TSEC-Biosys Annual Meeting at Imperial College, December 08 Theme 2.2: Modelling the productivity of short rotation coppice (SRC) M.J. Aylott, G. Taylor University of Southampton, UK E. Casella Forest Research, UK

Contents 1.Introduction 2.Future Climate Effects 3.Process Model 4.Theme interaction 5.Publications

First modelling phase (Finished July 07) Develop an empirical model to measure current productivity and spatial capacity of SRC in the UK Second phase (Aug 07-Mar 09) Parameterise the ForestGrowth process model for SRC and model yield changes in future climates by incorporation of the UKCIP02/08 future climate scenarios 1. Introduction

2. Future Climate Effects on Yield Climate change/yield studies have primarily focussed on single interactions rather than whole system processes, as a result we know little as to how future climates will effect yields Understanding whole system, species-specific relationships between climate and production is important in order to aid breeders, guide policy decisions and help develop the future of the industry

2. Climate Variable: CO2 Carbon Dioxide is understood to have a fertilisation effect on crops FACE experiments have shown elevated atmospheric CO 2 (550ppm) could contribute to an increase of up to 27% in poplar yields (Calfapietra et al., 2003), however other similar studies have shown the effect may be between -16 and +53%

2. Climate Variable: CO2 SpeciesGenotypeLocationTrial typeConditionsYield effectReference P. deltoides x P. nigra RobustaAntwerp, Belgium OTC – 2 yr old Organic black horticultural soil + irrigated + fertiliser + 700ppm CO2 +43%Ceulemans et al., 1996 P. trichocarpa x P. deltoides Beaupré +48% P. tremuloides-Wisconsin, USA ECR – 1 yr old (pots) Forest topsoil + irrigated + fertiliser + 660ppm CO2 + 53%Kinney and Lindroth, 1997 P. deltoides x P. nigra EugeneiMichigan, USA OTC – 1 yr old Low fertility topsoil + irrigation + fertiliser + 750ppm CO2 + 25% (low N); + 49% (high N) Lussenhop et al., 1998 P. deltoides x P. nigra DN-33Michigan, USA OTC – 1 yr old 2:1:1 Peat: sand: vermiculite mixed soil + irrigated + fertiliser + 550ppm CO2 - 16%Dickson et al., 1998 DN-34+29% DN-70+34% DN-74+34% P. nigra x P. maximowiczii NM-6+36% P. tremuloides-Michigan, USA OTC – 3 yr old Low fertility topsoil + fertiliser + 710ppm CO2 + 16% (low N); + 38% (high N) Zak et al., 2000 P. trichocarpaIdunnSouthern Iceland CTC – 3 yr old Andisol soils + fertiliser + 710ppm CO2 + 47%Sigurdsson et al., 2001 P. alba2AS11Central Italy FACE – 3 yr old Xeric Alfisol loam soil + irrigated + 550ppm CO2 + 15%Calfapietra et al., 2003 P. nigraJean Pourtet+ 27% P. x euramericanaI %

2. Climate Variable: Temperature Temperatures are likely to rise in the future – with summer temperatures increasing at a greater rate than those in winter Higher temperatures are known to bring forward budburst and increase photosynthesis but will also increase transpiration & respiration rates Source: UKCIP02 Climate Change Scenarios

2. Climate Variable: Precipitation Future predictions for lowland England suggest decreased precipitation and increased soil moisture deficit is likely during summer months (Hulme et al., 2002) In winter months the opposite may be true – leading to an increased risk of flooding Source: UKCIP02 Climate Change Scenarios

2. Climate Variable: Precipitation Poplar & willow are C3 crops and are highly dependant on water availability to attain maximum yield (Aylott et al., 2008) Souch & Stephens (1998) showed that poplar genotypes in severe drought conditions produced 60-75% less dry matter than those in the well-watered conditions Genotypic sensitivity to water is variable and genomics can help us identify the traits associated with drought resistance (e.g. stomatal closure), which can then be bred into future crops

3. Process model Process-based models allow linkages between climate change scenarios and productivity to be investigated The forest productivity model, ForestGrowth (Evans et al., 2004; Deckmyn et al., 2004), has been parameterised for use with SRC using literature and field measurements (Casella & Sinoquet, 2003; Gielen et al., 2003 etc.) and outputs have been validated against site/species-specific data (Aylott et al., unpublished data) Introduction

Phase 2: Leaves are then added and if there is insufficient light, stem growth will occur Phase 1: Storage carbon replenishes the existing canopy for 20 days Phase 3: Carbon will be added to the pool of stored carbon – in preparation for the following years growth Phase 4: Leaf fall occurs Phase 5: Dormancy 3. Process model ForestGrowth

