Fir vs. Spruce: What’s the Difference?
Fir or spruce? It can sometimes be impossible to tell. Have no fear, as this guide breaks down the differences between two main genera of conifers, Abies (fir) and Picea (spruce). Use this guide to help you differentiate between the two.
New growth on a species of Picea.
Conifers are a tricky group to identify. They are all evergreen, they all have needles of some sort, and many of them reproduce through their female cones that bear seeds. Now, because conifers all share these characteristics, we can use them to differentiate the genera and species of each tree.
In the Pacific Northwest, there is a large number of conifers in a few different genera. In this article, we will be focusing on two main genera, Abies (fir) and Picea (spruce). We’ll look to these trees’ needles, cones, and bark to determine which tree is which.
Without further ado, here are tips and tricks on how to tell a fir (Abies) from a spruce (Picea). We’ll also learn which trees in each genus dominate the Pacific Northwest.
Leaves
Conifer leaves are called needles, as they resemble sewing needles and are linear in shape. Fir tree needles differ from spruce needles in a few different ways.
Fir trees (Abies) have flat needles, and these needles leave a smooth scar when plucked from the branch. If you rub your hand along a fir tree (Abies) branch, you’ll notice the branch is smooth where the needles used to be. This is not the case with spruce branches.
A spruce tree (Picea) is different. It has needles that are sharp at the ends, and they are often arranged circularly like a bottlebrush. When plucked from the branch, these needles leave a peg-like wooden structure. If you rub your hand along a spruce tree (Picea) you’ll notice the branch is rough, and it consists of many left-over pegs.
Cones
The easiest way to discern between a tree in the genus Abies from Picea is by the trees’ cones. Cones on a fir tree (Abies) will always grow upright, and they typically grow on the uppermost branches. Fir trees are the only conifers with cones that grow upright.
Abies procera with upright cones. Photo credits: Jerzy Strzelecki
Above is an example of a beautiful native fir tree, Abies procera. Known commonly as the noble fir, this fir tree has stunning upright cones that mature to a beautiful dark brown. Fun fact, this tree is commonly grown in Christmas tree farms and sold as a Christmas tree. In the wild, it matures to over 200 feet!
Cones of trees in the genus Abies never reach the ground fully intact. They break apart on the tree to reveal the cones’ seeds. This is why you’ll be hard-pressed to find fully formed fir cones on the ground around a mature fir tree.
Spruce cones (Picea) differ from fir cones (Abies) in that they hang downward. Spruce cones mature on the tree, and they will drop to the ground when fully mature. Because these cones stay intact and do not break apart, you can readily find them on the ground around a full-grown spruce tree.
There is one other tree with cones to mention here, and that is Pseudotsuga menziesii “Douglas fir.” This tree has “fir” in its common name, although it is not a fir at all. True firs are in the completely different genus Abies, while Douglas firs are in their own genus Pseudotsuga. Douglas firs differ from true firs and spruce in that they hold onto their cones year-round, and they always have cones on their branches.
Another easy trick to discern a Douglas fir from other conifers is the shape the seed bracts make on a Douglas fir cone. Look closely, and you’ll notice the seed bracts look like little mice diving into the cone. Spruce and true fir cones lack this discernable feature, as it is unique to the Douglas fir (Pseudotsuga menziesii).
Pseudotsuga menziesii “Douglas fir” cone with “mice” jumping inside.
Cone on a Picea breweriana “weeping spruce.” Photo credits: Meneerke bloem
To avoid confusion when speaking about plants I always recommend using the plants’ scientific names. These names help avoid confusion and misidentification, and they are universal the world over. Common names can vary from region to region, so they are unreliable when identifying plants.
Bark
Using the bark of a tree alone is a difficult way to tell between a fir or spruce, although it can come in handy when used with the trees’ other discernible features. Typically young conifers will have smooth bark, and mature specimens will have rough, furrowed bark.
It would be difficult to generalize the bark type of a whole genus, as each species can have unique bark features. I like to try and guess what conifer the tree is based on its needles and cones. Then, once I guess what tree it is, I’ll look at the bark to confirm the tree.
Native Firs and Spruce in the PNW
These are the most common native firs and spruces in the Pacific Northwest. If you see a wild fir or spruce tree in this region, it is most likely one of these trees:
Abies (fir)
Abies concolor “white fir”
Abies grandis “grand fir”
Abies lasiocarpa “subalpine fir”
Abies magnifica var. shastensis “Shasta red fir”
Abies procera “noble fir”
Abies amabilis “Pacific silver fir”
Picea (spruce)
Picea breweriana “weeping spruce”
Picea sitchensis “Sitka spruce”
Picea engelmannnii “Engelmann spruce”
Conclusion
Identifying the trees in your local area can be a great way to connect with nature on a deeper level. Conifers can be difficult to identify, but learning the characteristics of each genus and species can make the process easier. By understanding the differences between firs and spruces, such as their leaves, cones, and bark, you can appreciate the unique qualities of each tree and gain a greater appreciation for the natural world around you.
Knowing the native firs and spruces in your region can help you better understand the ecological communities and habitats that exist in your area. So get outside, explore your surroundings, and see how many different trees you can identify!
Got questions? Let me know in the comments section below.
Sources
Kruckeberg, Arthur R, and Linda Chalker-Scott. Gardening with Native Plants of the Pacific Northwest. Seattle, University Of Washington Press, 2019.
All photos taken by Jerad Bryant unless stated otherwise.
