Welcome to Ravenna Park!
 |
| Figure 1, Google map |
After spending a quarter here observing plants, birds, insects, and all kinds of changes in nature, I want to introduce this amazing park to every nature-lover. Ravenna park is located north of the University of Washington. As shown in Figure 1, if you walk from UW campus, go directly north on 20th Ave, you will get there after 20 - 30 minutes. Even though the west side of Ravenna park is pretty close to Interstate 5, this whole park is still a quiet, close-to-nature place for hiking, barbecuing, jogging, bird-watching and so on. Now, I'm going to divide this online walking tour into 10 parts, each of which is a separate station with a distinct characteristic.
Station 1: Geology
Figure 3, an erratic rock in Ravenna Park
|
|
To find station 1, you need to follow the main trail all the way north to the point where my red "A" in Figure 2 is. There will be an four-way intersection. If you turn left there and walk along the trail a little bit, you will find the enormous erratic rock. Figure 2 was taken by myself at an erratic rock in Ravenna park. This place is also my natural spot where I've spent and will continue spending many weeks in observing birds, plants, phenological changes, and so on. Nevertheless, this place, especially this rock, is known for its geological history. 14,000 years ago, as a part of the Cordilleran ice sheet, the Vashon ice sheet, came down to Puget Sound area, which was part of the Salish Sea back then. As the Vashon ice sheet advanced, it brought all kinds of sediments with it from the north. As Figure 2 shows, the tip of the big ice sheet advanced into Puget Sound area. This tip was called Puget Lobe. When it began to melt and retreat at about 12,000 years ago, it left those sediments at Puget Sound area. This erratic rock is one example of them.
Station 2: land-use history
 |
| Figure 4 |
 |
| Figure 5 |
Located just a little bit north of the ballpark, my station 2, land-use history station, shows a lot of history you need to know about Ravenna Park, especially the impact of human beings on Ravenna Creek. As shown in Figure 4 as letter "B", if you walk pass the ballpark, you will quickly find the station. At this place, you can not only read the poster of Ravenna Park's history but also listen to the trickling Ravenna Creek. When you read the history poster, you will find out how this creek was damaged by human development in the past and how people realized the problem and improved it by doing restoration project. In 1911, in order to make some more space for people around Green Lake, the water level was lowered by human beings. Thus, they cut the connection between Green Lake and the upper part of Ravenna Creek, causing the upper part of Ravenna Creek to dry out. Also, in 1916, to create the ship canal for business, human beings built Ballard Lock, Monlake Cut, and so on. By doing this, they lowered the water level of Lake Washington. As a result, the connection between the lower part of Ravenna Creek and Lake Washington was cut. It is true that human beings caused a lot of damages to the natural environment in Ravenna Park. However, they realized their mistakes and they tried to improve the environment after that. Local communities gathered together and started a project called "Ravenna Creek Daylighting Project", and they ended up reconnecting Ravenna Creek and Lake Washington in 2006. Ravenna Creek. This whole story of Ravenna Creek is an good example showing that human beings can realize their mistakes and make the natural environment better.
Station 3: birds
 |
| Figure 6, station 3 |
 |
| Figure 7, black-capped chickadees' nest |
 |
| Figure 8, a steller's jay. Not in Ravenna Park, but it is the same bird |
Steller's jay preening its feather
There is a place in Ravenna Park that should be called birds station. You can find its location, shown as letter "C", in Figure 6. At least two different species of birds often show up at this location. To get to this place, you just follow the main trail , walking all the way to the erratic rock. When you see the lane to the erratic rock on either side of you (depending on which way are you coming from), you are in the birds station! The first bird species that I want to talk about is black-capped chickadee. Visually, the best way to identify a black-capped chickadee is to look for its all-black cap, like its name suggested. The bib is also black, which makes it easier to identify too. On a Saturday or Sunday, I went to Ravenna Park for my weekly journal. When I was trying to identify some unknown flowers, I heard that familiar sound "chick-dee-dee-dee-dee", which is the best way to identify it by ear. I looked up but I couldn't find it until a tiny litter head popped up from a small hole in this snag, as shown in Figure 6. Again, "chick-dee-dee-dee-dee". I was wondering if it was feed its babies inside the hole. I couldn't tell if they were actually in the hole or not since I didn't hear any voice from inside the hole. My guess was that the "chick-dee-dee-dee-dee"s were the warning calls the chickadee'd given to its babies, to alarm them about my existence and not make any noise. The second bird is a steller's jay, which is my favorite bird ever. The first bird I saw after I started bird-watching was a steller's jay. With a black crest and blue feather, it is the most beautiful bird for me (note that the bird feather is due to refraction light. They are actually black/grey). Then, after seeing that pretty bird, I got into bird-watching. At this birds station, there is a creek nearby. It is actually the Ravenna Creek, which flows all the way to the Union Bay Natural Area, another good place for birding. Oftentimes I saw a steller's jay come down here and drink some water and preen its body after its body gets wet. I remember preening is good for flight efficiency and plumage display. If a bird's feather is wet, it will be hard for it to maintain its flight position and speed. Also, the extra water will increase its weight and make it harder to fly. Every time I came across this bird, I wanted to take a better look at it. However, it always stayed in the low shrubs near the creek. So, it was pretty hard to take a decent photo of this pretty bird.
