Towards comprehensive maps of tree structure and function: linking tree architecture, anatomy and physiology

Informations projet

treeMAAP

N° de convention de subvention: 897496

DOI

10.3030/897496

Projet clôturé

Date de signature de la CE 15 Avril 2020

Date de début 14 Avril 2021

Date de fin 13 Avril 2023

Financé au titre de

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Coût total

€ 184 707,84

Contribution de l’UE

€ 184 707,84

Coordonné par

INSTITUT DE RECHERCHE POUR LE DEVELOPPEMENT
France

Periodic Reporting for period 1 - treeMAAP (Towards comprehensive maps of tree structure and function: linking tree architecture, anatomy and physiology)

Période du rapport: 2021-04-14 au 2023-04-13

Résumé du contexte et des objectifs généraux du projet

There is a vast diversity of tree form and function – some of this diversity, like tree architecture, can be seen with a bare eye but other diversity, like wood anatomical structure, requires microscopes. The different levels of organizations should be coordinated based on the same principle building engineers apply to buildings: specific building materials are required for specific structure, for example, steel reinforced concrete allows to build tall buildings. TreeMAAP – tree Mapping Anatomy and Architecture Project – investigated how wood anatomical properties, whole shoot and whole tree properties are all coordinated (analogous to coordination between building materials and whole building properties). The core objective of treeMAAP was to assess how anatomy, stem and leaf properties, and tree architecture are coordinated or trade off with each other to achieve given functional outcome (focusing on water transport). The study encompassed 18 highly diverse angiosperm tree species growing in the wet tropical forest of French Guiana.
Coordination between anatomy, whole-organ and whole-tree properties determines water and carbon fluxes and storage in trees and, ultimately, whole forests. So better understanding of this coordination is crucial for understanding of forest functions and forest response to current and future climate. Forests are fundamental to the survival of human societies, because we rely on forests to regulate climate and greenhouse gasses (e.g. the Amazon), because forests provide cultural value and improve human wellbeing, they host vast diversity of flora and fauna yet to be described and its benefits to humans yet to be explored.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

TreeMAAP tasks:
- Development of measurement protocols
- Reconnaissance trip to Cameroon
- Preparation of fieldwork in French Guiana
- Two-month fieldwork in French Guiana
- Post-processing of images, samples (anatomy) and raw field data
- The ER received training: shoot architecture, whole-tree architecture, terrestrial LIDAR, shoot age.
- The ER gave training: anatomical lab work and image analysis, Wacom tablet, conductive sapwood staining, shoot architecture
- Data analysis
- Two manuscripts write up
- Literature review on the functional significance of wood and bark anatomical components
- The ER lodged an application for collaboration with AI researchers (under “AI4Life” EU funded scheme) to apply AI tools to anatomical images
- Multiple informal discussions about treeMAAP and wood anatomy (with >30 researchers, students, technicians)
- Disseminated the results and background knowledge

TreeMAAP results:
1) Tree species which produce large terminal shoots (large stem diameter at 0.7 m from shoot tip), also had larger stem volume, dry mass, produced large total leaf area, larger vessels, and larger conductive wood area in comparison with small shoots. Large vessels in combination with large conductive wood area resulted in high whole-shoot water conductivity.
2) Total volume of living tissues was higher in large shoots. This was driven chiefly by shoot size, not by living tissue fraction (volume of living tissue per volume of wood).
3) Taller, sun-exposed species had less dominant principal axis (umbrella-like tree architecture, with no obvious dominant axis) than shorter, shade-tolerant species (fir-like tree architecture with strong dominant axis). These taller species also built larger shoots which were more efficient in water transport. Presumably, that higher conductivity met larger transpiration demands in taller, sun-exposed trees.
4) Tree architecture was not self-similar, that is, highly branched shoots were not necessarily borne on highly branched trees. Likely, whole tree architecture and crown metrics are highly dependent on the neighbourhood conditions (e.g. larger neighbouring tree strongly limit expansion and canopy shape of the other tree) and on tree history (e.g. loss of branch due to mechanical damage).
5) Species which produced larger terminal shoots also widened their vessel diameter (from shoot to trunk base) at a slower rate, meaning, that their total water transport resistance was higher (everything else being equal). This indicates that they might use other anatomical adjustments (e.g. larger vessel pits) to lower water transport resistance.
Conclusions: 1) there are no functional trade-offs at the whole-shoot level, rather, traits coordinate to achieve larger overall values, for example, larger shoots (at a given distance from shoot tip) were more highly conductive due to larger vessels and larger conductive area. 2) there is a coordination between whole-shoot functions and whole-tree architecture (e.g. taller, sun-exposed trees with umbrella-like architecture had more conductive shoots). 3) Trunk and shoot growth rates are missing link in our understanding of carbon and water fluxes. Their measurements—in concordance with anatomy, physiology and architecture—is the priority for future research.

Result exploitation and dissemination.
The background knowledge on functional wood anatomy, methods and results have been communicated with broad scientific and non-scientific community:
1) Two seminar talks at the host lab
2) Led group discussion about tree architecture based on recent literature
3) One seminar talk in French Guiana
4) Two posters and pitch talks at the European Conference of Tropical Ecology 2022
5) Poster presentation at INTECOL 2022
6) Festival of Science, two weekends in two locations in Montpellier
7) Seminar talk at Ecological and Forestry Applications Research Centre in Barcelona, Spain
8) Guest lecture at the Montpellier University
9) Data shared with other researchers to develop grant proposal and to analyse a different aspect of plant function (metabolic scaling theory)
10) A subset of results included in an invited review
11) Two publications are in preparation (see figure)

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

1) TreeMAAP rigorously quantified wood anatomy in relation to whole-shoot and whole-tree properties. Before this work, we only quantified anatomical variation out of the context of organ size (except plant height) and tree architectural variation without the knowledge of variation at the lower scale (shoots and anatomy). This work shows that anatomy is coordinated with whole-tree and whole-organ structure. This is the first step to better understand whole-tree functions. This is important because climate and evolution acts on whole individuals, not on little abstract pieces of wood. Future cutting-edge studies should include multiscale of organization.
2) TreeMAAP was the first study combining wood anatomy with shoot properties and tree architecture. The approach, specific protocols used and results provide a reference point for future studies.


Potential impacts: scientific community, socio-economic impact, wider societal implications.
1) Once the research is published, all data will be open via data repositories (TRY). This data can then be used for meta-analysis and vegetation models predicting responses to current and future climate. Potential users of the data include: modellers, plant ecologists, physiologists and anatomists. In addition, specific measurement protocols used in treeMAAP will be useful for colleagues who want to run similar measurements.
2) The ER will use treeMAAP results to develop a new research project which will extend treeMAAP scope to include growth rates.

treeMAAP - summary figure