This is a photo of a monkey puzzle tree that I have been growing in our greenhouse since early this year. I have taken it out of the greenhouse for better light for this photo. Greenhouses are great places to study the effect of sunlight on plant growth because all the wind effects are cancelled.

Now see if you can tell in which direction this photo was taken. Are we looking north, south, east or west?

Answer time…

In this photo we are looking west. The monkey puzzle tree has grown towards the southern light to the left, an effect known as ‘phototropism’.

‘That’s easy!’ I hear some of you cry, but I did warn you that this was a test of your powers of observation. What I did not tell you is there were two marks on offer.

Now be honest, did you spot the way there is more moss growing on the southern side of the soil too? The sunlight cannot reach the left, southern side of the soil because it is being blocked by the rim of the flowerpot. (Those of you already familiar with natural navigation will be aware that this is the same shading effect that leads to more puddles on the southern side of east-west tracks).

And no, before you ask, there is no bonus point for spotting that the chicken is aligned east-west in the background.

The plant is dramatically heavier on its southern side and it is also displaying the ‘Tick Effect’ across its stems – more vertical growth on the northern side, more horizontal on the southern.

Here I am taking a break from family duties and checking that the snow is doing what I have come to expect of it. The compass feels very light after hours of hauling a tobogganing sled, weighed down by two lumps, up the hill repeatedly.

Some man-made structures can give us a clue to help us on our way until nature comes to our aid again. Churches are a good example. A lot of churches are aligned East-West and this can offer a short term hand if all else is proving confusing, not unusual in a built-up area. The problem with a lot of artificial clues like this though is that they are very short-lived, they offer a clue for a few seconds or minutes at best, but then disappear out of sight and leave the navigator on their own again. Airports, with a little lateral and logical thinking, go one better than this…

Most people know that runways have their headings printed in big white numerals at either end. 02/20 runway runs roughly NNE/SSW. Pilots and plenty of others are also aware that this is because the aircraft that use them must take off and land into wind and so runways are usually aligned into the prevalent wind. There are a lot of W/E and SW/NE runways in Britain.

It is only a short leap from there, but one that few make, to realise that the trees in the area are very likely to reflect this prevailing wind direction in their own shape. More importantly they are likely to do it well beyond the visual range of the runway itself. Next time you look at a runway it’s worth remembering that it might be offering you a finely tuned natural compass for the local area.