Station 4: plants
 |
Figure 9
|
 |
Figure 10, station 4
|
 |
| Figure 11, a red alder growing right by the creek |
 |
| Figure 12, red alder's leaves |
 |
| Figure 13, beaked hazelnut |
 |
Figure 14, salmonberries
|
 |
| Figure 15, something I can't ID, but stingy |
 |
| Figure 16, the underside of the leaves of that stingy plant. So scary...... |
This is place surrounded by many different kinds of plant species. For visitors, if you walk along the main trail, it's impossible to miss it. It's the letter "D" in Figure 9. The first kind of plants I want to introduce is red alder. Since Ravenna Creek run through this station, the wet environment here is perfect for plants like red alder. In Figure 11, you can see the red alder growing right by the creek to take advantage of this wet condition. There are two things you might want to keep in mind when you want to identify a red alder. First, red alders usually, though not always, have some white spots on their smooth barks. Second, their leaves are doubly-surrated and not hairy at all. I was having a hard time differentiating red alders' leaves and beaked hazelnuts' leaves. Even though they look pretty much the same, the beaked hazelnuts' leaves are hairy. As shown in Figure 13, beaked hazelnuts also grow at this station. It's a perfect spot for someone who has a difficult time telling those two species apart. Most beaked hazelnuts' leaves have tips that are like birds bill, another important characteristic of beaked hazelnuts. Another kind of plants that is growing here is salmonberry. As shown in Figure 14, those salmonberries have three-compound leaves. You can also see those berries! However, it seems like the berries are not edible yet. So, you might want to wait for a week or so to eat them. The last plant species I want to introduce is something I don't know yet. Hopefully, I will learn this one tomorrow since I am still waiting for someone to help me to identify it. This five-or-seven lobed shrub-like plant is not friendly. It has spines on its leaves! More amazingly, on both side! I made a mistake touch it before I saw those spines. So, I suggest you to be careful about it.
Station 5: invertebrates
 |
| Figure 17, station 5 |
Yellow-faced bumble bee searching for home
 |
| Figure 18, station 5 |
 |
| Figure 19, an earthworm |
 |
| Figure 20, some kind of spider |
This invertebrates station is the almost the same place as station 1. You can also find letter "E" in Figure 17. In Figure 18, the rock on the left is that enormous erratic rock. Since this station is right by Ravenna Creek, insects, worms, spiders and all kinds of invertebrates like hanging out here. If you dig out some soil, you will find a lot of invertebrates hidden in the mud. For example, I once found an yellow-faced bumble bee entering into its hole right here. As shown in the video above, this yellow-faced bumble bee acted like it lost its home. It was crawling on the ground and trying to find the entrance. It seemed like it forgot where its home was. Fortunately, it found it finally and entered in it. Even though the they are called yellow-faced bumble bees, they also have a yellow stripe on the tips of their abdomens. They are some of those important pollinators in Wahington state. On the other day when I came here to do my homework, I found an earthworm after digging some mud. I put it on that big erratic rock so that I could observe it. The earthworm didn't move a lot, except its head was wiggling back and forth. I didn't want to kill it, so I put it back to the mud. After that, I couldn't find it anymore. I also saw a spider a week ago. At that time, since the spider moved super fast, I had to use a bottle lid to catch it first and then observed it. However, that spider seemed to have an ability to escape from everything. I lost it after I took some photos. If you zoom in my picture, you will find the spider has four pair of legs, with the second pair being the longest. Also, it has some white stripes on its abdomen.
