In Britain today the average number of different tree species found in recently planted woodland is fewer than 10 (it is even less in ancient and native woodlands), therefore the chances of some new disease or insect predator causing devastation in that woodland is one in 10. In the Amazonian rainforest the average number of different tree species to each acre is about 100 (in some instances it can rise to 180), so the ratio of potential damage lessens to one in 100.
I am not suggesting we should plant upwards of 100 different species in our gardens or woodlands (although it might be great fun to try). I simply propose that we begin to widen the pool of species from which we choose.
Some conservationists will feel uncomfortable with this approach, preferring to only plant “native” tree species. The problem with this is that we limit ourselves to around 34 species (plus a few more subspecies) and potentially half of these are already susceptible to