Wednesday, May 30, 2018

The Aspen Mission


Day 229: This is the first installment in the saga of Team Biota's May 29 field trip. There will be several more forthcoming.

Until yesterday, there had been no official record of Populus tremuloides (Quaking Aspen) within the Park boundaries. Plant Ecologist Arnie Peterson had received a report and photos from a member of the Owl Crew, but with anything of this nature, the plant's presence needed to be verified and herbarium specimens needed to be collected. Arnie provided Joe Dreimiller and I with coordinates for the site and off we went.

It didn't look like a place where you'd expect Aspens to grow, and indeed the 41 specimens we identified and flagged looked like they'd been struggling for many years just to reach a height of thirty inches (the tallest), but there was no doubt that they were P. tremuloides: stunted, but definitely Aspen. Any obviously live growth (fresh foliage) occurred on stems no larger than my little finger. However in many cases, multiple shoots were observed emerging from a thicker (1.5") woody base, often with the dead wood of former growth attached to it. All but three specimens occurred in a narrow swale approximately 10' x 100', in thin soil over rock better suited to moss and lichen. With such a small population in a very localized area, we couldn't reasonably remove an herbarium specimen roots and all, so three twigs were taken, sufficient to document the species.

Arnie, Joe and I are baffled by the presence of these trees. How did they get here? They're too far from any known Aspen population for a seed to have been excreted by a bird, although I believe that there could be a slim chance that one might have been caught in feathers. Likewise, although elk enjoy the occasional snack of Aspen, the same distance limitation applies. We searched for a larger parent tree, but found nothing. It is, as they say, a puzzlement, but Team Biota is on the case!

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