3. Process model ForestGrowth has been parameterised for two species of poplar and two willow (see right for map of Populus trichocarpa genotype ‘trichobel’, second rotation) Yield differences in species and genotypes are driven by three input variables: – LAD per 25cm layer – Date of bud burst – Height area growth relationship ForestGrowth Outputs

ForestGrowth is currently being tested using arbitrary increases in CO 2, temperature and precipitation (based on UKCIP medium emission scenario) without irrigation or fertiliser In the future, ForestGrowth will be run using weather data generated by the UKCIP02 climate change scenarios (developed by the Tyndall and Hadley Centres) – This will allow us to account for other variables, including radiation and seasonal temperature/precipitation variation, in addition to different UK emission scenarios for the 2020’s, 2050’s and 2080’s 3. Process model Climate variable Scenarios

Atmospheric CO 2 increase from 370 to 550 ppm (P. trichocarpa) – On average yields increased by 29% but in Southern England and Northern Scotland yields were increased by up to 50%, due to stimulated photosynthesis – These figures are similar to field observations recorded by Calfapietra et al. (2003), who found an increase of up to 27% in poplar yields (550ppm) 3. Process model Results: CO2

3. Process model Summer temp. increase of 2.5 o C + rest of year increase of 0.5 o C (P. trichocarpa) – Yield at Alice Holt site (clay loam soil) is increased by 0.5 odt/ha/yr (+4%) by the end of the second rotation – increased respiration Results: Temperature

3. Process model Precipitation decreased by 10% (P. trichocarpa) – Yield at Alice Holt site (clay loam soil) is decreased by 1.3 odt/ha/yr (-12%) by the end of the second rotation – due to increased soil moisture deficit Results: Precipitation

3. Process model CO2 x temperature x water (P. trichocarpa) – Yield at the Alice Holt site (clay loam soil) is increased by 2.1 odt/ha/yr (+19%) by the end of the second rotation Results: 2050 Climate Scenario

3. Process model C3 bioenergy crop yields could increase by up to 20% in a future temperate UK landscape – however, as plants acclimate to new climates so too will pests and disease, potentially counteracting these effects These results should be linked to future plant breeding, even GM to ensure bioenergy crops for the future Extend to hotter drier climates across Europe Conclusions

4. Theme interaction There is ongoing collaboration within Theme 2.3 & 2.4: GHG balance of energy crops with Aberdeen – paper under construction Modelling supply chain scenarios with Imperial College – paper under construction Possible interaction with Theme 4: Providing clear and concise yield information

5. Publications TSEC AYLOTT M.J., CASELLA E. & TAYLOR G. Current trends in global bioenergy crop yields. In prep. AYLOTT M.J., CASELLA E., TUBBY I., STREET N. R., SMITH P. & TAYLOR G. (2008) Yield and spatial supply of bioenergy poplar and willow short-rotation coppice in the UK. New Phytologist, 178, BAUEN A.W., RICHTER G.M., DUNNETT A.J., CASELLA E., TAYLOR G., AYLOTT M. Modelling demand and supply of bioenergy from short rotation coppice and Miscanthus in the UK. In prep. CASELLA E., DREYER E., VANDAME M., CEULEMANS R., AYLOTT M.J., TAYLOR G. & SINOQUET H. (2008) Seasonal changes in temperature response of photosynthetic model parameters in relation to leaf nitrogen content for poplar. In submission with Tree Physiology. FARRELL K., AYLOTT M.J., CASELLA E. & TAYLOR G. Limits to the possible production and distribution to short rotation coppice in the UK? In prep. HILLIER J., RICHTER G.M., AYLOTT M.J., CASELLA E., TAYLOR G. & SMITH P. GHG emissions from bioenergy crops. In prep. Non TSEC CASELLA E. & SINOQUET H. (2003) A method for describing the canopy architecture of coppice poplar with allometric relationships. Tree Physiology, 23: DECKMYN G., EVANS S.P. & RANDLE T.J. (2004). Refined pipe theory for mechanistic modelling of wood development. Tree Physiology, 26:703–717. EVANS S.P., RANDLE T., HENSHALL P., ARCANGELI C., PELLENQ J., LAFONT S. & VIALS C. (2004). Recent advances in mechanistic modelling of forest stands and catchments, Forest Research Annual Report

6. Acknowledgements We thank Forest Research for the ForestGrowth model and site data. This research was funded by NERC, as part of the Towards a Sustainable Energy Economy initiative ( and through a PhD studentship to Matthew Aylott. Gail Taylor was supported by UKERC as part of the ‘Future sources of energy’ theme.