Saturday, January 12, 2019

In Search of a Tree, 2019

January 2019 has arrived, and we tree-followers are faced with an important decision: What tree to follow? In years past, I’ve chosen a birch in my yard (convenient), a limber pine in the mountains east of town (spectacular habitat but immutable tree, and inaccessible in winter), a large cottonwood along the Laramie River (plenty of action and entertaining history), a willow in the foothills east of town (fascinating tree, pleasant hike), a juneberry at a plains lake south of town (inconvenient in winter), a fossilized extinct palm tree that grew 300 miles away (failed in two attempts to visit the site due to snowstorms), and last year a scrappy little boxelder next to a warehouse just a block from my house. The boxelder and the willow are my favorites so far.
Old Main, the beginning of the University of Wyoming, with old blue spruce.
This year I'm going to choose a tree on the University of Wyoming campus. It’s close by, and the landscaping includes deciduous trees (I'm done with conifers and fossils). I started my search in the large open space on the southwest corner of campus (above, in part), just south of the Aven Nelson Building (Botany Department). The vegetation is mainly grass and conifers, but the walkways are lined with flowerbeds (currently empty), and there are deciduous hardwoods scattered about.
In the background is the Aven Nelson Building and the Williams Conservatory.
A place to rest during tree-following.

Since it’s January, these trees have only scattered shriveled dead leaves. But let’s use our imaginations to visit them in a different time—specifically June of 2006. There’s no snow, the grass is green, and the flowerbeds along the walkways are brilliant with color: green, red, purple, yellow. The deciduous trees are fully leafed out, and beneath each one are three or four people, clustered together. They look closely at branches and bark, examine any leaves and buds within reach, stare at something in their hands, and then chat among themselves. They repeat this behavior until smiles appear on their faces. They are identifying trees with dichotomous keys.
During the mid 2000s (the “aughts”), I taught the summer taxonomy/field botany course at the University. It was always a pleasure, with enthusiastic students. Tax/field botany courses often start with an exercise in using a dichotomous key—a series of paired choices each of which eliminates a set of candidates, leading finally to the correct identification. The introductory exercise is often done with objects such as bolts, nuts, screws and nails, of various sizes (seriously!), but fortunately there were lots of trees near the Aven Nelson Building. We also had a wonderful little book—the Rocky Mountain Tree Finder (1). It’s easy and fun to use, and it works! In fact, it seems like magic the first few times you try it.
Now let’s return to that summer long ago. This time we will eavesdrop: “Are the leaves simple or compound—made up of several leaflets?” pause “Not sure, what’s a leaflet?” “Here, look at the picture.” “Nope, not compound.” “Do the leaves grow opposite each other on the stem or alternate?” “Looks opposite, let’s go with that.” “Is the leaf lobed? Here, look at the drawing.” “Yes” “Do the lobes have teeth on the margins?” Another little drawing … “Yes.” “Then it’s a Rocky Mountain Maple.” They call and wave me over, and I agree with them. “Wow, that’s so cool!” someone says, and they move on.
Opposite simple lobed leaves of Rocky Mountain Maple (courtesy TreeLib).
The groups shift from tree to tree, refining their skills. Then a most amazing thing happens. A University truck pulls up and parks close by. Two men get out, unload a small tree, and plant it! We stare in disbelief, then someone starts laughing and we all join in. “They brought us another tree to identify!”

The “surprise tree” 12.5 years later.
As you can see, the surprise tree is still alive. Of course I don’t remember its identity, or even if someone keyed it out. But I can see from the few dead leaves that it’s an oak. Is it one of our two natives? Possibly, based on leaf shape. Is it old enough to bloom and produce acorns? Not sure—still pretty small. Should I follow it? I’m tempted … such great memories! But for now, I will keep looking.

I want to end this post with a heartfelt “Thanks!” to Lucy Corrander of Loose and Leafy in Halifax, who introduced me and many others to tree-following. I so enjoy choosing and getting to know a tree each year, and will always be grateful for this. As many know, Lucy recently posted that she’s undergoing extended difficult medical treatment. My thoughts are with you, Lucy … best wishes to the original tree-follower!!


(1) The Rocky Mountain Tree Finder is just one in a series of tree, flower, cactus and other plant finders.

Friday, December 21, 2018

Holiday Greetings in Wyoming Red & Green

Ever wonder why red and green are the colors of Christmas?
Back when Christmas was mainly religious, red and green represented the Holly Tree, which Christians considered symbolic of the crown of thorns worn by Jesus (others considered it a symbol of fertility, or a charm to ward off witches and bad luck).
European holly, Ilex aquifolium (source).
The Holly Tree of Christmas, Ilex aquifolium, is restricted to Europe. In Wyoming we have no hollies at all, and the nearest members of the genus Ilex grow in the southeastern United States. So we have to be creative in making homegrown botanical Christmas cards. This year I chose rich red paintbrush bracts and pale blue-green sagebrush leaves—symbolic of the sagebrush steppe that covers so much of the state.
Sagebrush steppe northwest of Daniel, Wyoming. Photo by Matt Lavin.
Photo courtesy US Fish & Wildlife Service.
Red “flowers” of paintbrush (Castilleja) are actually bracts; flowers are yellow (click image to view).
Finely-hairy drought-resistant leaves of sagebrush (Artemisia tridentata) contain camphor and other volatile oils, suggesting true sage when crushed (source).
This plant pair wasn’t just a lucky find. Paintbrush often grows next to a sagebrush, its roots penetrating the sagebrush roots to siphon off water and nutrients. Some might object to a Christmas card featuring a parasite. But wait ... the relationship may prove to be mutually beneficial.

Paintbrush is only partially parasitic; it can also photosynthesize (note green leaves). Sagebrush doesn’t appear to suffer much from this relationship unless conditions are harsh (especially drought). And in some cases, paintbrush provides benefits, like increasing nitrogen availability in poor soils. Finally, given the rate at which mutually-beneficial and even mandatory symbioses are being discovered—possibly the norm rather than the exception—further research may force us to rethink our story about paintbrush and sagebrush. They may represent the sharing spirit of Christmas after all.

Happy holidays and best wishes for the year to come!