Engelmann spruce
A high-elevation spruce with scaly bark and sharp, squarish needles, whose Colorado stands have lost more than a million acres to a beetle since 1996.
Engelmann spruce at a glance
Picea engelmannii EN-gel-mun sprus; Picea engelmannii is PY-see-uh eng-gel-MAN-ee-eye
- Type
- Plant · conifer
- Diet
- Producer
- Lifespan
- Dominant trees in a stand are often 250 to 450 years old. A few are known to reach 760 to 850 years.
- Conservation
- Not federally listed as a species. Colorado State Forest Service reports spruce beetle outbreaks have affected more than 1.7 million acres of Engelmann spruce statewide since 1996, including 350,000 acres in 2016 alone.
Eats sunlight, water, soil nutrients
Photosynthesizes through short, stiff needles that grow singly around the twig. NPS describes it as having scaly bark and squarish needles, unlike the smoother bark and flat needles of the subalpine fir it often grows beside.
Is it safe to touch?
Harmless — no spines, no poison. Its needles are sharp enough to poke a bare hand, unlike the soft needles of the subalpine fir it often grows next to; that's one way to tell the two apart by touch.
Run a hand along a spruce branch and a fir branch growing side by side, and you’ll flinch at one of them. NPS puts the difference plainly: Engelmann spruce has scaly bark and squarish needles, while the subalpine fir next to it has smoother, gray bark and flat needles. The spruce pokes. The fir doesn’t. That’s the whole test, and it works without a field guide.
Engelmann spruce is also a latecomer by design. NPS describes spruce-fir forest moving in only after lodgepole pine and quaking aspen have already grown up and stabilized the soil — the spruce inherits ground that other trees prepared first, then holds it for centuries in cool, moist stands near treeline.
Lately something smaller than a grain of rice has been taking that ground back. Colorado State Forest Service reports that spruce beetle outbreaks — driven by windthrown trees, drought, warmer winters, and dense stands of old growth — have killed Engelmann spruce across more than 1.7 million acres of Colorado since 1996, 350,000 acres in 2016 alone. The dead stands turn gray-brown and stand there a long time, and the state forest service notes they can help fuel the next big wildfire through the very ground the spruce spent so long claiming.
Did you know?
- Engelmann spruce is one of the trees that moves into a forest only after lodgepole pine and quaking aspen have already stabilized the soil.
- You can identify it by touch: it has scaly bark and squarish needles, while the subalpine fir growing next to it has smoother, gray bark and flat needles.
- A single insect, the spruce beetle, has killed Engelmann spruce across more than 1.7 million acres of Colorado since 1996.
Common questions
How do you tell Engelmann spruce from subalpine fir?
By touch. The spruce has scaly bark and squarish needles that poke; the fir growing next to it has smoother, gray bark and flat needles that don't.
Why does Engelmann spruce grow where it does?
NPS explains it moves into a forest after lodgepole pine and quaking aspen have already grown up and stabilized the soil, making room for slower, longer-lived trees.
What is killing Engelmann spruce in Colorado?
The spruce beetle. Colorado State Forest Service reports outbreaks tied to blowdown, drought, warmer temperatures, and dense stands of older trees have affected more than 1.7 million acres statewide since 1996.
Is a dead, gray forest of Engelmann spruce more likely to burn?
Colorado State Forest Service notes beetle-killed trees can help fuel large, intense wildfires.