The male flowers aren’t as subtle as the female flowers but they do blend into the spring green that is sprouting throughout the landscape. The male flowers are a yellowish green and hang on a thin catkin. The catkin emerges from the tree fairly compact. As it elongates the clusters of stamens spread out, open to release their pollen, and look wispy and light as they blow in the wind.
The male and female flowers are on separate inflorescences on the same tree. Oak trees are wind-pollinated.
Walking into Mt. Pisgah Arboretum you are greeted by the iconic Oregon White Oak and it is the logo of the arboretum. This beautiful, mighty tree is vital to creating a diverse ecosystem and produces nutritious acorns which are a food source for many animals. When the acorns are ripe, jays can be seen carrying them off in every direction to cache them for the winter.
We all know acorns, and I will often hear children refer to oak trees as acorn trees. That said, I imagine that most people are not as familiar with the female flower that gives rise to this nutritious nut. I am here to introduce you to this tiny flower that can easily be overlooked. They grow from the axils (where the leaf stalk meets the stem) of the new leaves. The Washington State Native Plant Society describes the flowers as: “The pistillate flowers grow singly or clustered. Each pistillate flower is surrounded by a scaly, cup-like involucre, contains an inferior ovary and 3 styles.”
Okay. I see the small acorn flower. What I can’t find described or mentioned is the red-tipped appendage that is growing up from the base next to the flower. It seems like it is part of the flower in some way, but I haven’t found any reference to it in any of my research, so far. There is only one, even if it is a pair or a cluster of three flowers. What is that structure and how does it fit in?
The last three photos below show small acorns forming. I took the photos of them last year on May 30.
I hope you are enjoying spring and are finding time to get out and explore.
Reference
Quercus Garryana Var. Garryana. https://www.wnps.org/native-plant-directory/232-quercus-garryana-var-garryana. Accessed 15 Apr. 2024.
Bigleaf maples have small, yellow-green flowers with short stalks. The flowers grow in a cluster that hangs downward like a pendant as it develops. Interestingly, bigleaf maples have two mating types. As the flower clusters emerge and start blooming, the initial flowers that open on the first type of tree are female; on the second type, it is the males. As the cluster grows, the male flowers will begin to emerge on the female flower clusters, and the females will start to develop and open on the male flower clusters. Each tree contains both male and female flowers, making it monoecious.
These flowers are a great nectar and pollen source for insects. As I took these photos, the blossoms were buzzing with activity. Male and female flowers both produce nectar, so pollination occurs as the insects move between the two types.
Beekeepers who have honeybees love it when warm, sunny weather coincides with the blooming of bigleaf maple trees. A strong colony of bees can produce enough honey to harvest some in the spring. To my tastebuds, honey made from the nectar of bigleaf maple trees has a distinctive peach flavor. It’s yummy!
Nature is an inexhaustible source of wonder. I look forward to seeing you out there.
Resource
Wagner, David H., A Lane County Almanac. Northwest Botanical Institute, 2021.
I have been looking at the cottonwood trees that fell over during the ice storm as I have written about recently. I had one more thing to share. The small branches at the tops of the trees had an interesting structure. They were knobby from what appears to be old scars created from where the previous years’ leaf stems were attached. With the new leaves sprouting out of the top, it reminded me of a palm tree. The stems also looked like they had been stacked likes rock cairns—beautiful formations.
Where the stems attached to the larger branch, there were thick, bowl-shaped nodes. Many of the larger branches were bumpy with scars where these smaller stems had broken off.
I love this tree!
It is spring, and the cottonwood leaves are awakening from the quiet repose of winter. The warmth of the sun kindles their dreams, bursting their flaming sheaths. The combustion releases a syrupy aroma that flows and eddies in air currents along the river. Its swirling fragrance is a calming dizziness. The leaves erupt into an untamed bouquet and ripple outwards like the water they so love. Their bodies will uncurl into ovate blades to scoop up the sun. They will dance and collide in the wind, circulating a song of water in the blue sky of summer. I am looking forward to luminous July days and sitting in the shade of the cottonwood tree. I will uncurl my toes in the water and watch the waxwings swing between the trees over the river.
The iris plunges forth.
A watercolor brush
dipped in violet.
The pigment seeping
into its pulse,
ready to dab its radiance
onto the complexion of spring.
I was back poking around the river again. I saw this small log lying on the ground and decided to turn it over to see if anything cool was hiding underneath. To my surprise, I saw a branch from one of the fallen cottonwood trees that had started to sprout roots. The log had been deposited there from the river swollen from recent rains. The moist, dark conditions under the log were perfect for sprouting new roots. I imagine that most water-loving trees and shrubs that grow along streams, ponds, marshes, etc., have evolved to sprout new roots from limbs easily.
