OPTMix (Oak Pine Tree Mixture): an experimental site in temperate forest


OPTMix (Oak Pine Tree Mixture) is an experimental network of 33 instrumented plots in the state forest of Orléans over a total area of ​​40 ha. OPTMix allow to study cross factors : stand composition, stand density, with-without herbivores. Each plots covers an area of ​​0.5 ha where all trees have been mapped, and is surrounded by a buffer zone 20 meters wide. Most of the plots are equipped with microclimate sensors (measurement of temperature, relative humidity, radiation, rain, soil moisture at 3 depths, water table using piezometers). Dendrometers have been installed on a sample of trees in order to monitor their growth continuously and in particular on an intra-annual scale. At the same time, monitoring of populations of herbivores (wild ungulates and micromammals), diversity, vegetation dynamics and forest regeneration, and the use of resources by trees (water, light, nutrients) are carried out. The combined factors studied is rarely done at once and on the same forest and makes this site unique. Our objectives is to study the effects of the stand composition (pure sessile oak, pure Scots pine, mixed pine-oak), the stand density (number of trees/ha), and the presence of wild ungulates (roe deer, wild boar, red deer), on the ecosystem functioning such as tree productivity, resource use and allocation (including water and nutrients), biodiversity and understory vegetation dynamics including regeneration. OPTMix aims to improve knowledge on the functioning of mixed forests in temperate regions with direct applications to forest management, especially in the context of climate change.

(*) screenshots from the Oakpine1 simulator under the Capsis4 simulation platform

For more details see here.

OPTMix in a glance here.


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Project leader: Nathalie Korboulewsky (INRAE, UR EFNO Nogent-sur-Vernisson)

Participants from INRAE:

Set up and management of the experiment: Couteau Camille, Pérot Thomas, Perret Sandrine*

Phenology, growth and productivity: Couteau Camille, Pérot Thomas*, Perret Sandrine

Resources use: Balandier Philippe*, Couteau Camille, Korboulewsky Nathalie*

Forest dynamics: Boscardin Yves, Hamard Jean-Pierre, Mårell Anders*, Rocquencourt Agnès

Biodiversity: Dumas Yann, Gosselin Marion, Mårell Anders*

* Leader(s) of the research topic


OPTMix team

OPTMix team










The partners for the settlement of the site were INRAE (supervisor), the district Centre-Val de Loire, the french National Forest Office (ONF) and the General Council of Loiret. Funding for the measures and for running the equipments are provided by Irstea and scientific projects.  

Associated networks

OPTMix has integrated several scientific networks: – GIS COOP, Heterogeneous Forest Group since 2015; – SOERE F-ORE-T since 2016; – AnaEE France since 2017. In addition, OPMix is a candidate to integrate AnaEE Europe (European network under construction).


OPTMix was installed and equipped thanks to funding from the district Centre France, INRAE, and thanks to the Office National des Forêts who provided the stands. Funding for the measures and for running the equipments are provided by Irstea and scientific projects (more details here). Since 2017, OPTMix receives financial support from Ecofor as a member of …

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Application forms for a new experiment

You will find below the application forms if you want to perform a new experiment using the OPTMix device. To help you in this process please contact Nathalie Korboulewsky For researchers outside the INRAE-EFNO research unit at Nogent-sur-Vernisson: Click here to download the EXTERNAL application form (french version) For researchers of the INRAE-EFNO research unit at …

Data usage conditions and agreement, data request form and experimentation request form

You will find below the data usage conditions and agreement forms if you want to use data coming from the OPTMix device. This document also include a data request form and experimentation request form. To help you in this process, please contact Nathalie Korboulewsky. Click here to download the data usage conditions and agreement forms …