Why is clear urging an especially damaging forestry practice for species that rely upon older trees for their survival

How old, is the tree, and does this represent any kind of graph?

'Genetics in Swedish forestry practice' - - subject (s) : Afforestation, Forests and forestry, Genetics

'Den oligarchs astringency och partaken' - - subject (s) : Afforestation, Forests and forestry, Genetics, Trees