I posted the picture above of an avenue in London earlier this year during the spring and in a natural navigation puzzle posed the question which way is it facing, and why?
It is actually facing west, that can be deduced from the fact that the leaves on the trees on the left have come out more than those on the trees to right. Hence those trees on the left must receive more sun and be southerly compared to the right which is more northerly and therefore shaded.
And now it is autumn the same technques can be used again in the picture below of the same avenue.
It can be seen that the trees on the left (i.e. south) are browner than the ones to the right (i.e. north). You can therefore use the relative time in which the leaves of trees go brown as an indicator of north / south direction.
This signal is only available at certain times of year, which means its not the greatest source of navigational information. And of course now we can get iPhones that have not just GPS but also a compass built in (alas my contract means I can't upgrade to it this year).
But putting it the other way round, because we know navigational information we can learn something about trees, such as that being south doesn't make the tree's summer much longer if at all (as it would have been if the first tree to show its leaves was also last to shed them) but roughly the same length as those trees to the north.
To our ancestors no doubt this would be a duh! moment, where they can't believe we need to have this pointed out. But for the urban dwelling technology user a lot of connection to these cycles of nature have been lost.
And yet we are human, and appreciate, value and to a degree need nature around us. London would certainly be the poorer if we didn't have the many green spaces to relax in.