The black cottonwoods sustained considerable damage during the recent ice storm and thousands of limbs that broke off during the storm are lying on the ground along the river. It is heartbreaking to see all the damage, but there is one fortunate side to this story. Some of the trees that fell over still have some roots in the ground which supply enough nutrients to keep them growing. As spring arrived, these trees sent out the male and female flower catkins. This is a great opportunity to see the flowers up close which are normally out of reach on the tree where you can’t easily view them. Black cottonwoods are dioecious, meaning the male and female flowers are on separate trees.
The female flower is interesting. The most obvious feature is the curvy, fleshy, yellow parts projecting out of the top which I interpreted as the stigma that receives the pollen. I took a photo of it drying out and turning brown which gave me a better understanding of its shape. Underneath this is a green, fuzzy capsule that is firm to the touch. I cut one in half to look inside. The walls were thick and a bundle of seeds were nestled inside. This capsule will become brown, split open, and release small seeds with white, fluffy parachutes. When the seeds are being let go it looks like snow blowing around through the air.
The males have 40 - 60 stamens that start as small, red pods. The catkin will continue to grow and elongate. Upon maturity, the red pods split open and release small dust clouds of yellow pollen.
Nature is an inexhaustible source of wonder. I look forward to seeing you out there.
There are limbs and piles of debris lying around throughout the arboretum since the ice storm. Many birds are hopping through them and using them for cover and searching for food. I enjoyed watching this Downy Woodpecker investigate some of the fallen dead branches.
In the first photo, it appears that both feet briefly left the limb as he struck it. Like in the previous post, a bird’s movements happen in the blink of an eye, so I feel some actions are only observable by capturing them with a photo. It is interesting to see him seemingly throw his whole body into it as he forcefully struck the limb.
As he chipped away the bark, I occasionally saw him trying to pull off pieces of bark to get underneath. He was so determined as he tugged on them.
As he went along, he circled the whole branch. While clinging underneath, he easily moved along as he poked and searched for food.
This bird has a great spirit and is fun to watch. Happy birding!
The other day I was snapping a few photos of a Bewick’s Wren singing. When I got home and looked at the photos, I saw this one. It is out of focus, but it captured the wren launching from the branch and doing an interesting maneuver. It was twisting its body to where its feet are towards the sky as it looks downward as it flies to a lower perch. I can’t figure out why it would flip over like this as it took off. Maybe it flipped over and did a full twist. I don’t know. Little birds like wrens and kinglets dart so quickly through the branches that they might do tricky, acrobatic moves like this all the time. These movements happen so fast that you aren’t able to notice them. Maybe he was showing off for a female that was watching nearby.
According to my dad, Founder of the Odell Society of Weiner Stand Hijinks and Oddball Medicolegal Terminology of Unexplainable Ailments, he might have the “Hygolican Flips!”
If I look around enough, I feel as if I could find a dandelion blooming any time of the year. As the first day of spring approaches, they are starting to bloom and soon they will blanket vacant lots, the sides of roads, untidy alleyways, parts of unmown lawns, my garden, and along some of the trails out at the arboretum.
The flowers are bright, yellow bursts that attract many insects looking for pollen and nectar. They are edible and on occasion, I have made little fritters from them. I have also made dandelion wine from the flowers too. The leaves are edible and nutritious. The root can also be roasted and ground to make a hearty beverage.
The reason I set out to make this post was to show you that the flower stalks are hollow and if you pick the flower, the stalk will ooze this milky, white substance. This is one of the characteristics that help you identify them.
Also, keep an eye on this plant as it forms its seed heads. They attract lots of birds like juncos, sparrows, and goldfinches. Last spring I was on the campus of Oregon State on a cool, blustery day and watched goldfinches all around campus foraging on dandelion seeds. There were small patches throughout the landscape that had escaped the groundskeepers. One of their superpowers is being able to duck under a lawnmower! Dandelions rock!
When out birding it can be tough to distinguish between a coopers hawk and a sharp-shinned hawk. They are hawks that can whiz by you before you get a good look. I believe this one to be a Cooper’s Hawk that has caught a Northern Flicker. I put the measurements of the three birds below so you could compare them. The following data was taken from All About Birds by The Cornell Lab.
Measurements: Coopers Hawk
Male Length: 14.6-15.3 in (37-39 cm)
Female Length: 16.5-17.7 in (42-45 cm)
Measurements: Sharp-shinned Hawk
Both Sexes: Length: 9.4-13.4 in (24-34 cm)
Measurements: Northern Flicker
Both Sexes: Length: 11.0-12.2 in (28-31 cm)
In the photo, it appears to me that the hawk is considerably larger than the flicker. The Cooper’s Hawk has a more squared head than the Sharp-shinned Hawk which has a smaller, rounder head. Both birds can be seen out at the arboretum. Most of the time I hear the alarm calls of songbirds to clue me into the presence of a Cooper’s or Sharp-shinned hawk. It is amazing to watch the speed and agility of these birds as they navigate through the landscape in pursuit of prey.
