In the framework of the “Young Scientist Contract” program (CJS, “Contrat Jeune 
Chercheur”) offered by INRA (French National Research Institute in Agronomy) in 
association with the Doctoral School “Ressources, Produits, Procédés et 
Environnement” (RP2E) of the “Université de Lorraine”, Nancy, France, 
the UMR “Forest Ecology and Ecophysiology” based in Nancy, France, is looking 
for candidates for a 

YOUNG SCIENTIST CONTRACT (5 YEARS) 
I.E. A PHD (3 YEARS) + A POST-DOC (2 YEARS) 

with the focus on : 

Competition for water between young planted trees and grass vegetation: 
Adaptation of management practices to climatic changes 

Background : Competition between species can positively or negatively impact 
growth and functioning of these species. Many studies on the influence of 
biodiversity on the functioning of grassland ecosystems (e.g. Loreau 2010) 
showed facilitation processes between species or differentiation of ecological 
niches, which can lead to an increase in productivity of the considered 
ecosystem. On the contrary, the presence of certain species in the ecosystem 
can cause the loss of other less competitive species. In forest plantations, 
competition for water and nutrients is a major interaction between the 
spontaneous herbaceous vegetation and young planted trees. It strongly 
influences the survival and early development of young trees (e.g. Nambiar and 
Sands 1993). 
The proposed thesis fits into this framework, where the interactions for the 
acquisition and use of water between planted Oak or Pine trees and the 
spontaneous herbaceous vegetation will be analyzed. 
Furthermore, different climate change scenarios foretell situations of 
competition for water and nutrients even more intense in the coming decades in 
France and Europe. However, no operational tool currently allows estimating the 
positive or negative effects of herbaceous vegetation on plantations in 
situations of increased moisture deficit or mineral deficiency. The development 
of a model taking into account these interactions and specific site 
characteristics would allow simulating the impact of these changes on the 
success of plantations and on future productivity. The development of such a 
model is complex and requires coupling two different approaches, the analysis 
of forest stand dynamics and characterization of plant functioning. This will 
be the main objective of the research program. 

Objectives: Specifically, we wish to address the following question: 

What is the influence of competition for water between woody seedlings and 
herbaceous vegetation on the carbon and water relations and growth of woody 
plants? 

The overall objective is to achieve a model of competition between young trees 
and neighbouring herbaceous vegetation in forest plantations, which would allow 
estimating the competition for water resources induced by the vegetation and 
the impact on productivity of the plantation, in contrasting water supply 
conditions. The development of such model requires (i) a fine characterization 
of ecophysiological processes of competition between vegetation and young trees 
and (ii) the study of their influence on carbon and water relations of plants 
and their growth. 
The detailed objectives of this project are (1): To quantify, in different 
moisture conditions, the distribution of resources, the distribution of the 
roots of plant and competing vegetation, the carbon and water relations of 
woody plants, and plant growth, and the relationships between them, (2) to 
estimate the intensity of root competition for water between herbaceous 
vegetation and young trees in different situations of water availability (field 
capacity, drought) in controlled conditions (nursery and “phenotyping robot”), 
(3): to propose a functional model of competition between woody plants and 
herbaceous competitors, based on the above components. 
The candidate will (i) perform a large set of ecophysiological measurements 
(growth, distribution of water and nutrients in the soil, leaf gas exchange, 
carbon and oxygen isotope composition ...) on the aboveground and belowground 
compartments of trees and neighbouring vegetation in plantations in France or 
in controlled conditions at INRA Nancy, and (ii) conceptualize and develop a 
functional model of growth of young planted trees. 
The proposed project will allow the young scientist to acquire a thorough 
knowledge of forest ecology and functional ecology, especially on forestry 
practices in temperate forests. He will participate in the design and 
parameterization of a functional model, in collaboration with French and 
foreign scientists involved in his PhD committee. The young scientist will 
acquire multidisciplinary skills in the areas of basic and finalized research 
that will allow him easily adapting to future offered research positions. 

Applicants should hold a Master of Science (M.Sc.) or equivalent degree (M2 in 
France) in a discipline relevant to one of the above specified projects (e.g. 
ecology, forestry, plant biology, environmental sciences). As the “Young 
Scientist Contract” program is highly selective, only the candidates with the 
highest Master level grades should apply and will be considered. The project 
requires a high level of autonomy and organization, and great interest in 
conceptualization and modelling. Extended working periods (1-2 weeks in a row) 
at field sites in various parts of France are planned. The applicants must 
demonstrate a strong interest in conducting interdisciplinary research. 

We are offering a 5-years fixed term contract, which includes a PhD period (3 
years) and a post-doc period (2 years). The program is part of a in an 
interdisciplinary research project at the cutting edge of biodiversity – 
ecosystem functioning research carried out in two scientifically excellent 
international teams. The candidate will be based at INRA Nancy, France, for the 
PhD and a 12-16 months period in a foreign laboratory is programmed during the 
post-doc period. Net salary will be around 1400 € per month during the PhD. 

For further information, please contact one of the following addresses and/or 
send your application including a cover letter, recent grades (M.Sc., or Master 
degree 1 and 2, or recent years of Engineering school), and detailed CV to: 

Damien BONAL, INRA Nancy, UMR EEF - Université Nancy / INRA, 54280 Champenoux - 
FRANCE; tel: +(33) 3 83 39 73 43; fax: +(33) 3 83 39 40 22; mail: 
[email protected]; website : http://www.nancy.inra.fr/eef 

AND Catherine COLLET, INRA Nancy, UMR LERFOB - AgroParisTech / INRA – 54280 
Champenoux – France: [email protected]; tel : +(33) 3 83 39 40 43; website : 
http://www.nancy.inra.fr/foret_bois_lerfob 

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Noël LE GOFF
Chargé de mission
Laboratoire d'Etudes des Ressources Forêt-Bois (LERFoB)
UMR INRA-ENGREF 1092
INRA-Nancy
54280 Champenoux - FRANCE
e-mail: [email protected]
tel: 03 83 39 40 39
fax: 03 83 39 40 34
http://www.nancy.inra.fr/foret_bois_lerfob
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