Working Groups


When the LEMONTREE project began, it was initially organised into 4 challenge areas which the group aimed to address:

Challenge 1 – Optimality at the leaf and plant levels

Challenge 2 – Biophysical coupling of atmosphere, water and land

Challenge 3 – Ecosystem properties and biogeochemical cycling

Challenge 4 – From plant function, biophysics and biogeochemistry to land-surface and climate modelling

For more information on these challenges please see the Challenges – Implementation page.

As a part of the Virtual Earth Systems Research Institute (VESRI) it is essential to work transdisciplinary and cross-institutionally to address some of the crucial scientific challenges needed to achieve advanced climate modelling capabilities. At the mid-term review in year three the project was restructured into seven teams which cut across the original LEMONTREE challenges, but also across institutions, to facilitate greater collaboration and cutting-edge science.

The seven new working groups aim to enhance the impact and relevance of the LEMONTREE project and will be led by one PI and one early career researcher. This will also further the career development of our ECR’s by providing them with leadership opportunities.


Working Group 1: C,N and P Cycles Synthesis

This working group aims to re-assess the way in which N, P and C cycling are currently modelled. A particular focus of the group will be assessing the way phosphorus data is implemented in current models as well as distinguishing between the land carbon sink trends in different models. The group is being led by Professor Beni Stocker (University of Bern) and Jan Lankhorst (Utrecht University).

This work shown below is an example of some modelling done by the group on global biomass in an attempt to understand aspects of the C and N cycles. It provided insights into nitrogen use efficiency globally and generated benchmarks for models that incorporate coupled C-N cycles.

Figure 1: Global simulations of biomass production (BP, g C m−2 year−1), above‐ground biomass production (ABP; g C m−2 year−1), leaf carbon‐to‐nitrogen ratio (leaf C:N), nitrogen resorption efficiency (NRE), N uptake (g N m−2 year−1) and nitrogen use efficiency (NUE, the ratio of BP to N uptake). The value at the top of each panel is a global estimate. Figure taken from Peng et al. (2023, Figure 3).

See the paper below for the full text:

Peng, Y., Prentice, I.C., Bloomfield, K.J., Campioli, M., Guo, Z., Sun, Y., Tian, Di, Wang, X., Vicca, S., & Stocker, B. D. (2023). Global terrestrial nitrogen uptake and nitrogen use efficiency. Journal of Ecology, 111, 2676–2693.

Working Group 2:  Leaf Area Dynamics and Carbon Allocation

Working Group 2 aims to build on the previous work of the phenology working group to develop a scheme to represent the seasonal dynamics of leaf area based on a universal optimality principle and to account for the effects of different resource availabilities on the fractional allocation of fixed carbon to leaves, stems and roots. The work on leaf area is well underway and the focus of the group is now moving to understanding differences between above and below group carbon allocation. The group is being led by Professor Colin Prentice (Imperial College London) and Wenjia (Shirley) Cai (Imperial College London).

Working Group 3: Canopy Temperature Working Group

This working group is developing a robust, tested way of modelling canopy temperature and its impact on evapotranspiration and photosynthesis. This will be done by investigating differences between air and canopy temperature and the controls of canopy temperature. In addition, the group will explore how reliable the land surface models are at simulating canopy temperature and whether they can be improved. The group is being led by Professor Pierre Gentine (Columbia University) and Dr. Bart Majcher (University of Reading).

Working Group 4: Fire-Vegetation Interactions

The Fire-Vegetation interactions working group is aiming to develop a new fire model using eco-evolutionary optimality principles of fire and vegetation interactions to design a new fire regime framework that can simulate different aspects of the fire regime.  Firstly, the group aims to understand which plant traits, if any, can be used to improve predictions of burnt area, fire size and fire intensity. Secondly, the group will incorporate these traits into our current working model of fire to better predict elements of the fire regime. The model will then be coupled to the P model to better improve climate predictions. The group is being led by Professor Sandy Harrison (University of Reading) and Dr. Olivia Haas (University of Reading).

The below figure is taken from some work done prior to the establishment of the group that aims to model global wildfire regimes using a number of input variables. This model forms the basis of the working group model which we aim to continue to build on to improve predictive power.

Figure 2: Observed (left) and predicted (right) annual BA (fraction), monthly median FS (km2) and monthly median FI (W km−1). Taken from Haas et al. (2022, Figure 3).

See our blog post on this work here for more detail or view the citation below for the full text:

Haas, O., Harrison, S.P. and Prentice, I.C. 2022. Global environmental controls on wildfire burnt area, size, and intensity. Environmental Research Letters.17 e065004

Working Group 5: Ecohydrology

The Ecohydrology working group aims to address linkages between vegetation and water at the ecosystem level with an eco-evolutionary optimality framework. They are exploring links between water and plants at the ecosystem level and exploring ways to model the temporal behaviour of the water-plant continuum in response to prolonged drought. This has begun with an exploration of the factors contributing to variation in potential evapotranspiration products. The group is being led by Professor Xu Liang (University of Pittsburgh) and Amin Hassan (University of Pittsburgh).

Working Group 6: Vegetation Dynamics/Functional Diversity

This working group is providing a basis for representing functional diversity and its role in ecosystem function and dynamics. A key aspect of this work is to characterise leaf and hydraulic trait variability and to understand how these traits impact vegetation dynamics. The group is using both fieldwork, to understand how traits are related to environmental variables, and modelling, to see if observed relationships can improve representations in land surface models. The group is being led by Associate Professor Han Wang (Tsinghua University) and Huiying Xu (Tsinghua University). Check out our blog post on the fieldwork behind some of the work being done in this group here.

Work being done in the field for the analysis in Hainan, China.

Working Group 7: Implementation Working Group

The implementation group will officially begin in August 2024 after the LEMONTREE annual meeting. This group will aim to implement components of the P++ model in hydrological and land surface model frameworks to demonstrate feasibility of using the full P++ model to improve current predictions. The initial focus will be on acclimation of GPP, prediction of fAPAR/LAI, and, incorporation of soil moisture stress. This group is being led by Professor Pier Luigi Vidale (University of Reading).

The working groups will run from mid-year 3 to the end of the 5-year project. Working groups 1-6 will aim to wrap up science around the end of Year 4, and Year 5 will focus on the implementation of the science into land surface models.

Working across the seven working groups will allows us to address the initial four challenges that LEMONTREE set out to address whilst facilitating greater collaboration and innovative science. Ultimately, the group aims to generate a next-generation land surface model that can improve current climate predictions. Achieving our science goals by developing the novel science outlined above will be crucial in producing this new model.