North Yuba River from the Canyon Creek Trail - 11/11/22
The snow that fell last week is almost totally gone in our neighborhood. We've had dry, cold, windy weather this week. A lot of the trees are totally bare of leaves, but the California Black Oaks are still vibrantly colored in golden-yellows, oranges, reds, and browns.
The beautifully colored Fall leaves don't last forever. As the days shorten and temperatures drop, not only do the leaves change color, but a process called "abscission" begins. The leaves don't just fall off the tree, they are actually being pushed off the tree by the tree itself! Keeping lots of dead leaves on a tree could cause breakages from the weight of snow accumulating on them. As Fall progresses a layer of cells, known as the abscission layer, starts to grow between the end of the leaf stalk and the twig supporting it. These cells slowly grow and cut the leaf off from the tree without leaving an open wound.
California Black Oak - Quercus kelloggii
I was wondering why oak trees retain their leaves longer than other local deciduous trees, and this is what I found out. Oak leaves last longer because oaks form an abscission layer much later than other species of deciduous trees. Oak leaves often remain attached to the tree throughout the winter. This retaining of dead leaves is called "marcescence." Trees that exhibit marcescence are called "everciduous."
Marcescent California Black Oak leaves - Quercus kelloggii
Marcescence can also occur in trees when an early frost, or diseases and plant pests, kill the leaves before an abscission layer has formed. Marcescent leaves may be retained indefinitely and do not break off until mechanical forces, such as wind, cause them to snap off.
The are several theories why marcescence occurs including: protection of leaf buds from winter desiccation, or as a delayed source of nutrients or mulch when the leaves finally fall and decompose in spring.
Fallen Big-leaf Maple Leaves - Acer macrophyllum
When I was a kid, we used to rake up giant piles of leaves and run and jump into them. We also used to rake paths between them and race our tricycles on the paths. It was lots of fun! Our neighbors also used to rake leaves up and haul bag after bag of them to the dump. Now however, it's common knowledge that it's better to just leave the fall leaves on the ground and in your garden, because they are naturally beneficial to the health of the soil and the critters that dwell in them. The information from the following website
explains this process well.
"Leave the Leaves!"
"It’s the time of year to do your fall garden cleanup. Rather than the tedious task of raking and bagging leaves and taking them to the landfill, the best way to reduce greenhouse gases and benefit your garden is to leave the leaves!
Leaves create a natural mulch that helps to suppress weeds while fertilizing the soil as it breaks down. The leaves also serve as a habitat for wildlife including lizards, birds, turtles, frogs, and insects that overwinter in the fallen leaves. These living creatures help keep pests down and increase pollination in your garden, so having a habitat for them in the fallen leaves can help to keep them around when you need them the most.
Micro-organisms are the life of soil, and they need food and nutrients all the time. The more leaves left on your garden, the more feed for these micro-organisms that make soil healthier and plants grow stronger. As the leaves decay, they add organic matter back into the soil, which lessens the need for fertilizer.
You can also include leaves in a compost mix to use on your crops. Mulching is a simple and beneficial practice you can use to create a healthy garden, and if you have trees, you have free mulch at your fingertips each fall. Mulching can protect the soil surface and help stop erosion from rainfall. Mulch also helps to moderate temperature extremes by keeping roots warmer during the winter and cooler in the summer, and helps to keep moisture in the ground, which is especially helpful during times of drought."
The Open Slope
Neighborhood Sightings!
Now that the Lakes Basin has a good foot or more of snow, I haven't been hiking up there. Instead I've been wandering in my own neighborhood. It's been lovely! I re-visited the open slope a few days after the snowstorm and it was warm and sunny once the mists cleared off. Several migratory songbirds were also visiting the open slope! To my delight there were Western Bluebirds, Lesser Goldfinches, a Meadowlark, a Townsend's Solitaire, and even a Yellow-rumped Warbler!!! The Goldfinches were feeding on Star Thistle seeds, the others were feeding on insects. Most of these birds are short-distance migrants, and will spend the winter locally or down in the snow-free elevations of the foothills and central valley.
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Western Bluebird (male) - Sialia mexicana
Lesser Goldfinch (male) - Carduelis psaltria
Western Meadowlark (adult) - Sturnella neglecta
Townsend's Solitaire (adult) - Myadestes townsedi
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Yellow-rumped Warbler (male) - Setophaga coronata
Bald Eagle (adult) - Haliaeetus leucocephalus
A few local Raptors!
Just this week I saw a Bald Eagle perched above the river in our neighborhood! I hadn't seen one in months and months! It stayed perched for more than ten minutes on a tree that many large birds perch in! The tree is in a good location, right above some deep pools on a bend in the river. I was so pleased to see one return to our area, they are quite uncommon here! So impressive!
To read more about the natural history of Bald Eagles, just enter "Bald Eagle" in the "search this blog" bar on the top right. I've written about them extensively in previous blogs.
Northern Pygmy-Owl (adult) - Glaucidium gnoma
One late afternoon this week, around 4:30, my husband and I were walking along the road when I spotted the silhouette of a tiny, broadly round-headed bird on a bare branch. I instantly recognized it as a Pygmy Owl! Oh WOW!!! It was in the same area we spotted one last year, and at the same time of day!
Northern Pygmy-Owl (adult) - Glaucidium gnoma
I rarely see these lovely little diurnal owls, that are only 6.75" tall! Last year, the owl took off while we were watching it, so I hot-footed it up to the cemetery on the off-chance it would show up there. The cemetery is bordered to the west with trees and faces a big open dry meadow to east. A perfect place for a Pygmy Owl to perch and scan for prey, such as songbirds! Luckily the little owl showed up and posed for me in a big bare-branched cedar tree! Such beauty!
You can read all about that sighting and the habits of Pygmy Owls by going to my "Local Raptors" blog on Jan, 2, 2021.
Northern Pygmy-Owl (adult) - Glaucidium gnoma
These are the photos I took last year in the same bare branches, and maybe it's even the same Pygmy Owl! So Cool!
Red-tailed Hawk (adult) - Buteo jamaicensis
I continue to see a Red-tailed Hawk in our neighborhood, usually along the river. This week it flew across the river with a critter in its claws, and landed in a distant tree!!! The road that runs parallel to the river is probably a great place for it to catch squirrels!
Unknown mushrooms
Mushrooms!
Mushrooms are starting to pop-up in the forest! If we get some more rain even more will "blossom". Here are a few that my friend Rod spotted in a grassy field right off the highway. I've only seen one Shaggy Mane in my life, so this was my second one! How fun!
Unknown mushrooms - Shaggy Mane
species unknown - Coprinus comatus
Raindrops on Locust Leaves
Damp Earth Art
I'm going to keep posting rain inspired writings, art, etc. on my blog at dampearthart.blogspot.com. Any submissions would be greatly appreciated. Please join me in my continuing hope for precipitation! Perhaps our collective efforts may help it happen.
What's happening on the river?
What's happening in the foothills?
Check back next week for the answers to these questions and more!
Unfortunately, you can no longer sign up to get my blog via email. Just go to northyubanaturalist.blogspot.com directly.
Your questions and comments are greatly appreciated. Please feel free to email me at northyubanaturalist@gmail.com. Thanks!
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