Not All Cedars Are Cedars

Why a forest can be full of cedars without containing a single true cedar

Echo made the mistake of saying one word.

“Cedar.”

There are situations in the forest where a one-word identification is perfectly adequate. A rock is a rock. A mushroom can remain “mushroom” until somebody decides whether touching it is a good idea. And if the animal in the bushes is large enough, “bear” contains essentially all the information required for the next several seconds.

But Echo was standing beside Otto.

And the tree was a western redcedar.

So “cedar” was never going to survive unqualified.

“Western redcedar,” Otto corrected.

“That’s what I said.”

Then Otto committed the sentence that ensured neither of them would be leaving anytime soon.

“It isn’t actually a cedar.”

Echo looked at the tree.

Then at Otto.

“It’s named cedar.”

“Yes.”

That is where the trouble begins.

First, the actual cedars

True cedars belong to the genus Cedrus, in the pine family.

For this field note, we’re treating three as the commonly recognized species:

• Atlas cedar

• Deodar cedar

• Cedar of Lebanon

Cyprus cedar is also sometimes recognized separately, although many authorities treat it as a subspecies of cedar of Lebanon.

True cedars carry their needles in dense clusters on short shoots, and their cones sit upright on the branches like little barrels.

And there is one particularly important detail.

None of them are native to North America.

If you find a true cedar growing in the Pacific Northwest, somebody planted it.

Possibly a very long time ago.

Older neighborhoods sometimes contain enormous deodar cedars planted when both the house and the person holding the shovel were considerably smaller. The tree eventually interpreted “ornamental” as a temporary job description.

So the strange situation is this:

The forest contains no true cedars.

And is nevertheless full of them.

The four locals

Around here, four native trees regularly carry “cedar” in their common names.

They belong to four different genera.

Western redcedar — Thuja plicata

The giant at the bend in the trail.

Flat sprays of scale-like foliage. Fibrous, stringy bark. Massive old trunks. Aromatic wood with remarkably durable heartwood.

It belongs to the cypress family, Cupressaceae.

Not Cedrus.

Incense-cedar — Calocedrus decurrens

A tree of somewhat drier country, especially farther south, with flattened foliage and strongly aromatic wood.

If you have ever sharpened a wooden pencil, there is a good chance you have encountered something very much like that smell.

Port-Orford-cedar — Chamaecyparis lawsoniana

A beautiful conifer with a relatively restricted native range in southwestern Oregon and northwestern California.

Its wood has long been valued, while the tree itself now faces serious problems from an introduced root disease.

That is a different field note.

And a considerably sadder one.

Alaska-cedar — Callitropsis nootkatensis

A slow-growing tree of cool, wet country, often recognizable by its long, drooping sprays of foliage.

Some modest-looking individuals may have been standing for centuries.

Four “cedars.”

Four genera.

No Cedrus.

At this point Echo’s long-standing suspicion that plant names were designed specifically to irritate him was becoming difficult to dismiss.

Then there’s eastern redcedar

Surely eastern redcedar will restore some order.

It has “redcedar” right there in the name.

It is a juniper.

Juniperus virginiana.

Those blue, berry-like structures are not berries at all. They are modified cones whose scales have become soft and fleshy rather than woody.

And the aromatic reddish wood historically used for many “cedar” chests in North America was very often eastern redcedar.

So the tree is exceptionally good at doing things people associate with cedar.

It simply has no interest in being one botanically.

This is why Echo owns a wooden NO sign.

Some tools are simply worth carrying.

A brief moment of botanical humility

Before botanists become too smug about common names, there is something Otto has to admit.

Scientific names change too.

Alaska-cedar has been placed in several different genera since it was first described in the nineteenth century as botanists have argued over its relationships and incorporated new evidence.

It has spent time in Cupressus, Chamaecyparis, Xanthocyparis, and Callitropsis.

Echo noticed the weakness immediately.

“So both names keep changing.”

Otto’s defense was technically accurate and emotionally weak.

“Ours have footnotes.”

He is not wrong.

Scientific names are meant to reflect biological relationships, and they change when our understanding of those relationships changes. Ideally, the change comes with evidence and a published explanation attached.

Common names change for very different reasons.

Or sometimes they do not change at all.

Neither system is perfectly motionless.

One simply comes with considerably more paperwork.

And then Spanish cedar makes everything worse

By now, you might think you have found the pattern.

Perhaps “cedar” is simply an informal name people applied to various members of the cypress family.

Not technically correct, but at least all the trees are conifers.

Then Spanish cedar arrives.

Spanish cedar is Cedrela odorata.

It belongs to the mahogany family.

It is a broadleaf tree.

Not a conifer.

No needles.

No conifer cones.

No botanical relationship to Cedrus that would justify the name in the way Otto would prefer.

Its aromatic wood has long been valued for uses such as boxes and other specialty woodworking, and its smell is one reason the cedar comparison persisted.

Echo tried guessing anyway.

“Cypress?”

No.

“Juniper?”

No.

“Mahogany family.”

