Outdoor Science Archives - Eva Varga

November 6, 20151

Foraging for Mushrooms: A Wild Edibles Nature Study @EvaVarga.netOne of the things I just love about the Oregon coast is the plethora of fungi. This past week, my daughter and I attended a Fall Mushrooms class at the interpretive center. It was a fabulous class whereby we learned to not only identify many of the local species but we also learned which are edible.

We spent the first couple of hours in the classroom engaged in a lecture format whereby the instructor began with an introduction to basic mycology. He walked through the life cycle of mushrooms and as well as the anatomy of a mature mushroom.

He also shared a slide presentation of the species we were likely to see. With each photograph, he discussed the species’ habitat preferences (in other words, where they were most likely to be found) and the typical time of year they were most prominent.


We then took a short break and proceeded down the trail for our foraging excursion. We didn’t find too many in the first half mile or so of the trail. Those we did find had begun to decay so we were beginning to get a little discouraged. Perhaps we were too late in the season?

We didn’t give in however, and our perseverance paid off. The group had begun to spread out and cheerful exclamations of “I found Chantrelles!” or “Wow! Look at the size of these!” could be heard in the near distance.


Here is a list of just a few of the species we found:

  • Hawk Wing
  • Chantrelle (illustrated above)
  • Velvet Bolete (illustrated above)
  • Beef Steak (pictured at top)
  • Pine Spike (illustrated above)
  • Oysters
  • False Chantrelle
  • Lobsters
  • Slippery Jack
  • Blue Polyphore
  • Coral
  • Toadstool (toxic)

Without doubt, the best mushroom text available is Mushrooms Demystified by David Arora. Published in 1986, it is an encyclopedia of mushroom facts and lore, lavishly illustrated with full-color photographs, literally everything you need to know about mushrooms, edible or not. Any botanical field guide should have is a good dichotomous key and Arora provides a very good key. The photos are excellent and the color plates are spectacular. This is a hefty volume, however, it is not the best for field identification.

The author has thereby released a field companion All That the Rain Promises and More: A Hip Pocket Guide to Western Mushrooms. This pocket-size book allows for quick and easy identification of common mushrooms. It also provides delicious recipes and stories of friends and funny anecdotes are sprinkled among hard facts.

Another favorite resource is the National Audubon Society Field Guide to North American Mushrooms. Organized visually, this book groups all mushrooms by color and shape to make identification simple and accurate in the field. With more than 700 mushrooms detailed with color photographs and text, this is a great guide for identification in the field.

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We’ve always enjoyed taking part in the monthly challenges at Handbook of Nature Study. This month, our selected challenge was Make a List.

May 2, 2015

Soil is the part of the ground where plants grow. Soil is a mixture of tiny particles of rock and rotting plant and animal material, with water and air between them. Soils help plants grow in two ways. First, soil holds the plants into place. Second, soil contains nutrients that plants need in order to survive. These nutrients include water, phosphorous, nitrogen, and potassium.

Over the course of the next few weeks, STEM Club will be investigating soil ecology as a part of the Year of Soils. I’ve shared a few of our past endeavors relating to soils here:

Soil Ecology Activities for Middle School

Cycles and Ecosystems {Free Printable}

Soils Support Urban Life: Rain Gardens & Composting

Soils Support Agriculture: Ideas to Integrate Writing

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Today, I share a lesson on soil horizons and particle size.

Soil Horizons

Soil particles vary greatly in size. The largest particles settle to the bottom first. The fine particles settle slowly; some are suspended indefinitely. The amount of open space between the particles has much to do with how easily water moves through the soil. This also determines how much water the soil will hold, which has a major effect on the type of plants that can grow in the soil.

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Things to look for in soil are color, texture, structure, depth, and pH. A general soil profile is made up of a litter layer, A horizon, B horizon and C horizon. A soil sampling device (pictured in the collage above) allows you to gather data on the soil makeup on any site.

Soil Particle Size

Soil scientists classify soil particles into sand, silt, and clay. Scientists use these three components and the calculated percentages on the texture triangle to determine the textural class of the soil at a given site.

A soil’s texture depends on the size of its particles and living things depend on the right texture to thrive in the soil. Every soil type is a mixture of sand (2mm – 0.05mm; feels gritty), silt (0.05 – 0.002mm; feels like flour), clay (Smaller than 0.002; feels sticky when wet), and organic matter. Squeeze some soil between your fingers. Is it crumbly? Sticky?

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net

Let’s Get Dirty ~ Terrestrial Soils

One of the best activities to engage kids in the study of soil ecology is the sample the soils around your home or school yard. Begin by asking the following questions:

1.  Are there different types of soil near your home?

2.  What texture class is this soil?

3.  What is the particle size make-up of this soil?

The answers generated prior to the investigation are part of your hypothesis. Record your ideas in your science notebook before you begin and give reasons. Why do you suppose the soil in your yard is predominately sand? What experience or prior knowledge do you have to help you make this statement?


