheric CO 2 forests could benefit from atmospheric N deposition

New contrasting evidence on C-N interactions has emerged over the last few years. Focusing on annual rates, sensitivities range from < 70 (long-term fertilization experiments) to 200 g C / g N (regional transects). The reason could lie in the time frame being considered N deposition effects on forest growth and C sequestration N deposition effects: contrasting evidence Magnani et al. 2007, Nature Hyvönen et al. 2007, Biogeochemistry 50 (trees) + 20 (soil) g C / g N 200 g C / g N (total!)

The empirical observation of a co-variation between N addition and C sequestration has been questioned as spurious: -Sutton et al. (2008): N deposition could co-vary with temperature (real driver) -Hogberg (2012): N deposition could co-vary with background site fertility (real driver) through land-use history and development N deposition effects on forest growth and C sequestration the problem of co-variation with temperature and land-use These doubts can only be answered by a combination of approaches: 1.regional transects, variable N deposition (but also climate!): ICP L2, NFI 2.temporal changes in growth (chronosequences + growth rings): RECOGNITION 3.manipulative studies: long-term N fertilization 4.process-based models as integrating tools

MIUR - Ministero dell’Istruzione, dell’Università e della Ricerca PROGRAMMI DI RICERCA SCIENTIFICA DI RILEVANTE INTERESSENAZIONALE Effetti del cambiamento globale su produttività e forcing radiativo delle foreste italiane: metodi innovativi di analisi retrospettiva, sperimentale e prognostica #AcronimoIstituzione e CUPResponsabile 1UNIBOAlma Mater Studiorum – Università di Bologna (J38C ) Federico Magnani Claudio Ciavatta (Paola Gioacchini) 2UNIBASUniversità degli Studi della Basilicata (C38C ) Marco Borghetti Luigi Todaro (Tiziana Gentilesca) 3UNIBZLibera Università di Bolzano (B58C ) Giustino 4UNIFIUniversità degli studi di Firenze (B18C ) Sabrina 5UNITUSUniversità degli Studi della Tuscia (J88C ) Anna Barbati (Piermaria Corona) 6CNRCNR – IBAF (B88C ) Giorgio 6bMPFCRA – MPF(Patrizia Gasparini) (Gianfranco Scrinzi)

Task 1 – Modelling simulating effects of CO 2, N and climate at national level Forest growth and biogeochemistry estimated by HYDRALL-CENTURY model Distribution of reactive N deposition and its temporal dynamics ( ) estimated using the TM4 model CRU-TYN climate data SPADE-2 soil database for soil characteristics (texture, C, N) Model applied at 1 km resolution for the whole of Italy, by forest type (CORINE Level 4)

HYDRALL-RothC, spazializzato 1km a scala nazionale (modellizzazione diagnostica) HYDRALL- CENTURY, puntiforme (modellizzazione diagnostica) Task 1 – Modelling simulating effects of CO 2, N and climate at national level

Task 2 – Ecosystem fertilization review of N fertilization studies: a complex story  C n =  C g – Mortality  C n = net C sequestration in biomass  C g = gross C sequestration in biomass

Task 2 – Ecosystem fertilization growth response in coniferous species  C g response to additional N in ECM species Only experiments with at least 3 N levels (C, N1, N2) for non-linear effects (n=8) Pinus sylvestris, P. resinosa, P. banksiana, Picea abies Response normalized to common value of additional N Fitted segmented empirical model (Mitscherlich + linear decline)

Spinning the wheel: average sensitivity of net N mineralization to accumulated N input, possibly mediated by changes in soil C:N ratio Task 2 – Ecosystem fertilization review of N fertilization studies: long-term changes in soil processes

Task 2 – Ecosystem fertilization review of N fertilization studies: long-term changes in soil processes Forest long-term N fertilization in 2 Fagus sylvatica forests (+ 1 F. sylvatica, 1 Quercus pubescens by UNIBZ) Replicated (n=3) 30x30 m plots Combine with long-term monitoring at CONECOFOR sites Changes in forest (gross, net) increments, C accumulation in plants + soil Changes in soil processes (net N mineralization, nitrification + leakage) GHG emissions (CO 2, N 2 O, CH 4 ; ex-situ)

Task 3 – Reconstruction of past growth changes diachronic analysis in Fagus sylvatica chronosequences Analysis of past changes in tree and stand growth in Fagus sylvatica 5 chronosequences along Italy, associated with CONECOFOR sites Stem analysis for assessment of dominant height and total volume (see RECOGNITION) C and O isotope analysis for the assessment of functional determinants (transpiration, WUE) 2 additional Picea abies chronosequences in Italy and Germany

Effetti del Global Change su crescita e funzionalitá delle foreste italiane Esperimenti e osservazioni Effetti del Global Change su crescita e funzionalitá delle foreste italiane Esperimenti e osservazioni