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Our Dynamic Forest

By Bruce Rottink, Volunteer Nature Guide & Retired Research Forester

 

This year January brought us an unusually wet, heavy snow.  In my Lake Oswego backyard, it amounted to just over 7-1/2 inches of the white stuff.  The snow at Tryon Creek State Natural Area (TCSNA) was roughly similar.  As with so many other unusual events, it was a great opportunity to learn more about our forest.

 

The wet, heavy snow brought many changes.  Some that we humans, entranced with the visual wonder that is our forest, tend to regard as tragic.  But Nature may have a different view.  Let’s take a look at some of the things that happened.

 

Look out below! 

All kinds of trees fell down.  As shown in the photo below, the top snapped off from this red alder (Alnus rubra) growing near Red Fox Bridge.  You can see the top lying on the ground.  For the alder, this is a horrific setback, if not death.

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Top of alder broken off near Red Fox Bridge.

 

However, the plants growing on the ground under this alder may have a different perspective.  I stood right over the alder trunk lying on the ground, pointed my camera upwards and took this picture of a significant hole in the canopy.

Photo 2

View of the sky where the alder fell down.

 

Do you suppose the plants growing on the ground are looking up and thinking, “Oh what a tragedy.  Now we’re going to be growing in full, life-giving sunlight, and we won’t have competition from the alder.”  No matter what kind of tragedy it was for the tree that fell down, many of the neighboring plants will be celebrating because of the extra sunlight they will be receiving.

 

And if the existing plants already on the ground aren’t able to jump in and take advantage of the newly sunny spot, rest assured that some new plants will.  The photo below shows numerous red alder seeds (two are marked with red arrows) on the Middle Creek Trail the very same day I photographed the broken alder.  Finding these tiny seeds in the forested area would be very difficult, but have no doubt, they are there!

Photo 3

Red alder seeds on the trail (green Douglas-fir needle at bottom provides perspective).

 

Death Cleanses the Forest

Perhaps you mourn the loss of so many good trees.  In at least some cases, your tears are wasted.  A storm like the one we had can be viewed in part as Nature cleaning up the forest.  For example, as part of a human cleanup effort, I spent some time cutting through the trunk of a western redcedar (Thuja plicata) that was lying across the Cedar Trail so the trail would become passable (see photo below).

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Western redcedar stem lying across the trail (note pen for scale).

 

It was sad because it was a young tree, with potential to become one of the esteemed elders of the forest.  Or so I thought.  As I dragged some of the branches off the trail, I noticed the top of this tree (pictured below).

Photo 5

Dead top of the fallen western redcedar tree.

 

The top four to five feet of this tree had already been dead for some time.  So the real story was that this tree was already having problems of one kind or another, and the storm just ended its struggle.  Since it already had a dead top, its long term potential was not as great as I originally thought.

 

In another case, a very tall (about 115 foot) Douglas-fir (Pseudotsuga menziesii) fell down across the Old Main Trail.  This is another tree that I cleared off the trail (Note:  The clean-up work I did after the storm proved very educational.  You might want to give it a try!)  The top was forked due to some damage many years ago, as indicated in the picture below.

Photo 6

Fork-topped Douglas-fir on the ground after a heavy snowstorm.

 

But this is another example of a tree that was already in trouble.  The smaller branch on the right side of the picture shown above had been damaged many years before this year’s storm, as you can see below.

Photo 7

Broken, semi-rotten top end of one of the major stems on a Douglas-fir.

 

I sawed off the top 12” of this stub, and inserted a pencil into the soft rotten area in the center of the stem.  The results are shown below.

Photo 8

Pencil stuck in stub of tree trunk.

 

Photo 9

This is how far I could stick the pencil in.

 

I could easily stick the pencil a couple inches into the rotten wood.  I cut 2 more feet off the end of this stub, and was still able to stick the pencil about ½” into the rotten center of the branch.  Once the fungus gains this much of a foothold in a tree, it’s only a matter of time before it seriously weakens the tree.

So once again, the storm felled a tree that was already in trouble.

 

Dead Trees Can be Useful

And if you mourn for the dying trees, rest assured that not all of the forest inhabitants share your grief.  Bark beetles lay eggs under the bark, and their larvae start burrowing through and eating the soft nutritious tissues that are right under the bark.  Of the hundreds of species of bark beetles, at least some attack after the tree is dead.  These beetles leave the kind of tracks like those you can see after the bark has been removed from this branch collected at TCSNA.

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Tracks left by bark beetles eating the soft tissues of the branches.

