Variables : Biomass calculation

Analysis and modelling of the basic wood density variability of French forest species Baptiste Kerfriden, PhD student 2017-2020 Supervisors : Jean-Michel Leban, Jean-Daniel Bontemps

Context • French Research and Innovation plan (PRI) 2025 : improve the Forest and wood sector’s performance, increase the use of wood in a perspective of bioeconomy, adapt forests and prepare the future forest resources, and improve the tools and methods to evaluate and predict the evolution of the forest resources at different scales from multiples sources of information • The need to report the wood density variability : intra and interspecific, by stand type, under geographic and climatic gradients for all of the French forests described by the National Forest Inventory, for biomass estimation (Weiskittel 2015, Chave et al. 2004) • French National Forest and Wood Program 2016-2026 : increase wood harvest by 12 millions of cubic meter Global issue How to assess and plan in the long term, detailed and accurate, the estimates for biomass and carbon stored in the French forest ? (Action C.3-2 of the PRI) Questions • What are the main effects and interactions of controlled factors (species, management, geographic localisation) on the wood density variation ? • Can we identify regional patterns between wood density, growth and age variation ? • Can we predict the rate of biomass production at the national scale with NFI variables ? • What are the relationships between basic wood density and tree growth at an inter-specific level ? (Woodall 2015) Materiel and methods • The wood increment cores collected by the NFI staffs (SIFE, IGN) : more than 54 000 cores for 2016-2017 • Basic wood density measurement by using the XDM method (Leban 2016) : use of boxes, x-rays scanner and CarDen software (Jacquin 2017) • The descriptive variables of the sampled plots by the forest inventory Botanical Dendrometric Geographic

Variables :

Biomass calculation : Increment cores in a box

Species, plot main species, plot composition, stand type, flora, soil Dbh, height, age, slenderness (H/Dbh), Dbh/Dg (social status), ring width Coordinates, altitude, property (private, public), major ecological regions (GRECO) Actual results of NFI Aboveground volume of trees x New measures XDM Wood basic density = New results for NFI Biomass

Results obtained during the first year Measurements in progress Database of basic wood density for 2016-2017 complete with the trees and forest stand variables Example of results obtained (preliminary data for illustration) : • Wood density variability for Quercus robur and Picea abies at the national scale : comparison between old and young • France map with the arithmetical mean of basic wood density for each plot (10 200) of the 2016 and 2017 NFI campaigns Work plan for the second and third year Analysis of basic wood density variability in relation with the others NFI measurements (dendrometric, botanical, geographic…) Modelling basic wood density by species to : • Assess the French biomass stocks and their annual increase in order to optimize their use • Study the trade-off for C allocation pattern between density and growth (Woodall 2015)

latitude

Basic wood density

Basic wood density (kg/m3)

longitude

This thesis is a part of the XDM project : Leban JM1, Hervé JC† 2, Bontemps JD2, Wurpillot S.4, Dauffy V.4, Morneau F.4,Touzet T.4, Jacquin P.3, Longuetaud F.3, Mothe F.3, Kerfriden B.1,2, Billard A.3, Savagner L.1,Trouy MC5, Douzain N.6 and all the engineers and the technicians of the National Forest Inventory and the Xylosciences platform of INRA Doctoral school : 1 - BEF, INRA / 2 - LIF, IGN / 3 - SILVA, INRA / 4 - SIFE, IGN / 5 - ENSTIB / 6 – FNB References • Chave, J., Condit, R., Aguilar, S., Hernandez, A., Lao, S., & Perez, R. (2004). Error propagation and scaling for tropical forest biomass estimates. Philosophical Transactions of the Royal Society B: Biological Sciences, 359(1443), 409-420. • Jacquin, P., Longuetaud, F., Leban, J. M., Mothe, F. (2017). X-ray microdensitometry of wood : A review of existing principles and devices. Dendrochronologia, 42, 42-50. • Leban, J. M., Hervé, J. C., Bontemps, J. D., Longuetaud, F., Mothe, F., Jacquin, P. (2016). Measurement of the annual biomass increment of the French forests – XYLODENSMAP project. In: IUFRO Working Parties 5.01.04 and 3.02.04 (WoodQc), 12–17 June 2016, Québec/Baie-St-Paul, Canada. • Weiskittel, A. R., MacFarlane, D. W., Radtke, P. J., Affleck, D. L., Temesgen, H., Woodall, C. W., ... & Coulston, J. W. (2015). A call to improve methods for estimating tree biomass for regional and national assessments. Journal of Forestry, 113(4), 414-424. • Woodall, C. W., Russell, M. B., Walters, B. F., D’Amato, A. W., Zhu, K., & Saatchi, S. S. (2015). Forest production dynamics along a wood density spectrum in eastern US forests. Trees, 29(1), 299-310.