these are by far the largest birch i have seen in this area. Betula pendula i think.
here is an interesting item relating to birch pollen allergy
http://www.foodsmatter.com/allergy_intolerance/miscellaneous/articles/allergies_across_europe.html
"The north/south divide
However the most interesting finding so far is the strange north-south divide which runs across southern France, through Italy just north of Florence and on eastwards to the Black Sea.North of this line people react to the flesh of apples, south of the line, to the skin. The answer to this conundrum may lie, yet again, with the birch tree as this line also marks the latitude south of which the birch does not grow.
The birch connection – again...
Apples contain two major allergenic proteins, Mal d 1, which is found in the flesh, and Mal d 3, which is found in the skin. Mal d 1 closely resembles the allergenic protein Bet v 1, found in birch pollen.So, anyone who is already allergic to Bet v 1, is ‘primed’ to react to Mal d 1 – explaining why people living in birch growing areas and sensitised to birch pollen may also react to apple flesh.
South of the birch growing area, the apple protein Mal d 3 is closely related to Pru p 3, the main allergenic protein in peaches. And, as the EuroPrevall study has already noted, the prevalence of peach allergy is highest in the Mediterranean area.
Interestingly, Mal d 1 breaks down when heated, where as Mal d 3 does not – which could explain why apple-allergic northern Europeans are fine with cooked apple or pasteurised apple juice, but southern Europeans cannot tolerate apple in any form.
The question of why those who are birch sensitised should react to apple flesh, but those who are apple sensitive do not necessarily react to birch pollen has also baffled researchers. They believe that this may be because the Bet v 1 from birch pollen enters the body via the lungs rather than the digestion. It can therefore reach the bloodstream intact. Had it been eaten, it would have been broken down by stomach acids etc and would have lost the ability to sensitise the immune system. But once the immune system is sensitised by Bet v1 it is likely to react to any similar looking proteins such as Mal d 1."