  • 1 Soil probe
  • 1 Metric ruler
  • 1 Quart jar with lid
  • 1 Set index cards for diagrams


  1. Use the soil probe to collect soil cores as deep as possible from a predetermined site.
  2. Diagram and measure the depth of each layer or horizon in your sample.
  3. Fill the quart jar at least half and no more than two thirds full.
  4. Fill the rest of the jar with water, seal tightly and shake vigorously for 10 minutes. Let the jar stand for 24 hrs.
  5. The next day, mark the soil layers of each sample on an index card placed behind the bottle. Mark the top of the soil and the points where the layers change. Calculate the percent of sand, silt and clay in your sample. To do this, measure the following marks you made on the card: entire height, sand (bottom) layer, silt (middle) layer, and clay (top) layer. Then take the height of each layer by the total height and multiple by 100. Record the figures on the data sheet.

STEM Club: Let's Get Dirty (Soil Ecology) @EvaVarga.net
Analysis of Results

  1. At which site was the soil the most sandy? silty? mostly clay?
  2. Do you think that this is a trend and would be found at other sites? Explain.
  3. What are some factors that may change the results of this experiment? Explain.


  1. Did you achieve your hypothesis? Explain.
  2. What did you learn by doing this exercise?
  3. Do you think the soil will be the same at other sites (park, forest, meadow, near the shore of a lake or river, etc.)? Design an inquiry project to learn more.

May 24, 20144

Our STEM Club focus the past few months has been ecology and we recently concluded our three part Field, Forest, & Stream study. As a part of the forest ecology focus, we partnered with the USDA Forest Service to hear first hand how a forester manages a forest and to get a chance to use the real tools of the trade.

I met with the Forest Service staff a few weeks prior to our outing to discuss my goals for the lesson and to visit a couple of different study sites.  We were thereby able to choose the site best suited for the lesson and for our comfort.  Of the two sites we visited, one had experienced a severe forest fire about 10 years prior and though it was a great visual for forest succession (one of the topics we have been covering), there was little to no shade cover as it was still in the shrub stage.  We thereby selected a site nestled in a forested area on the McCloud Arm of Shasta Lake.

This post contains affiliate links.

forest ecology

Forest Ecology

From an ecological perspective, the definition of a forest includes all the living components of an area, from the trees to the bacteria, and along with the non-living physical factors, from the soil type to the microclimates. One of the goals of the Forest Service is to provide science-based research, instruction, and extension that supports forest and wildlife conservation and management in an ecologically, economically, and socially sustainable fashion.

Tools of the Trade

Upon our arrival, the foresters described the area (noting that plants on the north side of the peninsula were significantly different than on the south side) and instructed the kids in how to determine our pace for 100 feet, information the kids would need to determine the height of the trees.  They then demonstrated the use of a variety of tools – increment borer (to determine age and growth factors), clinometer (to calculate the height), and D-tape (to calculate the diameter of the tree at DBH or diameter at breast height).

forest data

The kids were then divided into groups and walked out to one of four trees that had been previously marked.  Using the tools described, the kids took a variety of measurements and used the data to calculate the approximate value of the selected trees. [The data from two of the trees is shown in the table above.]  What I loved was that the foresters discussed that the tree may be more significant to the health of the overall ecosystem than the monetary value. They then pointed out a tree that had a large number of acorns stashed into the bark by acorn woodpeckers; this was just one of many additional factors that foresters use to manage a forest.

If you would like to undertake a more in-depth forest ecology study, I highly recommend the Tree Study F.I.E.L.D. Kit® by Forestry Suppliers.  The complete kit includes a Tree Finder illustrated manual to determine species, a tangent height gauge and 50m measuring tape to figure heights, and a diameter tape. With these tools, students can study annual growth rings by extracting a core sample with a professional model 8″ increment borer (with 10 core holder cards).

Students can also determine the volume of wood in a tree by using the tree scale stick. The kit also includes biodegradable roll flagging and stake wire flags to delineate research areas. Six plastic handheld magnifiers, six packs of six tree cookies, 12″ ruler, lesson plans correlated with National Science Education Standards, and carrying case box are also included.

Interested in undertaking this study yourself? Field, Forest, & Stream is part of the Life Logic: Ecology Explorations unit that I have developed for middle school students. What better way to learn about ecology than to get out there, collect data, and experience the physical factors that influence the animal and plant communities first hand.

May 23, 20143

With our STEM Club, we recently undertook a three part ecology study I call, Field, Forest, & Stream.  We met at a local preserve with a fabulous outdoor classroom space and spent the day inundating ourselves in outdoor science. Today, I share with you the activities we enjoyed as a part of our stream ecology lesson. 

stream ecologyStream Ecology

Streams and their surrounding riparian areas provide essential habitat for a variety of fish and wildlife species. To maintain a healthy population of fish and wildlife, a habitat must provide food, water, cover from predators, breeding, nesting, and rearing areas, and protection from heat and cold.

