fundiv france database

Study Extent

Valleys and hills of Gascony in South-West of France, on Lamothe and Aurignac study sites. Trees were recorded once, from spring to automn 2012.

Sampling

Wood selection: First, for each site, ordnance survey maps providing land uses from the early 19th century were digitized and georeferenced according to the method described by Dupouey et al. (2007). Then, current tree vegetation was extracted from BD TOPO© (IGN 2010) with GUIDOS free software. To obtain a sample of old fragmented forests, those two informations were crossed. Second, 20 woods on the 42 prospected were retained with criteria of size from 14 to 50 ha, potential of target trees in pure and mixed neighbourood and accessibility (Burnel et al. submitted). To avoid eventual edge effect inside, forests crossed by significant road, clearing, recent cutting, elongated in shape or too small (Alignier 2010) were eliminated. Edge limits were redrawn in case of recent cutting to the forest border. The ArcGIS software, 10.2 version (ESRI 2012), was used for all cartographic work. Tree selection: Each wood was visited to describe target trees (Quercus robur or petraea) and their neighbor trees. They were chosen at the edge (until 30 meters from the border) or in the forest interior (more than 60 meters from the border). For each target tree, coordinates and some measurements (height, DBH, health condition) were recorded. Neighbor trees were considerated as tree whose crown was at a maximum of 3 meters of crown of the target oak. Only neighbor trees with DBH up to 10 cm and/or taller than the half of average height of canopy were described to exclude too small individuals. Species, distance between neighbor stem and target stem, height and dominance status were noted.

Quality Control

leaves collected on a subsample of 141 target oaks allowed to identify Quercus pubescens.

Method steps

1. Sample of 100 leaves were collected per tree on a subsample of 141 taget oaks. Leaves were frozen at -18°C. Then, damage or abundance of 7 insect guilds were assessed. Crown defoliation was also evaluated in the fiels.

All species indexed are tree species: Gymnosperms: 2 Pinaceae species Angiosperms: 4 Betulaceae, 1 Fabaceae, 6 Fagaceae, 2 Malvaceae, 3 Oleaceae, 1 Rhamnaceae, 6 Rosaceae, 1 Salicaceae, 2 Sapindaceae, 1 Ulmaceae species. Distinctness between Sessile, Pubescens or Pedonculate oaks was impossible on the field.

1. Quercus sp.
   common name: Sessile, Pubescens or Pedonculate oaks rank: species
2. Carpinus betulus
   common name: Hornbeam rank: species
3. Prunus avium
   common name: Wild Cherry rank: species
4. Acer campestre
   common name: Field maple rank: species
5. Fraxinus excelsior
   common name: Ash rank: species

Study area is located in France, in South-West of Toulouse (Gascony hills).