Daily Sketch - Young Oak

For today’s weekend tree sketch I ventured out on bicycle to the local arboretum where to no surprise there are many trees. I sketched this young oak with De Atramentis Urban Gray ink and used Derwent Graphitint pan paints for the wash. I like the Derwent Graphitint pan set a lot. The principle of the Graphitints (both in pencil and pan paint form) is that they are watercolor pigments mixed with graphite particles which mutes the colors a lot. Using the pan set I find I can mix a lot of realistic greens, and muted sketches work well at times.

An AI Lesson From Urban Forest Mapping

Today I fielded an email from a staffer at the California Air Resources Board about the following topic, and I think there’s a general lesson to be had here. Between 2021 and 2023 I worked on a project that was looking at the extent of and ecosystem services provided by the urban forests of California. This was a follow-on to an earlier project our lab had done in 2015 about the same topic, and one of the goals of the project was to do a change analysis between the two time periods. For the question about urban forest canopy extent, we were working with high-resolution tree canopy cover datasets from a company called EarthDefine. In particular, we were comparing a canopy cover data layer from 2012 (used in our 2015 analysis) to a canopy cover data layer from 2018. In theory, all one has to do to measure in canopy cover extent is to subtract the 2018 layer from the 2012 layer. Pixels where there was canopy cover in 2012 but not in 2018, or vice-versa, would represent change.

In practice, we soon discovered this wasn’t going to work at all. These canopy cover datasets were developed using machine learning models applied over NAIP imagery, which is high-resolution aerial photography produced periodically in a program run by the US Department of Agriculture. When we compared the canopy cover maps in 2012 and 2018 with their source imagery, it was evident that the machine learning models for two canopy cover datasets used very different ideas about how to recognize and delineate trees in the source imagery. This resulted in unrealistic change statistics, for example the urban canopy cover in Riverside County purportedly increasing from 2012 to 2018 by 20%. Basically, the comparison was between outputs from different machine learning models applied over different datasets (in particular the 2012 imagery had a resolution of 1 meter, and the 2018 imagery had a resolution of 0.6 meters) — apples and oranges.

The general lesson for AI is to be very careful about extending an AI model beyond the domain over which it has been trained. Sometimes this works, but many times it does not, with deleterious consequences. In particular, this is one of the antipatterns that can result in AI bias.

Ripe Figs

While I was gone the figs on the tree out front got ripe. They have been the object of interest of the scrub-jays and squirrels, but this morning I saw the tail end of what I thought was a Nuttall’s woodpecker. It came back and turned out to have been a female black-headed grosbeak.

We had a fig tree out front when we lived at the Trout Club in Santa Barbara nearly 30 years ago; a grosbeak would visit it regularly when the figs were ripe. Numenius once made a fantastic sketch of one with fig detritus all over its beak; I wasn’t able to put my hands on this sketch today. I did try to capture the bird this morning (apologies for haste, I was also on the phone at the time) but afterwards also found evidence of its work, shown below.

Geology from the Air

The flight path from Sacramento to Seattle is full of volcanic wonders. First are the Sutter Buttes, proclaimed the smallest mountain range in the world. Next comes Mount Shasta, towering over Northern California and still, in late July, snow-covered. Into Oregon is Mount Hood, the astonishing Crater Lake, then approaching Seattle, Mounts Baker, and Tom in the distance, and Rainier to the east.

I know we live in a geologically active area of the world, but in Davis, you see little evidence of this. Today I had a good reminder that there’s a lot of geology all around.

Postscript: I do know it’s not a great idea to bring fountain pens on planes, but I do it anyway… Also, I wrote this before I heard about the 8.7 magnitude earthquake in Kamchatka, which reminds me also that yes, the Pacific Rim is a powderkeg.

Two Days at The Marine Mammal Center

I have just spent two days in the fog on the Marin Headlands, doing graphic recording for a workshop on vessel strikes on whales. Climate change and other causes are forcing whales to change their movement patterns and when they get hit by a ship — or even a pleasure craft, like a sailboat — they get injured and often killed. There is an estimate that of every dead whale that is recorded, either floating or washed up on shore, there are probably ten that are never seen. This is particularly bad in the case of gray whales which have been coming into San Francisco Bay more and more to feed, a body of water that is full of risks for them.

This was a group of scientists, tech folks and policy folks assessing the ways to find out more about where the whales are, what the boat traffic is doing (this is very well recorded for large vessels, less so for small fishing or pleasure craft), and what can be done to reduce or mitigate the risks. It’s a bit depressing especially in the current funding crisis but being around people who are so passionate about what they do, who keep trying to find ways to save the planet in the face of unbelievable odds, was inspiring.

Daily Sketch - Figs

Sketched with watercolor pencils and De Atramentis urban gray ink. None of the figs on this tree are ripe yet – maybe another two or three weeks?

Weekend Tree Sketching - Cypress

On weekends nowadays I head out to find a tree to draw as my daily sketch. Here is my sketch from this past Sunday of a cypress that is in front of a nearby church. When I sketched it I realized that the watercolors I wanted to paint it with were in my Schmincke pan color set back at home, so I finished it off there. The paints I used were raw umber for the trunk and perylene green and yellow ochre for the foliage.

Uncommon Landscapes

On my twice-daily walks I always carry a small camera in case I spot something worth photographing. But my walks don’t vary much, and lately I feel like I’ve run out of photographic subjects. Or have I?

Not long ago I watched a You Tube video about the photography of Stephen Shore. The video was by an artist named Tatiana Hopper who produces interesting content about the history of photography and filmmaking. It was good to be reminded about the work of Stephen Shore. He was one of the participants in the influential New Topographics exhibition in 1975 which presented photographs of ordinary human-dominated landscapes across the United States, with subjects like industrial parks, gas stations, and housing developments. Shore was the only participant who photographed in color, and he is one of the pioneers of artistic color photography. The photo of his at right was taken in 1974, and was published in his major photo book from 1982, Uncommon Places. It is quite typical of his work: a muted color palette, a strong formal composition, with a sense of detachment from the landscape.

I am clearly quite attracted to this aesthetic, and wonder if it provides a template for photographing the ordinary landscape of this college town. But does an artistic movement from the 1970s still have relevance in 2025, in an age when hundreds of billions of photos have been posted to Instagram? Interestingly enough, between 2014 and 2024 Stephen Shore posted every day on Instagram before deciding after 10 years it was time to move on from the practice. As a general principle, Stephen Shore’s Instagram Photos Are Better Than Yours. There is something about spending decades arranging photos on the ground glass viewfinder of an 8” × 10” view camera that inexorably leads to a heightened sense of composition. Photography is very much a matter of looking closely.

The Jasper Tax

Our neighbor who shares the duplex with us likes to put out peanuts early in the morning for our local scrub jay, whom she’s named Jasper. When she goes off on a trip I have the assignment of placing four peanuts out on the glass table in the front yard. Here is Jasper collecting his first peanut this morning.

Daily Sketch - Hollyhocks

Our neighbor has a veritable tunnel of hollyhocks by the sidewalk in front of her yard, and I think at one point seeds from those plants dispersed over into our backyard. Here is my sketch of the day of one of the pink hollyhocks in our yard.