 

And of course, once insects get into a tree, can woodpeckers be far behind?  The photo below shows a heavily “wood-peckered” long-dead tree along Old Main Trail.

Photo 11

Heavily woodpecker-ed dead tree along Old Main Trail.

 

And Some Weird Stuff…

The snow also brought at least one unique observational opportunity!  Down near the creek in one area, I noticed that the snow had patches of yellow color.  (No, it’s not THAT!)  There were no animal tracks in this area, so I seriously doubt the yellow patches were from dogs or coyotes.  According to reports on the internet, yellow snow in this context is frequently the result of pollen getting mixed in with the snow.  Sadly, I got a picture, but never collected a snow sample for microscopic examination.  The storm was roughly at the time that some hazel (Corylus spp.) would be shedding its pollen, but I have no proof that’s what it is.

Photo 12

Yellow patches of pollen (?) on fresh snow near Beaver Bridge.

 

Assuming this is pollen, I have no doubt that pollen is shed like this on the ground every year.  However, it takes a snow covered forest floor before we will ever notice it.

 

Our Ever Changing Forest

Our forest is an ever changing ecosystem.  If we could see this forest in 400 years, much of it would look unfamiliar.  Most often the change is very slow, but a catastrophic event like a dramatic storm puts the changes in a time context we humans can relate to.  Enjoy our forest today, because when you come back tomorrow, it will be different.

 

 

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Native American Uses of the Forest

By Bruce Rottink, Volunteer Nature Guide and Retired Research Forester

 

For thousands of years before settlers from the eastern United States or Europe arrived in the vicinity of what is now Tryon Creek State Natural Area (TCSNA), Native Americans called this forest home. The Native Americans used resources ranging from rocks to trees to animals. However, the basis for much of the Native American life was the plant life of this area. They relied on the forest and waterways for everything; food, medicine, tools, clothes, everything!

What kinds of plants did they eat?

There were lots of plants and fruits the Native Americans ate. Some of the more tasty items were the berries from the forest, like the salal (Gaultheria shallon) berries. Pictured below are the plant and berries. I’ve planted salal in my front yard, and they are delicious on my morning cereal!

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Salal plant, with salal berries in the inset at lower left

 

Another food the Native Americans sometimes ate were the berries of the Oregon grape (Mahonia nervosa). In the photo below, the blue-colored berries are almost ready to eat, while the greenish ones have a way to go before they are ripe.

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Oregon grape berries starting to ripen

 

I’ve tasted Oregon grape berries too. My taste buds’ response was, o-o-o-o-kay! I think they’re about half way between yummy and yucky. According to ethnobotanists, people who study how different groups of people use plants, the Native Americans would sometimes mash the fruits of the salal and Oregon grape together. In this way, they had a greater total quantity of food, which still tasted “kind of” good.

 

Another category of food plants is represented by the skunk cabbage (Lysichitum americanus) pictured below. This plant has a large underground tuber (note: potatoes are also tubers). Unfortunately, the skunk cabbage tuber tastes awful. It had to be specially prepared to become even edible. Ethnobotanists refer to this as a “starvation food” meaning that you only ate it when the alternative was starvation. If you’ve ever smelled a skunk cabbage in the spring, you understand why it wouldn’t necessarily pop into your mind as a good food item!

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Skunk cabbage plant and flower

What kind of medicine is in the forest?

For the Native Americans, the forest was their drugstore. Just one of the many medicinal plants used by some Native Americans was the licorice fern (Polypodium glycyrrhiza). The pictures below show the licorice fern growing on the side of a tree at TCSNA and the second photo shows a cleaned-up licorice fern plant that was growing on a branch that was blown down during a windstorm. The rhizome can be thought of as a perennial stem, while the leaves come and go with the seasons.

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Licorice fern growing on a tree trunk

 

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Licorice fern after removing the surrounding moss

 

The Native Americans cleaned up the rhizome of the licorice fern and chewed it as a cough and sore throat remedy. Once when I was not at TCSNA, I cleaned up a licorice fern rhizome and chewed it a bit. It does taste faintly like licorice. Within 30 seconds of starting to chew the rhizome, I got a tingle right in the back of my throat. Although I was perfectly healthy at the time, the fern was definitely affecting me. It would have been interesting to see the effect if I’d had a cold or sore throat.

 

What kind of tools did they find in the forest?

One of the tools the Native Americans found in the forest was the horsetail (Equisetum spp.), pictured below. This primitive plant contains a lot of silica crystals. Silica is the most common material found in sand. The Native Americans used this as a “natural sandpaper” for finishing their wooden tools. The effectiveness of this tool can be demonstrated by using it to polish a penny.

