I have not read many alternatives but my favourite account of such an event is H G Wells’ War of the worlds. The aliens arrived with hostile intent and aggressive hardware, only to be killed off by infectious diseases – in fact I think it was the common cold! So yes: I think I would want to be un-discovered and I think the Amazon tribes would like to be undiscovered. Except that as soon as they see our cotton clothes and less-useful inventions, they want to have them. Also there are likely to be queues of ‘charity workers’ wanting to deal with their medical problems.

However, I am wondering if some ‘advanced’ civilization existed in space whether we would really be happy to be contacted? In what circumstances would this be good? In what circumstances might it have all the negative impacts that are sometimes portrayed in science fi movies? Perhaps some ethical scenarios might help us work out what we would like to happen if we were the ‘undiscovered’ ones?

Tragically, the ‘undiscovered’ tribes of South America are still be devastated by infectious diseases http://www.livescience.com/14772-uncontacted-tribe-brazil.html . Taking the discussion to Canon Bernard Iddings Bell, I wonder if he would see this as a failure of modernism (ie its reluctance to base the action of ‘protecting the indigenous peoples’ on belief and tradition. I think he might see it this way but I do not know if he would advocate a pre-modern remedy (isolation) or a post-modern remedy (antibiotics, I suppose). I’d go for pre-modernism and leave them alone for ever and ever.

Possibly with increased medical understanding ideas of immunity, disease resistance, disease origin, communicability, localised treatments including diet and socio-cultural behavoural adaptations and other aspects of disease profiles will be less mysterious?

One theory is that syphilis http://en.wikipedia.org/wiki/History_of_syphilis came from the New World. Another theory is that diseases tend to be worse in cities and therefore resistance to disease becomes stronger in cities than in rural areas, so there was less resistance in South America.

Yes re both oak and ash. I do not think the tree problems are caused by climate change. They are more likely to result from a lack of bio-security for wood products, rather as the conquistadores decimated the population of South America by unwittingly transporting European diseases to the ‘new world’.

Holting the spread of chalara seems to be partly a quarantine issue, and possibly much of the reasoning behind the need to license tree felling. (and at this point the anthro centric and eco centric aspects overlap).

Do you know whether changing climatic conditions are making the trees more vulnerable, including incidence, timing and frequency of winds which spread spores?

I guess the ‘Hearts of Oak’ are considered but of England’s all-too-mutable heritage. Most of the oak sold in the UK now comes from France, which has had an excellent policy for managing oakwoods since the time of Louis XIV. England cut down its oak woods to make ships. The elm trees were lost to Dutch elm disease about 30 years ago and the ash trees will soon be lost to Chalara.

What is the thought process behind the licencing of felling oak trees in the UK? Is it anthro or eco centric?