About a month ago I decided to explore the extensive tracts of lodgepole forest at the far end of our valley that hug our main access road. At a glance this forest appears “mature”, thick with trees around 50-70′ tall. But start walking through the woods a different picture emerges. There are old logging roads and the understory is clear and easy to maneuver. Additionally there are a lot of smaller lodgepole cuts on the ground, indicating thinning took place sometime after the area was logged. An occasional large old “wolf” tree shows up, an indication of a tree that was forgotten. The stumps on the ground are well-rotted, most covered with lichen.

I was interested in when the Forest Service might have logged this area. It’s an extensive fairly flat plain above the river that feeds into steep terrain. I measured a variety of lodgepoles, using a tape to determine the circumference, then divided by pi (3.14) to get their diameter. I asked ChatGPT to give me a rough estimate of age based on the common diameter (10″-14″) with fairly uniform dominance. ChatGPT gave me a rough estimate of 60-100 years old depending upon slope, moisture, etc.

I estimated that this logging probably happened in the 1950s/early 1960s when extension logging was taking place in the Rocky Mountains during the post-WWII housing boom. I was wondering if after the logging lodgepole pines were first in succession. ChatGPT’s answer was interesting. “In much of the central Rockies, especially around Shoshone National Forest, lodgepole is often a disturbance-dominant species that can periodically take over huge areas for a century or more after fire or heavy logging.”

So what can look like a mature forest is really a relatively young forest, especially with the preceding thinning that occurred. If you look at Yellowstone lodgepole regeneration since the 1988 fires, those forests are extremely dense, sometimes called “dog-hair” forests because they are impossible to walk through. Over time, these forest will thin naturally. The Forest Service here did their own thinning as the trees grew after the logging, thus resembling a more mature forest, giving the remaining trees more space, moisture and light to grow. The Forest Service came back in at some point in this area and thinned, as evidenced by the smaller diameter trees on the ground. They do this so they can return later for another cut when the girth reaches the width they desire.

Another clue was the presence of Abies bifolia (Subalpine fir) which were around 22″ in diameter. Loggers don’t like to take these firs because they don’t supply structurally sound wood. Douglas firs and Subalpine firs regenerate more slowly, tolerate more shade, and will sometimes sit for years without much growth after a lodgepole release from logging or fire. As the old lodgepole die off, the forest will slowly become more mixed.

And another clue of the age when this forest was logged was the presence of old slash piles. These piles were deeply collapsed and soil-like, indicating in this dry climate these were probably 40-80 years old.

In an adjacent area closer to the creek, I saw well-rotted stumps of huge Douglas firs, a desirable tree for timber cut within the dominant lodgepole forest similar in size to the area described above. These Douglas firs were 22-32″ diameter, indicating trees that were up to 250 years old. These trees were probably established in the 1700s-1800s and selectively cut with the lodgepole filling in afterwards and then logged again.

Some concluding thoughts:

1. Although this might look like a mature forest, its not what a mature forest here would look like. The hillsides, which were not logged because of inaccessibility, are mostly douglas firs and with fire suppression of over 100 years, they are succumbing to disease and beetle kill, with massive trees dead on the ground.
2. I was really interested in what this forest might look like pre-contact before logging and fire suppression. Here’s what I took from this exercise of a pre-contact forest structure:
   • patches of mature open lodgepole
   • scattered huge Douglas-firs and Subalpine fires
   • intermittent aspen groves
   • grassy parks and benches
   • burned openings in various stages of regrowth
   • willow and wet meadow areas near water
   • with far more variation than today.

Additionally our volcanic soils and harsh climate all naturally would have prevented perfectly closed forests over huge areas for long periods.

Before Europeans, Sheep Eater Indians lived here. One small drainage has remnants of 5 wikiups in a small meadow. That drainage now is dominated by large douglas firs (too steep a terrain to log). Recent beetle activity has made the drainage almost impassable. But several years ago I accompanied an archeologist there. The wikiups were no longer standing, but judging by the age of the aspens they used for the structure, the wikiups were about 400 years old. There are no longer any aspens in this area. So this information provided a few more clues as to what these forests might have looked like.

Instead of modern deadfall tangles, native peoples were moving through a shifting patchwork of young dense stands, old open stands, low-intensity burn area, meadows, aspen parks and forests that were structurally diverse.

A few years ago I was on a backpack in the Wind Rivers eastern side. This drainage resembled what I might have seen 300 or 400 years ago. The forest was a diverse assemblage of White Bark pines, Douglas firs and spruce. With mostly mature trees, the forest was easy to walk through, and you could tell that natural low-intensity fires had moved through probably one hundred years ago. The understory was full of blueberries. The area was so enchanting, a magical find in our forests today. Above this remote drainage was a high ridge populated with White Bark pines, the majority of which were dead from beetle kill, an uncommon disease occurrence at 11,000 feet in the past.

When you look at a forest today, try to imagine what it might have been as an old-growth forest, forests that are so rare in today’s world.

Filed under: Pines, The Wild Excellence | Tagged: hiking, nature, sheep eater indians, Shoshone National Forest, travel, trees, Yellowstone National Park |