Change in the dendrochemistry of sacred fir close to Mexico City over the past 100 years

abies abies religiosa air pollution bark bois bois de coeur cadmio cadmium chemistry chimie cinc contamination corteza dendrochronologie dendrochronology dendrocronologia duramen heartwood lead madera oligoelementos ph del suelo ph du sol plomb plomo pollution du sol soil ph soil pollution trace elements urban areas urbanisation urbanization wood zinc zonas urbanas zone urbaine