Station 6: a fungus
 |
| Figure 21, station 6 |
 |
| Figure 22, artist's conk |
 |
Figure 23, white undersides of artist's conks
 |
| Figure 24, a closer view of this artist's conk |
|
If you want to find my station 6, just walk along the main trail and look for some fallen branches on your left. There will also be a bigleaf maple standing right by those branches. The approximate location for this station is shown in Figure 21. So, if you can't find it by looking for fallen branches and that bigleaf maple, you could use this map this navigate yourselves. Looking for the red letter "F" on this map. One amazing type of fungi here is called artist's conk or artist's bracket. When you are walking on the trail, looking for something like those woody disks shown in Figure 22. As you can probably see, there are many rings on their surfaces. Since they are perennial conks, they will grow every year. Thus, people can count how old they are by reading those rings. Most of them are brown and have white margins around. However, those white margins are actually not just margins. They are connected to the undersides of artist's conks. If you take a look at Figure 23, you will find out how white and beautiful those undersides are. The white underside is the reason why this kind of fungus is called artist's conk. You can draw pictures on the "canvas" just like an artist! If you use you fingers to scratch and draw pictures, the white will be replaced by brown at every place your fingers touch. As beautiful as artist's conks look, they are harmful to plants when they are stuck into plants. In this station, those artist's conks will eventually cause the bigleaf maple to decay. However, if you do see some artist's conks stuck in tree trunks, don't bother to destroy them. First, when you can see them they've already infected the trees. So, destroying them won't do any good. Second, they are the ones who make the whole process of succession a lot easier. After infected trees die, they will create more space for other species of trees. In this case, the death of this bigleaf maple might create opportunity for climax species western hemlocks to grow. Also, fallen trunks can serve as nurse logs, which are beneficial for some many species. So, artist's conks are not totally harmful to a forest.
Station 7: a visible ecological interaction between species
 |
| Figure 25, my station 7 |
 |
| Figure 26, shade-tolerant western hemlock is waiting under bigleaf maple |
 |
Figure 27, a western hemlock has grown above the bigleaf maples
|
 |
Figure 28, a feature of western hemlock, tipping top!
|
My station 7 is a little bit hard to find. As the map shows, you have to walk on the trail left to the tennis court first. Then, while you are walking, look for some woody stars that go all the way down to the creek. When you see them, you are probably at the right place. Remember, never go down if you haven't seen the stairs. First, those slopes are dangerous. Second, you probably haven't got to the right place yet. Anyway, when you see the stairs, walk down a little bit. Then, look up! This is an great real-world example for forest succession. As shown in Figure 26, a western hemlock is growing under the shade of several bigleaf maple. But how could the hemlock only need a little sunlight to grow? Would that be enough? The answer is yes. Western hemlocks are shade-tolerant plants, which means they can grow under the shade of others species. Since they can live very long, as time goes by, they will take over the forest after other plants die. That's why they are called climax species. You can notice the succession in Figure 27. In this image, the hemlock has already grown taller than those bigleaf maples around it. Eventually, they will dominate this area. In fact, hemlocks don't only compete with bigleaf maples, but they also compete with other trees such as Douglas fir. Finally, I want to introduce some methods to identify western hemlocks, in case you confuse them with other species as I did before. First, the points of their needles are mostly rounded, unlike pointed needles of Douglas firs and Pacific yews. Second, almost every western hemlock has a tipping top. So, when you are out the field, trying to identify western hemlock, looking for the tipping top might make it a lot easier. This feature is shown in Figure 28, in which there is a small western hemlock.