I am putting a link to an informative page by The Cornell Lab that compares the two hawks side by side. Click here.
Good luck and happy birding.
Birds need to care for their feathers. They are important for such functions as flight, attracting mates, camouflage, regulating body temperature, and keeping dry.
On warm, sunny days out at the arboretum I will occasionally catch a Steller’s Jay or an American Robin performing an interesting behavior called sunning. This maintenance behavior isn’t completely understood but seems to be largely associated with removing parasites, such as lice, living on their skin and feathers. Studies have shown that exposing the feathers to direct sunlight can allow them to heat up enough to kill some of the lice. In addition, lice might move to escape the heat possibly making it easier to clear them away during preening, which often follows a session of basking in the sun.
While scientists continue to unravel this mystery of sunning, one thing for sure is that we will all continue to marvel at the beautiful diversity of the colors and patterns of bird feathers.
Nature is an inexhaustible source of wonder. I look forward to seeing you out there.
Resources
Hot, Bothered, and Parasite-Free: Why Birds Sun Themselves | Audubon. 27 Feb. 2020, https://www.audubon.org/news/hot-bothered-and-parasite-free-why-birds-sun-themselves.
Sibley, David. What It’s Like to Be a Bird: From Flying to Nesting, Eating to Singing -- What Birds Are Doing, and Why. Alfred A. Knopf, 2020.
I love the young bark of bigleaf maples. The green and white stripes on the surface are broken and cracked creating a beautiful pattern that reminds me of the skin of a watermelon.
The young stems of trees can be green and it is usually in the beginning of growth. From my observation, this can last for years before the bark thickens and starts to turn gray or brown in most trees. The stem pictured here is a sprout growing from the base of a big leaf maple, and I estimated it to be around seven years old or more. According to the Oregon Wood Innovation Center of Oregon State University, a bigleaf maple can reach 300 years of age, so I count this as still beginning growth.
Chlorophyll is the green pigment, present in all green plants that is responsible for the absorption of light to provide energy for photosynthesis. So I imagine that the stem of this tree can photosynthesize. I wonder if photosynthesis in young stems occurs just as much in the winter when the stems aren’t mostly covered in the shade of the canopy of leaves as in the summer.
Stomata are small pores on leaves that play a central role in photosynthesis by allowing carbon dioxide to enter the leaf and oxygen to exit the leaf. So my next thought was how does the exchange of gases occur in the stem if it is photosynthesizing?
The Royal Horticultural Society had this to say on their website: “Leaves and soft, green stems have living cells in contact with the air, and they can absorb oxygen for respiration directly through their surface. However, the bark of woody stems is impervious to gases, so to get oxygen to the active tissue beneath, it is perforated by pores called lenticels.”
In the photo above, I think the woody little bumps are lenticels. When reading about lenticels, the articles were about them absorbing oxygen and releasing carbon dioxide and water vapor during respiration. I haven’t found any articles involving lenticels and photosynthesis yet. As a side note, I thought that it was interesting that apples, potatoes, and avocados have lenticels too.
I am still researching photosynthesis in the green bark of trees, but I thought I would share some of what I have learned so far to get you interested in reading about it too.
Resources
Bigleaf Maple (Acer Macrophyllum) | Oregon Wood Innovation Center. https://owic.oregonstate.edu/bigleaf-maple-acer-macrophyllum#:~:text=Size%2C%20Longevity%2C%20and%20Form&text=Bigleaf%20maple%20is%20moderately%20long,after%2050%20to%2070%20years. Accessed 20 Feb. 2024.
How Plants Breathe / RHS Gardening. https://www.rhs.org.uk/advice/understanding-plants/how-plants-breathe. Accessed 20 Feb. 2024.
Check this out. Out in the south meadow, some bigleaf maples are growing out in the full sun and the young bark on the stems is red. Can these photosynthesize too? Why are they red?
The white-breasted nuthatch is one of my favorite birds, and its curious, carefree spirit is an essential part of the oak savanna habitat of the arboretum. I always look forward to hearing its vocalizations and watching it hop and skip around on a tree.
It has an interesting behavior of moving headfirst down a tree as it forages. It will often pause and tilt its head back to have a glance at its surroundings. In David Sibley’s book What It Is Like to Be a Bird he says this about how nuthatches move around a tree:
”They do not use their tail for a brace when climbing—just their two feet clinging with sharp claws. The hind toe is particularly important for clinging, and it’s relatively large and strong. Usually they position one foot above the other so that the lower foot acts as a brace while the upper foot clings to the bark. This allows them to move easily up or down the trunk and at all angles on branches.”
