Doug's Mountain Journal
A Chronicle of Natural History on San Bruno Mountain
Doug Allshouse has been writing his seasonal Mountain Journal for many years. We are very pleased to share his reflections on the natural history of the Mountain. Together with David Nelson, he wrote San Bruno Mountain: A Guide to the Flora and Fauna. The book was published by Heyday Books in November 2022 and can be purchased here.
Autumn 2024
Autumn 2024 will be remembered as a dichotomy of a season. This September set a record for foggy days (24) and the amount of fog precipitation (0.39 inches), clearly beating out second place 2020-2021, which had 13 days and 0.30 inches. The eleven-year average for September is 8.6 days and 0.17 inches. Then October, which can be a Jekyll and Hyde kind of month, warmed up and made us wonder if Fall really was going to show up. November came in with a few rain showers and starting about mid-month Mother Nature got serious and the sky opened up to the tune of 12 days and 5.24 inches of rain, the wettest November on record beating 2018-2019 at 5 days and 3.70 inches of rain. So this Autumn has set two monthly precipitation records.
Serendipity
Something really fantastic happened in mid-October and early November. Last spring the County Parks Department received $30,000 from the State as a gift to mend the heartbreak of a couple of restoration projects on the Bog Trail. Mary Petrilli of GGNRA began working with volunteers in 2001 on a project on upper Colma Creek called ‘Heart of the Mountain’. A few years later Joe Cannon of Mountain Watch finished her project and started another on the lower bog trail with volunteers and supplemented by yours truly with Friends of SBM and student volunteers from Jefferson HS in the mid-2000s. Those restorations were eventually reversed by a lack of follow-up weeding sessions. With supplemental funds from Natural Resources Management, Go Native was hired to remove enormous amounts of cotoneaster, English holly, English and Cape ivy, gorse, small eucalyptus trees, and just about any other thing that was not native. Suddenly the ground was cleaner, the vistas were far-more open, and a general feeling of brightness conquered the dreariness of overgrown macro-weeds. I’ll have more on this subject in my winter journal.
Nuts for Buckeye
On a bright November Saturday, David Nelson and I met to check lower Buckeye Canyon for signs of water flows after our bomb cyclone dropped over 4 inches of rain from November 21st to the 23rd. The creek was flowing, as was the culvert from the quarry, but nothing to write home about. Then we saw the mature buckeye trees that escaped the wrath of the mudslide in 2022 and noticed that they were loaded with buckeyes. This was shortly after we spotted a coyote scat with small white pieces in it that puzzled us. What did this coyote eat? We crossed the creek bed, spied some buckeyes on the ground and cut one open. It was white as snow and our question was answered. In late spring of 2024 I noticed a plethora of newly-sprouted buckeye trees that so aptly have contributed to this eponymous canyon.
We decided to hike up to “the grotto” to check out the creek bed for suitable sites to plant chain ferns, which have disappeared from many spots around the Mountain. The grotto is a name David gave to the area by the creek adjacent to the shellmound. Prior to the mudslides it was a delightful shaded spot that was perfect for gatherings by a campfire, and a favorite spot of Brisbane residents for decades. On the way up the trail we noticed that the ground was littered with oak acorns—they were everywhere. Gathering a bunch we noticed that many had a tiny hole just above the cap, a trademark of an acorn weevil (Curculio glandium). This little brown beetle, about 3/8 of an inch (6 mm) long, has a very long, thin and curved snout (rostrum) and females use chewing mouthparts to bore holes into acorns while still on the tree. They then lay one or more eggs in the kernel. The eggs are laid in midsummer and the grubs feed inside the nut until autumn when the nuts drop to the ground. The legless nut weevil larvae are creamy white with a curved body that is fattest in the middle and have a brown head. They grow to about ¼ to 3/8 of an inch long and consume most of the inside of the acorn, which kills the nut. In late autumn or early winter the grubs bore perfectly circular holes about 1/8 of an inch wide to escape, and then they tunnel into the soil for one to two years before pupating and emerging as adults to repeat the cycle of life. If you want good acorns to plant, it’s best to get out early before the squirrels claim the good ones. They seem to know.
Curculio glandium, acorn weevil
photo credit: Janet Graham
An acorn with a hole drilled by a weevil
Acorns higher up the slopes of Buckeye Canyon. These, free of holes, didn’t seem impacted by acorn weevils
Late Autumn Magic
Spring is the season of massive blooms of wildflowers, summer has its moments, but autumn has a few unique surprises. We often, with good reason, consider the flower and petals to be the most beautiful part of a plant, but sometimes it is what comes after that may be the most striking. Slender willow-herb (Epilobium ciliatum subsp. watsonii) puts on quite a show late in the year. This moisture-loving herb has four deeply-notched pink-purple petals that are tiny. After pollination the fruit forms and is a straight to slightly-curved capsule with one row of seeds with white hairy tufts. Ciliatum is Latin for eyelash because of the slight fringing on the fruit, which allows for some seeds to be dispersed by the wind. When the fruit dries it curls dramatically and, along with the many other fruits, creates quite a sight to behold.
Another plant that saves its best blooms for autumn is umbrella sedge (Cyperus eragrostis), a tall stately sedge that gets its common name from the pointed, linear leaves that are almost as long as the stem. The Inflorescence is a compact head of flowers tucked within flat to rounded spikelets that are greenish-yellow. The spikelets are suspended at the top from umbel-like ribs that also resemble a parasol. Because this sedge is rhizomatous, you will find many together.
I encourage you to get to the Crocker Avenue gate(free entry) near South Hill Boulevard and walk the Old Guadalupe trail down to the junction of the OGT, Youth Camp, and Bog trails and walk the upper Bog Trail back to experience the openness and the vistas that were missing before this great work was done. I envision some volunteer work in the immediate future.
See you on the Mountain…
Doug
