
Hemlock is one of the most common trees in North America, but it’s often overlooked as a firewood choice because it’s a softwood. So, does being a softwood weaken the wood-burning characteristics of firewood?
Let’s find out. In this article, we’ll weigh in on hemlock’s different wood-burning capacities and how to add it to your list of firewood choices.
Is hemlock a good firewood?
Hemlock is an excellent firewood for kindling and fireplaces. It is a slow-burning softwood with a moderate heat output and produces less smoke and creosote when burned.
Hemlock trees can reach 100 feet tall, so you can surely get a lot of firewood from one tree. It’s also abundant in the North American region, so that you can find it in most markets.
They’re great for ambient burns or when you want to warm up your room quickly. It’s good at kindling, so you can use it for campfires or cooking in your wooden stoves.
This firewood is commonly used as a kindling and starter log mixed with hardwoods to maximize its heat output and extend its burn time. However, it does not leave coals behind, making it hard to re-ignite in the morning.
Here’s an overview of the characteristics of the hemlock as firewood.
Tree Name | Hemlock |
Scientific Name | Tsuga sieboldii |
Family | Pinaceae |
Height | 40 to 70 feet |
Life Span | 250 to 300 years |
Type of Wood | Softwood |
Dry Weight (lbs per cord) | 2,474 to 2,917 |
Green Weight (lbs per cord) | 3,495 to 4,250 |
Density | Low |
Seasoning Time | 7 to 12 months(6 to 8 months in warm and dry climates) |
Heat Content (million BTUs per cord) | 19.3 |
Heat Production | Average |
Resin Content | Medium |
Splitting Difficulty | Easy |
Smoke | Low |
Smell | Woody |
Coal Production | Very poor |
Creosote Build-up | Low |
What are the fire characteristics of hemlock as firewood?
As firewood, hemlock has easy splitting difficulty, low resin content, woody smell, low moisture level, moderate heat output, low creosote buildup, low smoke output and very poor coal production.
Let’s discuss each fire property and how they can fit your needs.
1. Easy Splitting Difficulty
Hemlock has a distinctly smooth grain, making it easy to split while still green. It also has low resin content, making it durable and preventing rotting for years.
Hemlock wood can last between 5 to 7 years when correctly seasoned and stored. You can also use it as a raised garden bed, fence or barn.
2. Low Resin Content
Although it is related to sappy pine trees, hemlock did not inherit this family characteristic. Hemlock is considered a non-resinous species because of its extremely low resin content.
However, this tree still produces some resin to deliver the necessary nutrients of other parts of the hemlock tree. So, we recommend that you gather hemlock firewood during winter because this is the time when it produces the least sap to travel to its roots.
3. Woody Smell
Burning hemlock firewood produces an aromatic woody smell as if you’re inside a traditional wood sauna.
It’s ideal firewood for outdoor activities, with its smell completing the campfire vibe and experience. Others love using hemlock as an alternative to expensive cedar in their sauna.
4. Low moisture level
Firewood needs to have a low moisture level so that there’ll be less energy for combustion and less smoke and creosote to produce.
Fortunately, hemlock does not retain water for so long, even though it loves moist and acidic soil. Once it has been cut down, it has a low moisture level.
5. Moderate Heat Output
Because of its low density, hemlock doesn’t burn as hot as other firewood, with a BTU of 19.3 million per cord. You’ll need to burn more wood to get the same heat as hardwood from your fire.
Fortunately, hemlock’s 19.3 BTU and its fire characterize it as lasting longer than other softwoods. It can still produce a warm, long-lasting fire, which is great for campfires and fireplaces.
Here’s how one cord of hemlock firewood works as a heat source. Note that one volume of a cord is equal to 128 cubic feet.
Natural Gas (cubic feet) | 16,300 |
Propane (gallons) | 185 |
Heating oil (gallons) | 120 |
Kilowatt (hours) | 4,900 |
6. Low Creosote Build-Up
Creosote build-up is an essential consideration for firewood. While burning, this wood leaves black, tarry by-products on your flute or chimneys.
You shouldn’t let these creosote accumulate in your home because they are highly flammable and can disrupt the airflow in your fireplace.
The good news is that hemlock firewood has low creosote build-up. This is primarily thanks to hemlock’s low moisture and sap content.
When this firewood is seasoned correctly, leaving under 20% moisture content, you won’t have to worry much because it will produce very little creosote after burning.
7. Low Smoke Output
Still, thanks to its low moisture content, there’s less water inside the firewood to be vaporized while burning. As a result, less vapor means less smoke output.
In hemlock’s case, there’s little moisture left after the seasoning process, so it produces a low smoke output.
You could take advantage of this fire characteristic and use hemlock to cook in an open fire.