There are expressions a raven can make without moving a single feather.

That was one of them.

And this is where the story becomes more interesting than simply saying people were bad at naming trees.

Because common names were usually not trying to answer the same question scientific names are trying to answer.

Common names aren’t family trees

Scientific classification is primarily trying to tell us about relationships.

What is this organism?

What is it related to?

Where does it belong on the evolutionary tree?

Common names often developed around much more immediate observations.

What does it look like?

What does it smell like?

What is the wood like?

Does it split cleanly?

Will it last outside?

Can I build something useful with it?

Does it remind me of a tree I already know?

That difference explains a great deal of botanical naming chaos.

The people applying familiar names to unfamiliar trees were not necessarily attempting to construct a phylogenetic system.

They were encountering plants in the real world.

They were cutting wood.

Building houses.

Making shingles, posts, boxes, boats, tools, and furniture.

And they were noticing characteristics.

Aromatic wood.

Relatively light wood.

Wood that splits well.

Wood that lasts.

Once a familiar word became associated with a useful combination of traits, that name could travel remarkably far from its botanical starting point.

The common name was answering a practical question.

The scientific name was answering a biological one.

Those answers do not always match.

Why unrelated trees keep earning the same name

Here is the part that makes this more than a story about human sloppiness.

A lot of unrelated trees genuinely do similar things.

In a wet forest, wood is valuable tissue.

And fungi would very much like to eat it.

Large, long-lived trees benefit enormously from making their heartwood difficult to decompose. Different tree lineages have evolved different chemical defenses that can slow decay and make their wood less inviting to fungi and other organisms.

Western redcedar is particularly famous for this.

Its heartwood contains natural compounds that contribute to its resistance to decay.

Junipers reach similar practical outcomes with different chemistry.

Other so-called cedars have their own defenses.

The chemistry differs.

The evolutionary histories differ.

But to the person cutting the wood, the results can look surprisingly familiar:

Durable.

Aromatic.

Useful.

Long-lasting.

So the trees arrived at similar practical properties by different evolutionary routes.

And humans arrived at the same word.

The trees converged on a strategy.

Humans, walking around with axes and noses, converged on a name.

Western redcedar really did earn the reputation

This is where Otto’s argument starts becoming uncomfortable.

“Western redcedar” is taxonomically misleading.

The tree is not a member of Cedrus.

If the common name were trying to describe ancestry, it would be doing a terrible job.

But the name is not meaningless.

Western redcedar really does have remarkably durable heartwood.

Its wood contains compounds that help it resist decay, which contributed to its long-standing reputation for outdoor use.

To generations of people working with wood, the word “cedar” could suggest something practical:

Aromatic.

Durable.

Useful.

Resistant to decay.

The name is wrong on the family tree.

And still capable of communicating something real about the material.

Echo got there first.

“So the name is wrong on the family tree… and useful in the real world.”

Otto looked at the redcedar.

Then at his notes.

Then at Echo.

“…Annoyingly, yes.”

A name can be wrong without being useless

This is the part Otto finds genuinely difficult.

Common names are not miniature taxonomic keys.

They are historical fingerprints.

They can preserve what people noticed first.

What something resembled.

Where it grew.

How it smelled.

What people built from it.

What somebody had already been calling it for generations before anyone arrived with a herbarium specimen and a Latin name.

That makes common names unreliable guides to evolutionary relationships.

It also makes them interesting.

A scientific name is trying to tell you where an organism belongs.

A common name can tell you something about how people encountered it.

Those are different kinds of information.

Sometimes both are useful.

And sometimes the common name survives precisely because it continues to make sense in the everyday world even after botany has explained why it makes no sense on the family tree.

That does not make the name scientifically precise.

It makes it culturally persistent.

Which, for a tree famous for durable wood, feels oddly appropriate.

Standing at the overlook

By late afternoon, Otto and Echo finally reached the overlook.

Below them stretched thousands of acres of conifer forest.

Western redcedar scattered through the drainages.

Other so-called cedars farther beyond the horizon.

Not a true Cedrus anywhere in sight.

Echo stared out over the forest.

“So ‘cedar’ isn’t a family.”

He thought about it.

“It’s a smell.”

Otto considered explaining that this was an oversimplification involving wood chemistry, history, cultural use, convergent traits, and several centuries of inconsistent naming.

Then he remembered how the afternoon had started.

“It’s a smell that stuck.”

Echo nodded.

For once, no further correction was required.

In the field

If you actually want to know which “cedar” you are standing under, ignore the common name for a moment and look at the tree.

Flat sprays of scale-like foliage with fibrous, stringy bark in a moist Pacific Northwest forest?
Western redcedar is a strong possibility.

Prickly or scale-like foliage with soft blue, berry-like cones?
You may be looking at a juniper.

Needles gathered in dense clusters on short shoots, with barrel-shaped cones sitting upright on the branches?

Congratulations.

You may actually have found a true cedar.

Somebody probably planted it.

COMMON NAMES: MAKING SENSE FOR ALL THE WRONG REASONS.