The official State Tree of Colorado is the Colorado blue spruce, Picea pungens. This post will cover everything you need to know about foraging spruce trees, including identification, look-alikes, habitats, foraging, mushroom associates, and recipes!
Identifying Spruce Trees
In Colorado, we have two native species of spruce: Colorado blue spruce and Engelmann spruce, Picea engelmannii. These two are similar and can occasionally grow together, but there are a few ways to tell them apart! First, though, let's talk about differentiating spruce from other coniferous species. The main identification traits to pay attention to for spruces are the following:
The shape is generally conical, occasionally spire-like.
Bark is scaly and can be grey to reddish depending on species.
Needles are 4-sided and grow around the entire branch.
Needles attach to branches on small pegs called sterigmata.
Cones hang from branches and are composed of many thin scales.
The species most often mistaken for spruces in Colorado are probably firs, Abies spp., and Douglas fir, Pseudotsuga menziesii, which isn't a true fir but a false hemlock. Pseudo is false and tsuga is the hemlock genus. We will go into more detail when I write articles for these species, but for now, here are some quick details to differentiate them. Fir needles are flat with rounded tips. They crowd the upper side of their branches, often bending upwards. Their cones are erect, standing vertically from the branches, and fall apart at maturity.
Douglas fir needles look like a mix of spruce and fir. They are flat, a little pointed, and grow around the branches. Their cones grow hanging from the branches and have distinct 3-pointed bracts emerging from under their scales. A cute visualization for Douglas fir cones is to think of a mouse half hiding under their cone scales, its tail and back legs hanging out.
It's pretty simple to tell a spruce from fir or Doug fir, right? Differentiating between our two spruce species gets a little more complicated because they can look very similar until you get used to their macro-differences. For starters, blue spruce isn't always blue. They're often the same green color that Engelmann spruce exhibits, so you can't rely on color to tell these two apart. Below, you will see a table showing some of the differences between the two species on a macro and micro level! The mnemonic device that I always remember is:
"Bristly Blue, Friendly Mann"
This refers to the friendliness of each species if you were to reach out and give them a handshake. Colorado blue spruce needles tend to be sharper and stiffer and grow off their branches closer to a 90-degree angle. Engelmann needles are a little less sharp and grow at more of a 45-degree angle or so. This isn't perfect, but it's a quick and easy way to remember one of their differences! Check out the table for some others!
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Where to Find Spruces
So, now that we understand how to differentiate our spruces from similar-looking species and each other let's talk about where they grow and why you should know how to identify them confidently! In general, our two spruces have quite a bit of habitat overlap, but they also have some preferences. Blue spruce will grow slightly lower in elevation, even down around 7,000ft naturally, whereas Engelmann prefers slightly higher climates from about 8,000ft and up. Both species can grow to a tree line around 11,000 to 12,000ft, though Engelmann prefers that habitat. So much so that they will often join the scrubby subalpine fir, Abies lasiocarpa, in krummholz form. Krummholz is German for twisted wood and refers to the stunted, scraggly, twisted trees growing in the harsh conditions of the alpine habitat. Additionally, blue spruce prefers the sandier habitats along mountain streams and grassy bottomlands, whereas Engelmann tends to inhabit the typical spruce-fir forests found all over our upper elevations.
Spruces are also a very common landscape species outside their natural habitats. I can see half a dozen mature blue spruce from the window by my desk! In my experience, blue spruce tends to be the better choice for landscape trees as they tolerate the lower elevations a bit better. Some other species, varieties, and cultivars are common in these settings, but those aren't really within the scope of this article. If you live in one of the urban areas around Colorado, I would be willing to bet you can find a spruce without too much trouble!
Foraging Spruce Trees
Now, there are a couple of good reasons to be familiar with your spruces besides just tree identification, though tree ID is a good enough reason on its own! They have some pretty tasty edible parts, namely the fresh new growth aptly called tips, and because they are a very important mycorrhizal associate for a handful of our prized edible mushroom species!
First, the foraging! Spruce tips aren't the only edible part of spruce trees but are the most practical and worthwhile. Historically, the cambium (inner bark layer) and seeds were harvested and used as food sources. Still, unless you have spruces on your property I would suggest against cutting into them for the cambium layer, and the seeds are pretty tiny! I will note that while doing some research I learned that spruce cambium is used while making certain cheeses! That's pretty cool, but I digress, the tips are where it's at when it comes to eating your spruces!
The new growth starts to emerge from the ends of their branches around the middle of May in the Front Range and cascades up in elevation as the warmth climbs our mountains. I often see fresh new growth in July above 10,000ft. These tips will be initially covered in a papery husk that is quickly shed as they sprout. This also happens to be the best time to forage them. At this point, the needles will still be pretty tightly packed together, and the tips will be nice and tender. Before you go too crazy, try some tips fresh off the tree! Each tree has unique flavors. Some are more bitter than others. Some are lemony, while others are very piney. If you like them fresh, you'll also like them in your cooking!
Each branch will have several new growth points on a healthy, mature tree. Not all spruces will exhibit this type of growth, especially the naturally occurring ones in the mountains, but if you have access to some healthy urban trees, you can see this sort of production! Remember to practice your sustainable foraging, though! Spread out your collecting. Never take too many from one area or a single tree, and never take the terminal growth at the top of a young tree, as this will stunt its growth. Also, if the tree you're collecting from is on your property, you can strategically collect tips from certain areas if the new growth is starting to encroach on some territory where it doesn't belong. You may see some strange growth and coloration on some tips. This is a gall caused by an insect called an adelgid. It's pretty common. Skip the infected tips.
Spruce tips are a lovely addition to my urban spring foraging and summer mountain foraging! I highly recommend you add it to your repertoire. So, here are some recipe ideas to motivate you as if you weren't already! Most of these sources also have other spruce tips recipes, so peruse a bit and get ready to be inspired.
Spruce tip recipes:
Mycorrhizal Mushroom Associates
Alright! The final piece of the spruce puzzle, let's talk about their fungal associates! Knowing your trees will greatly improve your abilities as a mushroom hunter. Tons of mushrooms we seek to make a meal out of are mycorrhizal, meaning they have symbiotic relationships with trees. In basic terms, the fungi's mycelium attaches to the trees' roots, creating a network where both can share resources. Food for the fungi, increased water and nutrient uptake for the trees! Spruces are a super important associate tree for many species of mycorrhizal fungi, we won't cover all of them, just the ones that most of us want to eat! I should add that spruces aren't the only associate for these species. Some of them also like firs, some like pines, and some will even associate with hardwoods in other states, but they all agree that they like spruces!
Mycorrhizal associates for spruce trees:
Some species of saffron milkcaps, Lactarius deliciosus group
Sheep polypore and its unnamed fruity friend, Albatrellus ovinus and A. confluens
Note - Some people find S. imbricatus and A. confluens to be bitter.
As mentioned, this list isn't exhaustive, but it shows how important spruce trees are to our local fungi! Of all these species, I would suggest learning how the king boletes associate with spruce first. I think it's really the most fulfilling one when you figure it out! To get started, look for areas with mature spruces, and within those forests, find edges such as meadows, old logging roads or logged areas, forest clearings, etc. If the conditions are good and your timing is right you'll be blown away at what you can find! Every once in a while, I get it right and run into more perfect bolete buttons than I can carry. It's quite the sight, and I hope you get to experience it for yourself someday!
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