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Equisetum and polishing a penny with Equisetum

 

The effectiveness of polishing is shown in the “before and after” photos below.

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Two unpolished pennies (left)        Far right polished for 2 min. with Equisetum.

 

What kind of clothes did they make from forest plants?

The western redcedar tree (Thuja plicata) had many uses. To give just one example, its bark is very fibrous. With careful harvesting and care it can be used to produce everything from rope to clothes. Pictured below is a cedar bark rain hat. These were widely made and used by the Native Americans on the Pacific coast. According to some sources, they would sometimes treat this hat with pitch to make it even more water repellent.

 

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Native American cedar bark rain hat

 

But of all the clothing that the Native Americans made from forest plants, the one that always intrigued me was that they used moss for baby diapers. I wondered how well those would work. Strictly as a public service, I decided to run an experiment and find out.

You personally tested moss as diapers? Seriously?

Before your imagination runs wild (it may already be too late), let me explain. I took samples of five water-absorbing things:

  • A major brand of modern disposable diaper
  • A sponge
  • A pile of moss
  • A traditional cloth diaper
  • A bunch of paper towels

 

I weighed each item dry, making sure I had between 60 grams and 90 grams of each material (this is about 2 to 3 ounces). I then soaked each item (separately) in water completely covering the test material with water for 15 minutes. Then I put each material on a sheet of screen to drain. When the drops of water falling out of the material were 10 or more seconds apart, I considered the material to be completely drained. I then weighed each item wet. I calculated “absorbency” by dividing the weight of water absorbed by the dry weight of the material.

 

The results are displayed in the chart below.

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Modern diapers with their SAP (Super Absorbent Polymer) ingredient can absorb more than 80 times their weight in liquid! But let’s cut to the chase. I was fascinated to see that moss, the key ingredient in the Native American diaper could absorb 7.4 times its dry weight in water. In contrast, a classic 100% cotton, all-cloth diaper can only absorb 3.5 times its own dry weight in water. So the Native Americans were using the superior diapering material! Wow!

 

At home in the forest!

To the Native Americans, the forest was their home, their grocery store, their pharmacy, their hardware store, their everything! They adapted to their environment to meet all their needs.

 

Master Recycler

Mother Nature: Master Recycler

By Bruce Rottink, Volunteer Nature Guide and Retired Research Forester

 

Recycling has become a “big deal” for humans in the years since I was born! As a kid, I remember burning newspapers in the burn-barrel by our garden, and throwing a massive number of tin cans in the garbage which doubtless wound up in some landfill. Now, the Oregon Department of Environmental Quality (DEQ) proudly reports that in 2013, Oregonians recycled 53.9% of our post-consumer waste. Nice try, but we don’t even come close to Mother Nature’s record of recycling: 100%!

Here at Tryon Creek State Natural Area (TCSNA) the forest constantly recycles biomass like leaves, logs and dead animals. Sometimes it’s fast, and sometimes it’s slow, but it’s always thorough!

We need look no further than some of the TCSNA’s old logs and stumps to see that sometimes recycling takes quite a while. This rotting log is approximately 18” in diameter. It is on the side of Old Main Trail and hasn’t changed much in the last 5 years, and I don’t expect it to completely disintegrate any time soon. In fact, research foresters report that fallen Douglas-fir (Pseudotsuga menziesii) logs sometimes take almost 200 years to completely decay!

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This might even be here for over another 100 years!

 

But other stuff “recycles” faster, doesn’t it?

Absolutely! In order to see how fast things are recycling (“decaying”) at TCSNA, I set up a small study. Scientists who want to study recycling in the forest often use things called “litter bags.” (The term “litter” here refers to the fallen leaves, twigs and branches on the ground, not to candy wrappers and used Kleenex!) I collected the plant material for this study off the ground, so this material was ready to start decaying.

I cut square pieces of window screen to make my bags. I placed the plant material on half of each piece of screen, and then folded the other half over the top, and stapled it shut. I fastened each bag to the ground using four big nails, one in each corner. I set up the bags in an area of TCSNA where they wouldn’t be disturbed. I put out some bags on September 11 and others on September 13, 2014.

In each bag, I put one of five things; Alder (Alnus rubra) leaves, bigleaf maple (Acer macrophyllum) leaves, western redcedar (Thuja plicata) twigs with their green scaly leaves, Douglas-fir twigs with needles, and finally, the scales from a Douglas-fir cone. I had two bags of each type of material. Then I fastened the bags to the ground.

 

So what happened?

This is what it looked like on September 13, 2014, after the full study was installed. You can see some of the green leaves inside the bags.