Station 8: a visible effect of ecological disturbance
 |
| Figure 29, my station 8 |
 |
| Figure 30, my station 8, a snag |
Here is my station 8. Take a loot at the map shown in Figure 29, it won't be difficult to find this station. If you go pass the tennis court and look for a thick snag on your left, you will find it easily. This snag is clearly an visible ecological disturbance. At some point in the past, there was a super windy day. The wind was blowing blusterily that trees like this couldn't stand anymore. At last, this tree surrendered and was decapitated by the strong wind. After this happened, the tree was no longer called a tree. It was called a snag, which is one of the features of old-growth forest. Those features include Big trees, Uneven canopy, Understory, Nurselogs, and Snags. So, they are BUUNS altogether. Snags also a kind of legacies. Legacies don't have to be dead. They could be either alive or dead. There is a reason why they are called legacies. For example, after a snag is decapitated by a strong gust, someone else will benefit from this disturbance. In Figure 30, some kind of woodpecker has already built a nest in this snag. In fact, not only woodpeckers, but also many other species of birds can take advantage of snags. As my station 3 shows, black-capped chickadee can also take advantage of those legacies. From reading this forest, we really can conclude that nothing is all good or all bad. In this case, it is sad that the plant is decapitated by wind. However, its remaining part will be beneficial for others.
Station 9: animal behavior
 |
| Figure 31, my station 9 |
 |
| Figure 32, station 9 |
As Figure 31 shows, my station 9 is located pretty much at the center of Ravenna Park. If you walk along the main trail, no matter which way you come from, look for this patch of common horsetails (they might be giant horsetails). This station is also pretty closed to station 1. So, once you find the big erratic rock, you won't miss these horsetails. As messy as it looks, this station holds a song sparrow that has a lot of interesting behaviors. As for identifying a song sparrow, the most important feature is the black spot located at the center of its breast. It isn't always the case, but usually there will be a black spot forming when many streaks converging together. At the station, because Ravenna Creek runs through it, a lot of invertebrates like insects and earthworms live here. Since it provides this song sparrow with many food resources, it builds its nest here and marks this place as its territory. So, what about behavior? Since this patch of horsetail is so important to the song sparrow, it will certainly try its best to protect home. Every time there is an intruding song sparrow, the territory defender will display its territorial behavior. However, there are not as many intruders as you might think. So, you need to either mimic song sparrow's song by whistling or download some song files on the website. Thus, you could act as an intruding song sparrow to make it display is territory behavior. I posted a video of the song sparrow displaying its territorial behavior above. At that time, the song sparrow was singing loudly itself. Then I decided to "intrude" into its territory. Right after I played the downloaded song file, it came right into me and sang loudly again to try to drive me out of its territory. After it moved to the other side of the trail, I played my song file another five or six times. Then, it became really restless. The video was taken at that moment when it seemed like it didn't know what to do. It tried to attack me and sang loudly to exclude me. Nevertheless, I still remain at the same place as a intruding "song sparrow". So, it began to produce some "chi, chi, chi......" sounds and moved back and forth as shown in the video. It was also doing a wing-waving movement, in which it really looked disturbed. I didn't want it to feel angry anymore. So, I left quickly and I guess it went back to its nest and settled down again.
Station 10: evidence of restoration
 |
| Figure 34, my last station |
 |
Figure 35, sign
 |
Figure 36, restoration
 |
| Figure 37, a western hemlock |
|
|
Station 10 is a little bit tricky to find. However, if you follow the main trail and get to station 9, you would be pretty close to this station. At station 9, look for this sign as shown in Figure 35. Then, go on to the north tail. After hiking for a minute, you will be at station 10. This whole place is an opening area and it has a lot of restoration going on. It is mainly about growing native plants. For example, in Figure 36, there are many kinds of native plants being grown, snowberries, beaked hazelnuts, sword ferns, vine maples and so on. As shown in Figure 37, a western hemlock is also being grown here. Notice the small pink flag and also many other flags when you go there. They are showing that this place is under a restoration project. So, don't come too close so that you won't have any bad influence on their growth. As for the hemlock, this is a great example to show the feature "tipping top". This is also a place to show that human beings are able to realize their mistakes and correct them. Every time I came here, thinking about all those restoration projects people are doing, I felt pretty good about our future. No matter how many damages we've already caused to the natural environment, as long as we realize that we aren't supposed to do so, we still have a chance to improve and rebuild our environment.
Bibliography and resources:
Station 1:
Hendy, Ingrid. "A Fresh Perspective on the Cordilleran Ice Sheet." Geology. 37.1 (2009). Print.
No comments:
Post a Comment