Walking Tour

Welcome to Ravenna Park!

Ravenna Park is located just north of the University of Washington in the Seattle Ravenna neighborhood. It features a wooded ravine with various trails and sites to explore the natural history of the Seattle area. You can get to the park heading North bound on the I-5 and exiting at 65th street. It is also just a quick 15-20 minute walk from campus!

We will meet for our tour at the intersection of NE University Way and NE Ravenna Boulevard in Cowen Park (left side of map). This is where I usually enter the park for my weekly observations. Walk past the picnic area and playground and head towards the trail under the canopy of the Western Hemlock forest. 




1. Ecological Disturbances

Ravenna Park is a key area to observe the Western Hemlock Forest, however you will still see signs of ecological disturbances throughout in the form of invasive species. At this site you can see a huge overgrown English Holly bush also notice the English Ivy crawling across the forest floor and up the trees. These invasive species out compete native species growing rapidly and in wild abundance! Other invasive species to notice around the park include Horse Chestnut and Laurel. You will notice that there is usually not as much understory plants growing around the Horse Chestnut, this is because the non native plants change the makeup of chemicals in the soils they grow in so the less adaptable native plants cannot survive. Native species are important to the ecosystem because they maintain environmental balance within their own habitat. Invasive species travel by wind, pollination, and humans and affect native species by create competition for the resources in order for them to survive. In addition, invasive species usually grow taller than the native species and limit the amount of sunlight for them to obtain food. Furthermore, invasive species adapt faster in new environments, thus, causing competition for nutrients.

English Holly and Ivy

2. Plants
Ravenna Park is full of native plant species found in the Western Hemlock forest. The park is mostly forested with Big leaf Maple, Western Red Cedar, Douglas-fir, Red Alder, and Grand Fir.This is the site where I began noticing native plant species, and one of the places I come each week.  

The other notable plants in this area are the Sword Ferns that grow on the slope of the ravine. They are identifiable by their once cut leaflet and ability to persist year round. Try to notice the difference between sword and lady ferns. Lady Ferns are lighter green with a delicate lacy leaf pattern, they have thrice cut leaflets and grow back each spring. They are also more likely to be found near the water. 

Sword Fern

Lady Fern

3. Fungi


The fairy ring mushroom grows in clumps at this site. It is identifiable by the bump in the middle of the cup. The fairy ring mushroom fruiting season lasts between may and october yet the mycelium of the fungus remains underground throughout the year. As we learned from Noelle, the mushrooms will return in the same area year after year so we can return to this exact area to collect mushrooms next year. One way to cook the fairy ring mushroom is to sauté them in butter for about 5 minutes, add a generous squeeze of lemon juice and simmer for another 10 minutes. They are also know to add delicious flavor to sauces and stews. 

Button Mushroom

Fairy Ring Mushroom

Turkey Tail

 <http://www.mykoweb.com/EdibleMushrooms/recipes/FairyRing.html>.


4. Invertebrates.

Yellow faced bumblebee

Millipede

Pillbug

Next we will reach the site where I spent one afternoon looking for invertebrates. We head off the trail a little bit and sit down under a giant Western Red Cedar near the ravine. Look on the ground for movement in the soil and dead leaves. The invertebrates are small and very well camouflaged in this habitat. If you look closely enough you will see millipedes, darkling beetles, Crane flies and pillbugs crawling all around you. You may also see the Yellow faced Bumblebee pollinating flowers and digging through forest debris on the ground. Many of the invertebrates eat the dead wood on the ground.  Now look at the giant horse tails and lady ferns growing to your right. On the stems of the plants and underneath the leaves you can find California Prionus, Common Midge, Daddy Long-legs, Common Pillbugs, and beetles. At the edge of the ravine turn over stones to find Common Water Striders and Dragonflies. 

Carpenter Ant

California Prionus

Giant Crane Fly

Common Midge

Darkling Beetle

Daddy Long-leg

5. Ecological interaction Between Species

Artist's Fungus

We pause at this peculiar looking tree growing of the slope right next to our trail. The tree is a Douglas fir snag, a dead standing tree, the inside is hollow however the outside is covered with lichens and fungus. Most noticeable is the beautiful yet strange looking Artist's Fungus. Fungi are major decomposers, the only organisms that can digest the lignin in wood. They play a huge role in forest ecosystems and are often found attached to dead trees or on piles of dead wood. In addition, mycorrhiza fungi forms a symbiotic relationship by growing on the roots of trees and are found on 95 percent of all plants. Just a few steps beyond this tree we can see another visible interaction of species. This nurse log, the stump of a fallen tree is the home to species of Red Huckleberry, Licorice Fern and other mosses and lichen of the crustose and foliose variety. It provides moisture as it decays. It can also be seen as a sign of the age of the forest. 


