If you are outdoors in boreal forest biomes worldwide, it is of primary importance to protect yourself against wind and wetness. And, to light a fire for warmth. The necessary firewood should be dry to burn hotter and with less smoke. But if you are out in the woods, how do you know if your firewood is sufficiently dry or not?
Moisture testing methods
Literature, see this link here, is proposing four different methods of determining if firewood is recommendable for lighting a fire.
- Soap test
- Sound test
- Look at the features of the wood piece
- Moisture meter
I do not want to comment on the soap test and moisture meter method, as both are not suitable out in the forest. The sound test is also not recommendable, as the resulting amplitude and frequency of the sound depend on too many different parameters. Only careful examination of the features of a piece of wood and its growing surroundings will help to determine if it is suitable as firewood. The ‘Dead, Dry and Standing’ guideline should be applied as a standard routine.
And there is one more test for firewood, which is virtually unknown in Western circles. This test is used in the Russian Taiga, where lots of people move regularly into the forests for fishing, hunting, mushroom collection, berry picking, or trapping. Before they light a fire, they check the firewood by holding the freshly cut edge of the wood to their lips. If it feels cold – it’s wet, if it feels warmer – it’s dry. Additionally, to this temperature sensing, they also smell the wood. Their olfactory memory and experience will help them to judge if the wood is dry or not.
Moisture measurements on wood samples
I checked now if this information from a Russian bushcrafter is correct or just a myth. I collected dry and green samples of spruce and wild cherry from the same trees and measured their moisture contents, tested the perceived temperature of the cut area on the lips, and counted the annual rings of the wood samples. Moisture measurements were done with a two-pin moisture meter.
Results of moisture measurements on the wood samples
- Every wood species should be considered separately.
- Spruce
- There were distinctive differences in moisture contents between green and dry wood samples.
- Dry samples feel tentatively warmer on the lips compared to green samples.
- A colder (higher moisture) ring could be felt at the dry samples on the outside surface.
- At high wood densities (many annual rings) the thermo-sensory impression is moving towards a colder feeling.
- Wild cherry
- Showed an overlap of moisture contents amongst green and dry samples.
- The colder temperature throughout the sample could only be felt on the lips of the green sample with high moisture content.
- All dry samples were colder at the core and not on the outside.
- On both wood species, it was possible to sense with closed lips the temperature differences in various areas of the cut.
Summary
Therefore, it can be stated, that the Russian Taiga-method of sensing moisture content with closed lips on freshly cut wood works.
And I would restrict its suitability to coniferous trees under similar growing conditions only. Wood of deciduous trees can only be divided by this method into: ‘completely green’ and ‘somewhat dry’. And as ‘completely green’ wood is very obvious, this method is more suited for coniferous trees. The method of feeling the temperature on the lips is therefore a very practical method. It helps to determine if coniferous firewood is dry and should have its rightful place in all boreal forest biomes of the Northern hemisphere.
Lessons learned about judging if firewood is either wet or dry:
- There are four methods established in Western countries of measuring moisture content in wood
- Two of these methods are not suitable for survivalists, one is partly suitable, and one is connected to logical thinking
- There is one more method by holding the cut wood on the closed lips and feel the temperature
- This method is practical and suitable for coniferous tree woods under similar growing conditions
