Completely Arbortrary

Latest Episodes:

How Casey Learned to Stop Worrying and Love the Apple (Apple 3) Mar 05, 2026

Show notes

260 episodes and 5 years later, and Casey has found an apple he loves, (Malus hupehensis), which he dubs by far the most interesting apple in the world.

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

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Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Are You There, Fog? (Coast Redwood 2) Feb 26, 2026

Show notes

Fog: the coast redwood's strongest ally through a process called folial uptake.

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Reinventing the (Wheel Tree) Feb 19, 2026

Show notes

Don't go reinventing the wheel tree (Trochodendron aralioides), it certainly isn't.

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Even Older Growth (Western Juniper 2) Feb 12, 2026

Show notes

You’ve heard of old growth forest… but how about old growth woodland? For more info, ask the western juniper (Juniperus occidentalis), a tree that is helping to redefine the meaning of old growth. Then, we play a brand new game!

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Renaissance Tree (Superb Schima) Feb 05, 2026

Show notes

A tree that lacks nothing… except for name recognition: the superb schima (Schima superba) (yes, that is its real name.)

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Cones on the Spectrum (Celerytop-Pine) Jan 29, 2026

Show notes

Forget everything you thought you knew about conifers, and make way for the celerytop-pine (Phyllocladus aspleniifolius) with leaves and cones like no other, and raises the question “what is a conifer”?

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Evolutionary Naïveté (Blue Ash) Jan 22, 2026

Show notes

When the emerald ash borer came to North America, few ashes survived. But one native species, the blue ash (Fraxinus quadrangulata), survived. How did this lucky survivor beat the odds?

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Bird Influence (Limber Pine) Jan 15, 2026

Show notes

Today we discuss our flexible friend the limber pine (Pinus flexilis) and its curious co-evolutionary relationship with, you guessed it, BIRDS.

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Burning Hot Fresh Root News (Scots Pine) Jan 08, 2026

Show notes

Welcome to Season X of Completely Arbortrary, our final hoorah! To begin the end, we talk about senses of smell and the Scots pine (Pinus sylvestris).

Completely Arbortrary is produced and hosted by Casey Clapp and Alex Crowson

Support the pod and become a Treemium Member

Follow along on Instagram

Find Arbortrary merch on our store

Find additional reading on our website

Cover art by Jillian Barthold

Music by Aves and The Mini-Vandals

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It's The End of Completely Arbortrary (As We Know It) Jan 01, 2026

Show notes

It's been 5 years of weekly tree podcasts, but after this final season, Casey and Alex will be moseying on to the next chapter for an extended hiatus. Buckle up for THE FINAL SEASON of Completely Arbortrary.

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.