6. Geology/Geomorphology 

The creek that runs through the park was created some 50,000 years ago when the Vashon Glacial Ice Sheet melted and formed Lake Russell which cut drainage ravines through new glacial fill. The Green Lake drainage basin continues to empty through the Ravenna ravine into Lake Washington although the creek has been made smaller today due to the outflow being diverted to sewer systems. Lake Russell disappeared when the ice sheet retreated north. The creek is the old overflow channel burst out from Green Lake. The raging water is what cut the ravine through the glacial sediments. Some of the glacial sediment layers found in Ravenna's ravine include till, sand and silt, and clays. There is also a lot of landslide debris in the ravine due to the slick layer of clay.  While walking through Ravenna the bubbling sound of the ravine is a constant companion and you can often look over and see it, although sometimes it is hidden by the trees and plants growing around it. One excellent spot to view the ravine in crossing a small wooden bridge directly over the water, it is here that we can also see the awe inspiring Ravenna Erratic. The Ravenna erratic is a giant boulder most likely carried on the Vashon ice sheet from the north and deposited at this site during the melting. It serves as another reminder of the natural history of the Puget sound region and its connection to the Cordilleran Ice Sheet. Growing on the erratic is a mosaic of different crustose lichens and fungi. 

Ravenna Erratic

7. Animal Behavior

Eastern Gray Squirrel

Yellow jacket Nest

As we continue to walk along the trail keep your eyes open for any animals. I couple of times I have caught glimpses of the Eastern Gray Squirrel. They are really fun to observe especially when there are a couple of them. I have watched them chasing each other up trees and generally scampering about looking for food. Sometimes you will only hear their harsh calls, I have mistaken them for birds a couple of times. We will stop and take a look at the tiny Anna's Hummingbird nest made of lichen and mosses located on the side of the trail in a laurel bush (non native). I have been coming back  to this spot frequently just to look and the small nest as see how its doing. Another nest in this area belongs to the Western Yellow jacket, I noticed a bunch of them swarming around the paper nest flying in and out. 




8. Land Use History 

What is now Ravenna park had been inhabited since the end of the last glacial period by the Native American Duwamish people until the arrival of white settlers in the 1800s. The Native Americans made great use of "the tree of life" or Western Red Cedar, digging out canoes and weaving cloth for the vertical strips of bark. Ravenna may seem like a forest paradise but it is still recovering from the logging craze beginning in the early 1900s and is only a fraction of the magnificent forest it once was. The forest is considered second growth rather than old growth like the forest we saw on the Olympic Peninsula. It has more Red Alders, nitrogen fixing trees and an abundance of young trees throughout. It lacks snags (dead standing trees), nurse logs, and understory trees that are more common identifiers of old growth. In the mid-1960s, the ravine was filled using freeway construction spoils. The plan was to use the ravine for staging a comprehensive storm water drainage piping project in 1986. This raised awareness for the neighborhoods of the watershed to protect and restore the park. At one point the creek was completely dried out and now it is only a trickle of what it once was in the early 1900s. Since 1991, the park has seen major restoration by residents of neighborhoods in collaboration with the City. At this site we see a fenced off area for the undisturbed growth of new Western Red Cedars as well as some other native species like Tall Oregon Grape. Throughout the park you can keep your eyes peeled for more restoration activities and even get involved and volunteer! 

9. Birds

Pass by the still water pond and continue on the small trail that looks a little less travelled. As you walk further into the wooded area you will notice a huge clump of Salmonberry bushes at this time of year the berries are huge, ripe, and delicious. In the bushes and trees around here I observed the greatest number of birds. It is easy to hear the birds all around you anywhere in the park but I was able to get very close to them at this site. Wait for a while, be patient and soon you will see some movement along with the songs. I have commonly observed American Robins, Song sparrows, Pacific Wren, and the Black-capped Chickadee in this area. You can also hear noisy American Crows squabbling  around here. Just the other day I was lucky enough to see the Spotted Towhee here. I identified it by the call sounding like meee meeee then saw another one responding a little further up in a Big Leaf Maple. You may also hear the strange sounds of the Pileated Woodpecker pecking the bark of a dead Douglas Fir. The sound caught me off guard at first until I saw the bird. When looking for the birds remember that patience is key. First listen for the call and try to determine what bird it is and where the sound is coming from. Then look in the branches of trees or places you would expect to find them. Unfortunately I did not have my own binoculars this quarter but definitely bring some if you have them, its a great way to physically identify birds based of their features and also these birds are gorgeous!

Pacific Wren

American Robin

Pileated Woodpecker

Spotted Towhee

photos from iNaturalist



10. View from Above

To end the walking tour we will make our way across the bridges in the park. This is a great spot to come and get a birds eye view of Ravenna Park. From this observation point you are at the same level as the canopy and can easily see the mix of Big leaf Maples, Red Alder, Western Red Cedars, and Douglas firs dominating the forest. This is also a reflective spot to look out again at the landscape of Ravenna. It is easy to see both slopes of the ravine from here and follow the pattern of the creek with you eyes. From here you can see birds landing in the higher branches of the trees and get a good look at the way they fly. When you look back down you can see some people walking their dogs or running, this is a good reminder of the importance of parks like Ravenna in the city and the need to experience nature on an innate level.