Not all plant species are affected by pollution. In France, for example, three laboratories of the organization Inra (bioclimatology of Bordeaux, forest ecology of Nancy and plant ecology of Orsay) have seen how the trunk of trees of temperate regions has become very thickened.
Dendrochronological measurements indicate that since 1850 pedunculated oak increases 55% in Lorraine and 160% pine in Vosges. This is mainly due to higher CO2 content in the atmosphere. Nitrogen oxide, nitrates, ammonia and other pollutants also have to do with climate change (climate warming and increased precipitation) for proper forest management.