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Litter bags fastened down on the forest floor.

I took pictures of every bag each month. When I took pictures I brushed off the top of the bag, loosened two of the nails holding it to the ground, and slipped a piece of white plastic underneath the bag to provide contrast to the material inside the bag. I refastened the bags and replaced the litter following each photo. Below are some highlights.

By October 3, 2014 some natural forest litter had fallen on the bags. This is totally realistic. There were times when the litter bags were almost completely covered with natural litter from the trees.

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The litter bags after 20 days in the forest.

Having the litter inside bags did create a certain amount of unrealism. This point was made dramatically during my March 2015 visit to the litter bags, when the little critter pictured below was crawling over them. To the extent that snails might accelerate litter decomposition, my study was only an approximation of reality.

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This snail will never get at the litter in my litter bags. Sorry, little guy!

 

So let’s see the decay process!

The decay rates for the samples in my litter bags varied a lot between species, and sometimes between particular leaves of the same species.

 

Red Alder

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Alder leaves on Sept. 11, 2014 “Day 0”

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Alder leaves on November 26, 2014

 

 

 

 

 

 

 

 

 

 

 

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Alder leaves on March 28, 2015

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Alder leaves on Sept 27, 2015

 

 

 

 

 

 

 

 

 

 

 

The alder leaves decayed dramatically over the course of a year. After 79 days, the leaves had lost their color, but had only just started to disintegrate. By the end of March, the leaf in the upper half of the photos was pretty much reduced to the mid-rib (the tough “vein” going from the base of the leaf right through to the tip) and the lateral veins. In contrast, the leaf in the lower right hand corner still had a lot of the leaf blade left.

 

Bigleaf Maple

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Maple leaves on Sept. 11, 2014 “Day 0”

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Maple leaves on November 26, 2014

 

 

 

 

 

 

 

 

 

 

 

 

 

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Maple leaves on March 28, 2015

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Maple leaves on Sept 27, 2015

 

 

 

 

 

 

 

 

 

 

 

Once again, the maple leaves were significantly decayed after the first year, but the petiole (the stalk that attaches the leaf to the branch) being more “woody” than the leaf blade is still largely intact.

 

Western Redcedar

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Western redcedar on Sept 11, 2014 “Day 0”

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Western redcedar on November 26, 2014

 

 

 

 

 

 

 

 

 

 

 

 

 

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Western redcedar on March 28, 2015

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Western redcedar on Sept 27, 2015

 

 

 

 

 

 

 

 

 

 

 

 

Western redcedar is loaded with hydrocarbon molecules that impart decay resistance. The most amazing thing was that in November 2015, after more than two months on the ground, most of the redcedar branch was still green! (Confession time: The other redcedar branch had turned completely brown at this point.) After over a year on the forest floor, this branch, and its needles, was still largely intact.

Douglas-fir twig

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Douglas-fir on Sept 13, 2014 “Day 0”

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Douglas-fir on November 26, 2014

 

 

 

 

 

 

 

 

 

 

 

 

 

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Douglas-fir on March 28, 2015

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Douglas-fir on Sept 27, 2015

 

 

 

 

 

 

 

 

 

 

 

 

Unlike the alder and maple samples, this bag includes the woody twig in addition to the foliage. The Douglas-fir twig rapidly shed all its needles, producing an un-photogenic combination of a bare twig, and clumps of dead needles. The slight movement of the bags in preparation for taking photos is what caused the needles to gather in clumps. The needles, though brown and scattered, are individually maintaining their structural integrity. As with the western redcedar discussed earlier, the presence of hydrocarbon molecules in the needles and stem are helping resist decay.

 

Douglas-fir cone scales

The Douglas-fir cone scales are tough and woody. To tell the story of their decay in the first year, we only need two photos. In the 12+ months in the litter bag, there was no perceptible change in the Douglas-fir cone scales, except they are now slightly darker! Again, shifting the bag for photos results in shifting the scales around within the bag.

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Douglas-fir cone scales, Sept 13, 2014 “Day 0”

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Douglas-fir cone scales, Sept 27, 2015

 

 

 

 

 

 

 

 

 

 

The Cycle: Life > Death > Life

As organic matter decays, important chemicals like nitrogen and phosphorus are slowly released to soil for growing plants. The partially decayed organic matter in the soil dramatically increases its moisture holding capacity, and water infiltration rates, among other things. Better than most of us, Mother Nature knows that the rotting leaves and stems of today are the key to the towering trees of tomorrow! Without recycling, there would be no forest as we know it.

 

 

 

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