Healthy riparian areas provide most or all of these elements for fish and wildlife species. “Riparian” means riverbank, and “riparian area” refers to the border of moist soils next to a body of water, and the plants that grown there. A small stream with steep banks could have a riparian area that is only a couple of feet wide, but a large lake in a broad valley could have one several hundred feet wide.

Stream Survey / Habitat Assessment

Many factors go into making up a riparian area that is healthy and meets the needs of a variety of species. The data we gathered as a part of our habitat assessment evaluates many of the key indicators of the condition of these important areas. Typically, an authentic riparian area habitat assessment evaluates eleven different parameters, we focused on just a few to simply gain field study experience.

stream data

Bottom Substrate

Substrate is the material that makes up the bottom of the stream. It can be a good indicator of land use activities and gradient upstream. It determines what types of macro invertebrates can live there and the suitability of the site for fish and spawning. A diversity of types and sizes of materials is considered to be better habitat than just fine materials such as silt and sand. The bottom substrate affects the characteristics of flow, the quality of the water, and the suitability of habitat for instream life.

Channel Shape

Channel shape can be an indicator of other forces at work in the steam and of conditions at other times of the year. Is the shape a natural product of stream forces, influenced by the actions of humans, or a combination of both?

Velocity of Current

Fast-flowing water is generally more turbulent than slow-moving water.  Turbulence is one factor that influences concentrations of dissolved oxygen.  Both fast and turbulent flow require different living strategies for organisms found in these reaches. To calculate the current velocity, we measured a 50ft distance along the shore. We then used a stopwatch to calculate the time it took an orange to float this distance. V=50ft/x sec.

Interested in undertaking this study yourself? Field, Forest, & Stream is part of the Life Logic: Ecology Explorations unit that I have developed for middle school students. What better way to learn about ecology than to get out there, collect data, and experience the physical factors that influence the animal and plant communities first hand.

April 20, 2014

With our STEM Club, we are undertaking a three part ecology study I call, Field, Forest, & Stream.  We met at a local preserve with a fabulous outdoor classroom space and spent the day inundating ourselves in outdoor science.

field ecology

Field Ecology

Our focus for this first visit was on field ecology and we looked at several characteristics:  soil, sunlight, water, plants, and animals.  We dug two holes: one in a disturbed area (the trail) and one in a grassy area. We were able to collect some great data (shared below) and even found an amazing spider-like critter in the hole the boys dug.

field data


We were able to identify the critter as a Solifugid (pictured in the collage), known variously as camel spiders, wind scorpions, or sun spiders. They are non-venomous, although they are capable of inflicting a painful bite with their powerful jaws.

Most live in dry climates and feed opportunistically on ground-dwelling arthropods and other small animals. Although Solifugae are considered to be endemic indicators of desert biomes, they occur widely in semi-desert and scrub. Some species also live in grassland or forest habitats. Solifugae generally inhabit warm and arid habitats, including virtually all warm deserts and scrublands.

The name Solifugae derives from Latin, and means “those that flee from the sun”. Can you guess why?

We then spent time looking for more critters and listing all the plants and animals we found.  Some of the kids actually made a list – some did not.  If you would like to see the list of plants & animals identified thus far, please let me know. I’d be happy to share it with you.

Interested in undertaking this study yourself? Field, Forest, & Stream is part of the Life Logic: Ecology Explorations unit that I have developed for middle school students. What better way to learn about ecology than to get out there, collect data, and experience the physical factors that influence the animal and plant communities first hand.

May 21, 20122

Yesterday, an annular eclipse of the sun was visible to the United States and a narrow path across the northern Hemisphere. We were delighted to have the opportunity to observe the eclipse – and even better – we did so with an awesome group of Letterboxers.

Featherhead with Green Tortuga as he gives a mini astronomy lesson

We met at Hog Plateau – an area inundated with letterboxes.  However, due to the heat (it was nearly 100 degrees), we opted to save the quest for another time.  Instead, we spent the evening exchanging signature stamps with our new Letterboxing friends, catching up with friends whom we had met previously, and seeking out the special event boxes – some hidden in plain site, others (travelers) required little sleuthing.

Featherhead with Lady Marmalade
A few of us observing the eclipse
Team Academia Celestia – Maersk, Makita, & Featherhead

Solar eclipses happen all over the globe all the time, but this was the first in the continental U.S. in more than 18 years.  An annular eclipse is a “ring of fire” solar eclipse. A total eclipse is when the moon’s shadow completely covers the sun and makes it dark during the day. This eclipse will cover about 85% of the sun leaving a visible ring.

Our dynamic host, Green Tortuga, captured this image of the eclipse through his telescope. Thanks again for putting this together for us.  It was a fabulous evening!