Preprints
https://doi.org/10.5194/gmd-2021-59
https://doi.org/10.5194/gmd-2021-59

Submitted as: development and technical paper 12 Apr 2021

Submitted as: development and technical paper | 12 Apr 2021

Review status: this preprint is currently under review for the journal GMD.

Using terrestrial laser scanning to constrain forest ecosystem structure and functions in the Ecosystem Demography model (ED2.2)

Félicien Meunier1, Sruthi M. Krishna Moorthy1, Marc Peaucelle1, Kim Calders1, Louise Terryn1, Wim Verbruggen1, Chang Liu1, Ninni Saarinen2,3, Niall Origo4, Joanne Nightingale4, Mathias Disney5,6, Yadvinder Malhi7, and Hans Verbeeck1 Félicien Meunier et al.
  • 1Computational and Applied Vegetation Ecology, Department of Environment, Ghent University, Ghent, Belgium
  • 2Department of Forest Sciences, University of Helsinki, Ghent, Finland
  • 3School of Forest Sciences, University of Eastern Finland, Finland
  • 4NPL, Climate and Earth Observation (CEO) group, National Physical Laboratory, Teddington, UK
  • 5Department of Geography, UCL, Gower Street, London WC1E 6BT, UK
  • 6NERC, National Centre for Earth Observation (NCEO), UCL Geography, Gower Street, London, WC1E 6BT, UK
  • 7Environmental Change Institute, School of Geography and the Environement, University of Oxford, Oxford, UK

Abstract. Terrestrial Biosphere Modeling (TBM) is an invaluable approach for studying plant-atmosphere interactions at multiple spatial and temporal scales, as well as the global change impacts on ecosystems. Yet, TBM projections suffer from large uncertainties that limit their usefulness. A large part of this uncertainty arises from the empirical allometric (size-tomass) relationships that are used to represent forest structure in TBMs. Forest structure actually drives a large part of TBM uncertainty as it regulates key processes such as the transfer of carbon, energy, and water between the land and atmosphere, but remains challenging to measure and reliably represent. The poor representation of forest structure in TBMs results in models that are able to reproduce observed land fluxes, but which fail to realistically represent carbon pools, forest composition, and demography. Recent advances in Terrestrial Laser Scanning (TLS) techniques offer a huge opportunity to capture the three-dimensional structure of the ecosystem and transfer this information to TBMs in order to increase their accuracy. In this study, we quantified the impacts of integrating structural observations of individual trees (namely tree height, leaf area, woody biomass, and crown area) derived from TLS into the state-of-the-art Ecosystem Demography model (ED2.2) at a temperate forest site. We assessed the relative model sensitivity to initial conditions, allometric parameters, and canopy representation by changing them in turn from default configurations to site-specific, TLS-derived values. We show that forest demography and productivity as modelled by ED2.2 are sensitive to the imposed initial state, the model structural parameters, and the way canopy is represented. In particular, we show that: 1) the imposed openness of the canopy dramatically influenced the potential vegetation, the optimal ecosystem leaf area, and the vertical distribution of light in the forest, as simulated by ED2.2; 2) TLS-derived allometric parameters increased simulated leaf area index and aboveground biomass by 57 and 75 %, respectively; 3) the choice of model structure and allometric coefficient both significantly impacted the optimal set of parameters necessary to reproduce eddy covariance flux data.

Félicien Meunier et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2021-59', Anonymous Referee #1, 15 Apr 2021
    • AC1: 'Reply on RC1', Félicien Meunier, 06 Jul 2021
  • RC2: 'Comment on gmd-2021-59', Anonymous Referee #2, 04 May 2021
    • AC2: 'Reply on RC2', Félicien Meunier, 06 Jul 2021
  • CEC1: 'Comment on gmd-2021-59', Juan Antonio Añel, 17 May 2021
    • AC3: 'Reply on CEC1', Félicien Meunier, 06 Jul 2021

Félicien Meunier et al.

Félicien Meunier et al.

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Short summary
We integrated state of the art observations of the structure of the vegetation in a temperate forest to constrain a vegetation model that aims to reproduce in silico such ecosystem. We showed that the use of this information helps to constrain the model structure, its critical parameters, as well as its initial state. This research confirms the critical importance of the representation of the vegetation structure in vegetation models and proposes a method to overcome this challenge.