It primarily eats insects, insect larvae, and spiders. They have pointy bills for probing into bark furrows and beds of moss and lichen growing on the tree. It also eats nuts and seeds. They love to retrieve bits of acorns from the parking lot that have been run over by cars. It will wedge a piece of acorn in the bark of a tree to hold it while it breaks off pieces to eat or will stash it for later. I also see it collect seeds like Douglas-fir.
Peterson describes its voice as: “Song a rapid series of low, nasal whistled notes on one pitch: whi, whi, whi, whi, whi, whi or who, who, who, etc. Notes of birds in interior West higher pitched and given in rapid series. Call a distinctive nasal yank, yank, yank; also a nasal tootoo.”
This is a fun bird to watch and get to know. I posted about this bird a couple of years ago and wanted to repost it. I hope to see you out there.
Resources
Peterson, Roger Tory, et al. Peterson Field Guide to Birds of Western North America. 4th ed, Houghton Mifflin Harcourt, 2010.
Sibley, David. What It’s Like to Be a Bird: From Flying to Nesting, Eating to Singing -- What Birds Are Doing, and Why. Alfred A. Knopf, 2020.
White-Breasted Nuthatch Overview, All About Birds, Cornell Lab of Ornithology. https://www.allaboutbirds.org/guide/White-breasted_Nuthatch/overview. Accessed 15 Feb. 2024.
Check out these oak leaves that I put in a slideshow. I collected them off the ground under a cluster of oak trees. I was so surprised and fascinated by the amount of variation in shape. I wondered how the field guides on my shelf described the leaf’s shape. Here’s how four different books define it:
Cascade-Olympic Natural History:
“…deeply pinnately blunt-lobed.”
Plants of the Pacific Northwest Coast:
“…deeply round-lobed oak leaves.”
Trees to Know in Oregon:
“Pinnately lobed with 7-9 rounded lobes; lobes often irregular.”
Trees and Shrubs of the Pacific Northwest: “…oval to egg-shaped… edges deeply lobed, lobes and leaf tip rounded.”
I searched for the term pinnately lobed and the University of Texas at Austin defined it as: “PINNATELY LOBED: lobes are arranged on either side of a central axis, like a feather.”
Having never seen an Oregon White Oak leaf, would you have visualized these leaf shapes in the photos based on the definitions from these books? Also, having seen an Oregon White Oak tree, what leaf shape would you have drawn from memory?
References
Botany Basics: Understanding Leaves. https://biodiversity.utexas.edu/news/entry/leaves. Accessed 10 Feb. 2024.
Jensen, Edward C., et al. Trees to Know in Oregon. Rev. April 2005., Oregon State University, 2005.
Mathews, Daniel. Cascade-Olympic Natural History. Raven Editions in conjunction with the Audubon Society of Portland, 1988.
Pojar, Jim, and Andrew MacKinnon. Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia & Alaska. Revised ed, Lone Pine, 2004.
Turner, Mark, and Ellen E. Kuhlmann. Trees & Shrubs of the Pacific Northwest. First edition, Timber Press, 2014.
Scattered across the ground, are heaps of branch tips of big leaf maples that broke off during the ice storm. I picked one up and admired its shape, color, and texture. I sat down, did a brief sketch of it, and continued to admire its beauty. Afterward, I cut a cross-section to see what it looked like inside. To my surprise, I found a small tree enshrined in a kind of mandorla. (In Italian it means almond. In religious art, it’s the almond-shaped aureole of light surrounding the entire figure of a holy person like the Virgin Mary.)
Nature is an inexhaustible source of wonder. I look forward to seeing you out there.
Soft, white lights illuminate the wetlands. They twinkle like stars, guiding us through the grays of winter. I imagine moths dancing around their gentle flames in the night. They are brushes waiting to dip their bristles into the paint pot of spring.
Flares of green are igniting across the hillside. Cascading, white lamps emit rays of light and levity. The renewal of spring is beginning to shine.
I wanted to post some photos of willow catkins emerging because I found their forms, colors and textures so elegant.
The female catkins are in a small cluster above the male catkins. The females are about a quarter of an inch long. That’s fairly tiny and easily overlooked, especially if they are dangling from branches above your head. In the photo, you can see the red styles protruding out from underneath the green scales. This will form a small woody “cone” about an inch long with winged nutlets inside. “Cone” is in parenthesis because it seems that this word is reserved for the fruit of conifers. The “cones” of the alder are referred to as strobiles.
Alders are wind-pollinated and the female flowers do not produce nectar. The insects are drawn to the pollen of the male catkins.
The woody strobiles in the photos are still hanging on the tree from last season.
