UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
Home
How it Works
Ask a Question
Search Topics
Webcasts
Our Scientists
Science Links
Contact Information
Can moss determine direction when you are lost?
Answer 1:

If you are lost, the best thing to do is to stay put. The more you move, the bigger the area people have to search to find you. Try to make yourself easy to see and hear. Stay calm and take care of yourself.

Here’s why people used to say that about moss and trees. Moss grows in cool, damp places. In the northern hemisphere (the US, Canada, Europe, Russia, China, etc.), the sun hits southern hillsides and sides of things more than it hits the northern sides of things. That’s because Earth tilts a little. In the summer, the sun looks high in the sky at noon. In the winter, it is still hanging low in the south, even at noon. The closer you are to the North Pole, the lower the sun will look in winter.

We call small differences in temperature and wetness “microclimates.” Micro means small. Climate is like a long-term view of weather. It means what a place is usually like, even though weather changes all the time. For example, you may live in a hot climate, but the place under a tree will be cooler and wetter than the places that have no shade. The tree makes a microclimate.

So if you looked at a bunch of trees in a forest that has moss mostly on one side of trees, the mossy side is probably north. But maybe that side is under the shade of a slope or something, while the north side is open to sunshine because of a road. Then the north side would have less moss. The north side MAY be more mossy. Or the whole tree may be mossy. Or the tree may have no moss at all. You can’t really count on the north side always being more mossy. So if you’re lost, stay where you are.

Look around your home or school. Can you find microclimates that are warmer or cooler, wetter or drier, or more or less windy?

If you are interested in how climate, soil, water, and air affect living things, you may want to study ecology.

Thanks for asking,

Answer 2:

Great question, this is an idea that many outdoor survival guides have dealt with for a very long time. Traditionally, it was thought that moss always grew on the north side of trees or rocks because during the middle part of the day the sun is shining from the south towards the north and therefore the north side of tress and rocks see a lot of shade, allowing for moss to grow. As it turns out this is not always the case. Moss does not actually care about north or south, what is important for moss to grow is the presence of water or moisture.

If you keep this idea in mind, then moss could actually be useful in determining direction when you are lost. You should never count on moss to tell you anything about direction if it is growing near the ground (water is constantly evaporating from the ground creating a perfect environment for moss growth) or high off the ground in areas where there is actually dripping water.

However, if you were to find moss on a surface that was not close to the ground or near areas where water is physically running then there is a really good chance the reason the moss is growing is because the surface is staying moist throughout the day. A good assumption in this case is that the surface is staying moist because it is in the shade most of the day, meaning it is likely growing on the northern side of the surface. So, yes, moss can tell direction is some cases, but you must be aware of your surroundings in order to take advantage of this tool because it could also lead you in the wrong direction!


Answer 3:

The following link takes you to the natural navigator . This information gives a rather good discussion - it is indeed all about where the moisture is.

I would add to the third to last paragraphs ("The best technique is a two-step process. First you need to find some moss, next it is important to ask why that surface is moist.")... the observation that, even after you take into consideration the circumstances listed, you still need to be alert to any other factor that reduces evaporation or that introduces moisture that would favor the growth of moss - on any side of the tree.


Answer 4:

I don't believe so, but you don't need moss. All you need is the sun, which rises in the east, and sets in the west.


Answer 5:

Mosses like to grow in shaded areas (they need dark, moist areas to survive). The heat of the sun is always stronger on areas that face South, so it is less likely for moss to grow on the south facing areas.

HOWEVER, I am geologist (a scientist who studies rocks) so I have done a lot of hiking to see different rocks, and I have seen moss in a lot of different places -- it is not a very reliable source for navigation. Definitely better to use a map and compass, or the direction of the sun.



Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2015 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use