Hard snow

allows curious naturalists to extend their range

Hard snow in late January and early February made it easy to cruise around the forest on or off the regular trails. One could walk up the Thunder Mountain trail from DOT over the top of the nasty mudholes or prance without skis or snowshoes from Spaulding Meadow to the John Muir cabin. The low temperatures turned the snow to the hardness of concrete, in most places, so we could amble at will on our little explorations.

Well, in most places, yes. Except for the spot where the snow gave way completely and nearly pitched me into the adjacent river. One leg suddenly dropped into a hole, over knee deep, putting me right off balance. I was saved by a convenient, friendly alder that reached out a small branch in the nick of time.

We were walking along the lower part of the Herbert River, near its junction with Eagle River. The floodplain here is eroding badly and soon the Herbert will be shorter, joining the Eagle some distance upstream from the present confluence. Large trees have recently toppled into the water and lie waiting for spring floods to carry them toward the sea.

The fallen trees left steep cut-banks where the root masses had parted company with the floodplain. This exposed several horizontal layers of sediments of differing colors and textures: thin rust-colored layers of slightly coarser material were interspersed with wider, gray layers of very fine silt. These tell a story of variations in the flow of the river as the flood plain was built up. Roots had grown down through the layers, and the rust-color seemed to have followed along the course of the roots, perhaps leached by rain percolating downward and seeking the path of least resistance. Farther upstream, one can still see old river channels, now forested, where the river meandered before cutting its present channel. A lot of history is written in this landscape, for those who can read it.

Our wanderings frequently crossed those of peripatetic porcupines that had left their tracks when the snow was soft. There was evidence everywhere of porcupine lunches—spruce trunks with great gaps in the bark and porc-size tooth marks on the wood, neatly clipped spruce twigs dropped from the trees with the needles reduced to short stubs, even elderberry shrubs with gnawed-off shoots (despite their rank smell; apparently porcupines don’t care!).

Mink had scampered back and forth from forest edge to river, leaving numerous trackways now preserved in the crusty snow. Otter scat at the edge of the water showed the remains of a fish dinner. Of course, red squirrels had left their customary little piles of scales from alder cones and spruce cones as they extracted the seeds.

Another exploratory foray took us to a well-frozen wetland. As we meandered here and there, we noticed occasional beaver cuttings. Low-growing hemlock branches and small hemlock trees had been gnawed off and removed. Beaver teeth had scraped sizable patches of bark from standing hemlocks. A few shore pines and alders had been harvested, but hemlock was the clear favorite even though alders were quite abundant. This was interesting, because conifers are usually low-ranking choices for beavers. Alders are not a top choice either but are used in some regions. Their favorite trees are typically aspens, cottonwoods and willows, but these were not available here.

hemlock-midden-beaver-ck-KMH-Feb-2014
A hemlock midden. Photo by Katherine Hocker

We know that our local beavers sometimes cut hemlocks for use in construction, because we often see a branch or two incorporated in a dam. But the consistent use of hemlock for food seems unusual. There may be times of year when hemlock is more nutritious and palatable than at other seasons; such seasonal variation has been reported for pines and, accordingly, beavers in certain regions use pine seasonally. But why prefer hemlock to alder? As usual, we end up with questions!

The beaver lodge in this wetland did not have a winter cache of twigs and branches in front of it. But we found a midden a short distance away, where uneaten hemlock twigs had been removed from branches and stacked up in a pile, mixed with the de-barked branches. It is unusual, in our experience, to find accumulated remains of beaver lunches in middens like this one.

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