Tree-following in the Footsteps of Wyoming Botanists

Balsam poplar in Montana in August. Photo by Matt Lavin who writes: "Balsam popular is the most common poplar in montane riparian settings in western Montana."

Last week we had snow and bitter cold (-16ºF in town one morning). This weekend the snow is melting fast, turning roads and trails to slush and mud. So I decided not to visit my trees, an aspen and a balsam poplar, which I'm sure are as dormant as I feel these days. Oh spring, where art thou?!

Instead, I checked online to see where balsam poplar grows in our area. Although it's common nearby to the south in the mountains of Colorado, it occurs only sporadically in the mountains of southeast Wyoming.

SEINet search results for Populus balsamifera, displayed in Google Maps.

An online search of the Rocky Mountain Herbarium at the University of Wyoming produced four specimens from the area where my tree grows (see map above). All were collected by Cedric L. "Ted" Porter, including two with his wife Marjorie. Ted and Marjorie arrived in Laramie in 1929, traveling from Ohio in a Model T Ford. Ted had been hired as Botany Instructor and swim coach at the University of Wyoming. In 1937 he was promoted to Assistant Curator of the Rocky Mountain Herbarium, and then Curator when the great Aven Nelson, who started the herbarium in 1899, retired in 1943.

Porter served as Curator until 1968. During that time, the number of specimens grew by almost 50%, in part through Porter's collecting and trading of duplicates with other herbaria. His careful organized approach to curation made the Rocky Mountain Herbarium "probably the best organised, curated, and housed medium-sized herbarium in the nation" (Hartman & Nelson 2000. Cedric Lambert Porter (1905-2000) Taxon 49:577-580).

In 1962, Ted and Marjorie collected balsam poplar "at the Tie City Campground" in the Laramie Range. Here we enter the foggy slippery frustrating world of history. The Porters collected balsam poplar along a stream, but Tie City Campground is not on a stream, at least not today. Instead it's on a broad ridge crest, at a site some of us call Upper Tie City. Probably today's Pole Creek Campground was where the Porters collected. A stream runs along one side, and balsam poplars grow there, including the one I'm following.

Pole Creek Campground area in early January ... much warmer then!

It appears Ted and Marjorie were particularly interested in the balsam poplars because they made two collecting trips. The first was on June 1, when the trees were in late flower/early fruit. Below are images of their very nice specimen, showing young fruit with lobed stigmas. Like most poplars, balsam poplars are dioecious. This specimen is a female tree.

The Porters returned to Tie City Campground on July 26 and collected more material, this time to show the distinctive bicolored leaves (pale undersides).

Closeup of label; note habitat: "along stream."

It has been wonderful to get to know the Porters better, especially after hearing their names for 40+ years! And now when I visit I will be following ghosts as well as trees—something I enjoy very much.

This is my contribution to the gathering of tree followers kindly hosted by The Squirrelbasket. Want to give it a try? More info here.