8. Very Poor Coal Production
Good firewood needs to produce coals to keep the fire burning.
However, one caveat of using hemlock as firewood is its poor coal production. Hemlock burns up completely, leaving less coal and more ash behind.
On the brighter side, hemlock burns slowly enough to maintain its heat for a long time, even longer than most conifers and chestnut firewood.
What are the varieties of hemlock wood?
Hemlock has three varieties – Mountain, Eastern, and Western hemlock trees. All have low density and burn fast but release different heat outputs.
Below is an overview of each of these hemlock varieties.
Common Name | Mountain Hemlock | Eastern Hemlock | Western Hemlock |
Scientific Name | Tsuga mertensiana | Tsuga canadensis | Tsuga heterophylla |
Distribution | Pacific Northwest America | Eastern United States and Canada | Northwest America |
Height | 60 feet | 60 feet | 100 feet |
Width | 15 feet | 2 feet | 30 |
Density | Low | Low | Low |
Heat Output | 20.1 BTU million per cord | 17.1 million per cord | 17.7 million per cord |
The eastern hemlock is commonly used as a Christmas tree, while its wood is manufactured for plywood, veneer and even paper pulp production.
Image: iNaturalist
Western hemlock thrives in drier areas and has a thin bark, making them easier to penetrate by insects, while the mountain hemlock is a fast-growing tree with a smooth gray bark that’s 4 inches thick.
Image: UK Tree Guide
Although they have a heat output of 17 BTUs, eastern and western hemlock still ranks higher than more fir species.
Image: Wikipedia
The mountain hemlock produces the highest heat output, with a BTU of 20.1, compared with the eastern and western hemlock varieties. In terms of heat output capabilities, it’s also on the same tier as Douglas fir, eastern red cedar and silver maple firewoods.
Pros and Cons of Using Hemlock as Firewood
Here are the advantages and disadvantages of using hemlock as firewood.
Pros | Cons |
Moderate heat output | Moderate sparks |
Easy to split | Very poor coal production |
Easy kindling | Mild woody smell |
Low smoke and creosote output | |
Fast seasoning time | |
Low resin and moisture content |
Hemlock generally produces heat of 19.3 million BTU/cord. Although it’s not a hot burning wood, it still burns long and clean, making it ideal when burning mixed hardwoods.
They’re also easy to split, which makes them a good choice for kindling and starter logs.
Hemlock wood has a relatively fast seasoning time (7 to 12 months). This is largely thanks to its low resin content and low moisture level after cutting.
However, hemlock produces little to no coal but instead leaves ashes behind. Apart from having to swipe these ashes, it is difficult to restart the fire.
As it burns, expect moderate sparks, crackles and pops and a wisp of woody smell. These make hemlock a great firewood choice for a complete campfire experience.
How does hemlock compare with other firewood?
Compared with other softwoods, hemlock performs well in terms of heat output. It even joins the ranks of some hardwoods like silver maple and Sycamore with the same 19 BTU level.
Even if it doesn’t produce coals like oak, maple and beech, it burns slowly enough to last overnight. During winter, you can also use hemlock as kindling firewood and other hardwoods for maximum heat output and longer burn times.
Take a look at how hemlock firewood compares to other firewood.
Firewood | Heat Output (million BTU per cord) | Splitting Difficulty | Coal Production |
Hemlock | 19.3 | Easy | Very Poor |
Black ash | 17.9 | Easy | Good |
Bradford Pear | 26.5 | Hard | Excellent |
Bur Oak | 26 | Easy | Good |
Maple | 25 | Easy | Excellent |
Osage Orange | 32 | Easy | Excellent |
How long should you season hemlock wood?
Hemlock takes only 7 to 12 months to season, making it one of the quickest-drying firewood in the market. Additionally, if you live in a warm and dry climate, hemlock wood can dry as fast as 6 to 8 months.
Compared with a softwood like cedar which takes up to 24 months to season and has a lower BTU, seasoning hemlock wood for 7 to 12 months is more beneficial and efficient, given that it will give you at least 19.1 BTU.
In seasoning hemlock, just as with all other firewood, make sure they’re stored in a dry area with adequate airflow. It would also help to split the hemlock into manageable pieces so that more surface area is left to dry.
FAQs on Hemlock as Firewood
Hemlock trees are unrelated to the poison hemlock plant known for killing the philosopher Socrates.
Hemlock is safe to burn in fireplaces since it produces low creosote and smoke output, making it safe for indoor use.
Hemlock is not toxic to burn because it is a different plant from the poison hemlock.
Hemlock wood is only moderately moisture resistant, but not waterproof. Because of its open pores, hemlock can manage its internal water content and resist decaying, rottenness and shrinking.