The snow has finally begun to thaw in this freezing microclimatic corner of West Sussex, but I did manage a fair amount of stomping around in the snow over the past week. This is a picture I took in my local beech woodland a couple of days ago.

Lichens are very sensitive to their environment – moisture levels and air quality in particular – but also the surface they grow on. This means that they can be used to understand direction, but a little local knowledge and familarity with the stones and barks of your area helps greatly.

There is a rust-coloured lichen that is clearly not keen on surfaces that dry regularly and can be found on the moist sides of many trees in southern England, not least beech trees.

It is a reasonably dependable indicator of north on trees that are open to at least some drying from sunlight.

(If there are any lichenologists out there that might be able to point me to the right page of the ‘Mosses and Liverworts of Britain and Ireland Field Guide’ for this particular friend I’d be very grateful.)

A similar principle can be used on land to find towns or villages. The number of roads, paths, power lines and communication cables increases as you get nearer a town; of course light and noise pollution also increase. There are some more ‘lateral’ clues too.

On the weekend I was walking with friends in the South Downs. My friend had the map and so I did not know exactly how far we were from our lunch stop, the George and Dragon pub in the West Sussex village of Burpham. We had been walking for about 9 miles, in deep snow and along slushy paths. We were hungry, which can help sharpen the senses.

I knew that we were within half a mile of the village when the incidences of dog mess sky-rocketed along the sides of our path. Dog-walkers are habitual and have their rituals. The path we were following into the village was clearly a favourite short walk for the dog-owning villagers. There were at least one hundred poops in the space of four hundred metres. Disgusting, yes, but in a strange way a welcome navigational sight. Lunch could not be more than 15 minutes away!

Gravestones tend also to be aligned east-west also, so that the dead are ready when ‘the trumpet shall sound and the dead shall be raised’. Any exposed stone that faces east or west will receive a mixture of sunlight and shade. Consequently they typically display a mixture of lichen types, as in the gravestone in this photo, in the graveyard of St Giles church in the quiet West Sussex village of Graffham.

On this gravestone there are a preponderance of gold and also grey lichens, with a smattering of darker lichens too. There was a very similar pattern on the other, western side, which came into the sunlight in the afternoon. The golden lichens are happy on stone that dries and are a reliable indicator that a face is receiving at least some sunlight. In other words you can find them on the south, east and west sides of masonry, but they are very rare on the northern side. In the unlikely event that this grave was aligned north-south then the southern side would be dominated by the golden lichens and the northern side would have a few grey and dark lichens and the telltale greens of mosses and algae.

The green wall in the photo below is a classic north-facing wall in the same churchyard, with no signs of gold, only a thin carpet of green moss.

The conditions were perfect, I could feel the summer heat rising up off the dust and sand and, had I been a snake myself, I would certainly have availed myself of the opportunity to do some serious basking. But sadly I met none and returned home without having dodged any venomous fangs, knowingly at least.

I did however come across a small stagnant pond that acted as a good compass. The water in its southwestern corner was clear, but in the northeastern end it was covered in a thick layer of dust, and fragments from broken twigs, leaves. The wind of the past week had marshalled all the particles floating on the surface into the leeward corner.

There are lots of places to explore on this website if you are looking for more information about the wonderful world of natural navigation, the courses that are available or my book on the subject.

It would be great to meet you so if you are within reach of west London tonight, I am giving a talk at The Travel Bookshop this evening (Thursday 17th) at 7pm. Details and tickets can be found on their website or by calling the bookshop on 0207 229 5260.

Hope you enjoy!

If you did not hear the Radio 4 Ramblings programme but would like to then you can by clicking here.

Details of some other natural navigation features on TV, Radio and in the press can be found here.

Where a canopy of dominant trees hogs the light, younger trees fight for their small share. This can often be seen, almost felt, in the shape of their branches.

Even in the late twentieth century many Bedouin are familiar with Polaris
(called al-Jidi) and Canopus (Suhayl), the two stars that indicate the directions
north and south. When a Bedouin, composing a poem, wanted to relate that
he was travelling south-east, for example, he said:
‘Ahutt al-Jidi ‘ald wirk il-matiyyah
W’adhrT naharhd ‘an Suhayl al-yimain’

‘I put Polaris on the thigh of my mount
While shielding her throat from Canopus south ‘.