This dataset presents herbivory damage assessed on 1982 mature focal trees sampled on exploratory sites. Overall, each tree has got 7 variables measured on crown and 2 variables measured on a leaf sample. Those 2 variables are a synthesis of 6 different insect guilds (chewers, skeletonisers, miners, tiers, rollers and gallers). Some trees have only information on crown assessment or leaves assessment.

Focal trees were selected at random as follow. Three individuals per species per plot in mixture among the 6 biggest DBH and 6 trees in monocultures among the 12 biggest DBH. Some plots have more trees sampled. Crown assessment protocol : pourcentage of crown light and shade were distinguished. For each part, observer evaluated proportion of dead branches, anormal decoloration of leaves (not shown in this dataset) and defoliation. Binocular were used for observation. Leaves assessment protocol : 30 leaves were collected at the top and bottom of crown (60 leaves per tree in total). For each leaf, observer evaluate area damaged by chewers and skeletonisers (ectophagous insects). Leaf miners, tiers, rollers and gallers evaluated by presence/absence (endophagous insects).

Exploratory sites from Italy, Germany, Finland, Spain, Romania, Poland

Crown assessments and leaf sampling (frozen after collect) were done on the field at following dates. Italy : from 12/06/2012 to 02/07/2012, Germany : from 09/07/2012 to 18/07/2012, Finland : from 06/08/2012 to 15/08/2012, Spain : from 08/06/2013 to 21/06/13, Romania : from 08/07/2013 to 17/07/2013, Poland : from 29/07/2013 to 09/08/2013

Focal tree species are : Abies alba, Acer pseudoplatanus, Betula pendula, Carpinus betulus, Castanea sativa, Fagus sylvatica, Fraxinus excelsior, Ostrya carpinifolia, Picea abies, Pinus nigra, Pinus sylvestris, Quercus cerris, Quercus faginea, Quercus ilex, Quercus petraea, Quercus robur, Quercus rubra Insect guilds are : chewers, skeletonisers, miners, tiers, rollers and gallers. Some galler species were identified. In case of need, ask to author to know them.

Some insects damage are to small to see them during the crown assessment. In general, observer can assess chewer damage and some big galler species with binocular. On conifers (Pinus sp.), it was possible to see egg laying of scale insects on needles.

Data from crown assessment are Phyto_cl, Phyto_cd, Color_cl, Color_cd, DeadBR_TOT_CL, DBr_Phy_TOT and Crown_dam_tot. Data from leaves assessement are Prop_endophag and Prop_area_ectophag. Shoots assessment informations on conifers are missing (no significant damage observed by crown assessment). IMPORTANT COMMENT : It's possible to sum "Phyto_cl" and "Phyto_cd" or "Color_cl" and "Color_cd" to obtain total herbivores damage or anormal coloration on crown. These are the only possible calculations. But, for example, you can not sum "Phyto_cl", "Color_cl" or "DeadBR_TOT_CL" to obtain total damage on crown light. Calculation will be false. Focal trees were also sampled for pathogens damage assessment, Carbon and Nitrogen element analyses, stable isotope composition, and chlorophyll fluorescence. Dead branches can be a long term consequence of insect attacks (e. g. on Castanea sativa).