Does Wood Species Affect Your Moisture Meter Readings?
If you take a walk in the woods, you’ll see different kinds of trees. And naturally, each tree species—whether pine, fir, cedar, oak, cherry, etc.—has a different type of wood.
Some wood species are denser than others. Hardwoods, such as oak, tend to be denser than pine, fir, or other softwoods. Each species also has a unique chemical composition. These factors make each species unique, but these factors can also impact your moisture readings.
That’s why, in this article, you learn all about the relationship between wood species and your moisture readings.
You’ll explore questions like:
- How does wood species affect moisture meter readings?
- How do I make corrections for wood species?
- How do I know the correct reading for my specific project?
So keep reading to make sure you know the steps to take to make sure your readings are accurate!
How does wood species affect moisture meter readings?
Wood species impacts moisture readings for both pin and pinless moisture meters but in different ways. Let’s look at each one individually.
When using a pin-type meter, your moisture content readings will be impacted by the electrical resistance of the species that you are measuring.
Let’s break this down a little bit in order to understand it better.
Wood is dielectric, which means it’s a pretty bad conductor of electricity.
It’s made out of insulating compounds like cellulose, hemicellulose, and lignins.
These compounds/molecules are made up of atoms that cling tightly to their electrons and, therefore, don’t allow electrons to move freely, so electricity can’t pass through them.
This means that when met with a source of electric current, the wood’s composition is going to make it difficult for that current to flow.
But, different species of wood have different chemical compositions. Factors like the soil and region a tree grows in can also impact the chemical composition.
The varying chemicals and compounds that make up a wood species—particularly metal ions and water—change the way that electricity can move through the wood. For example, water, because of its impurities, and metal tend to be conductors of electricity. The more of those that a wood species has, the better electricity can move through the wood.
This can pose a problem for those of us wanting to use wood in projects because electrical resistance is also what pin meters use to determine the moisture content (MC) of a piece of wood.
In other words, different wood species can have different MCs and can skew your pin meter’s readings if you don’t know how to correct for wood species or input the correct species setting into your meter—but more on that later.
Pinless meters are impacted by species in a different way than pin-type meters. Instead of chemical composition and electrical resistance, they’re affected by the specific gravity of the wood.
Specific gravity is a way to measure the density, so how dense the wood is will skew the moisture content measurement of a pinless meter.
For example, pine and cedar are light woods, whereas hardwoods like oak, maple, or walnut are heavier and denser.
And density is directly related to the moisture reading. The higher the density, the higher the moisture reading, so it’s important to know how to adjust for this difference in your moisture meter.
Whether you’re using a pin or pinless meter, accurate moisture readings are important. Keep reading to find out how to get accurate readings by adjusting for species.
Why adjusting for species matters
At the end of the day, if you aren’t correcting for species, then your moisture meter won’t give you proper moisture readings. If you don’t have proper moisture readings, then you don’t have the information you need to make good project decisions. The result: your wood might shrink or swell unexpectedly because it’s not at the proper MC.
It’s so worth it to know how to adjust for wood species with your moisture meter. That way, no matter what wood you’re working with, you can be confident that you have the right data to plan your project.
And you’re in luck because this next section is all about how to make corrections for wood species.
How to make wood species corrections
Whether you’re working with a pin or pinless meter, you need to make corrections for wood species whenever you measure MC.
The first thing you want to start with is the species input on the meter itself.
If you’re working with a Bessemeter pinless meter, there is a species button dedicated to this.
When you press this button, you can program your meter with the specific gravity setting for the wood species you are testing. No need to have the specific gravity for each type of wood memorized. Bessemeter’s pinless meters come with a species settings table that tells you what specific gravity setting to use for your specific species. Easy as 1-2-3!
If you’re not using a Bessemeter meter and your moisture meter doesn’t come with the option to adjust for species, you’ll want to make sure that it does come with a table to help you adjust your readings for species.
Each moisture meter is different, so a table for one meter might not work for another, which can render your MC readings unusable.
Whether your meter comes with a built-in correction for species—like all Bessemeter meters—or comes with a chart to correct your reading for species, the option to adjust for species is the mark of a high-quality meter. Without this built-in feature or a species correction table, your MC readings might be of no help.
Recommended moisture readings: EMC is the ticket
Now that you know how to correct for species, you are better equipped to succeed in your wood projects.
To determine the recommended MC for your project, it’s important to also know the EMC of your location.
Equilibrium moisture content, or EMC, is the MC that wood must reach in order to stabilize. EMC varies by region, and you can learn more about it in our article all about EMC.
But in terms of the desired MC for your projects, the biggest factors that will impact the MC you want are the ambient temperature and relative humidity where your project is located.
If you are working on an outdoor project or on a construction project, then an MC below 19% is a good goal because above 19%, mold starts to grow.
For indoor projects, your MC should closely match the EMC of the region!
So, long story short, EMC is the factor you should focus on when figuring out what the recommended moisture reading is for your project. If the EMC is 16%, then the MC of your wood should be 16% too.
Get an accurate moisture measurement for project success
Your MC measurement is only helpful insofar as it’s accurate—species correction is one way to ensure that.
With Bessemeter’s wood moisture meters, you can correct for species so that the number you see on the meter display is the one that’s going to be the most helpful.
Stop worrying about moisture-related failure and start setting yourself up for project success with Bessemeter’s high-quality line of moisture meters.