Goethe's methodology is mutual and intimate interaction of observer and observed; and, what transpires over time. Ideally as the experimenter's observed knowledge grows from their study of natural phenomena, so does their capacity for inner awareness, insight, imagination, intuition and inspiration.

Goethean science - Wikipedia

The Healthy Riparian Zone

In upper Eaton Canyon, just before the bridge, there is a very special area. Most people that visit the area follow the conga-line up-stream to the waterfall. But a few, being called by the sound of flowing water, turn left at the bridge to stop and visit a small riparian pocket. Alnus rhombifolia (White Alder) line the streambed, sharing the banks with a few Planatus racemosa (Western Sycamore). Water flows freely year round this high up in the canyon, keeping the tree’s feet wet. The tight canyon walls are upstream, so these trees have sunlight all day long. Despite the full sun overhead, the streambed is well shaded by the Alnus canopy of leaves. This small area has seen few disturbances over the years, allowing the Alnus’ to grow tall, full of branches and leaves. Under this shaded area, very few, if any, plants live under the Alnus’.

The missing branches from healthy Alnus tree's creates a gallery of modern art on their trunks.

The red roots of the Alnus rhombifolia host nitrogen-fixing bacteria.

A thick canopy of Alnus leaves shade the streambed below, and provide housing and food for the community of species living in the canopy.

In decay, the Alnus leaves display their inner beauty.

Alnus branches almost reach the ground on both sides of the riparian area, blending into the nearby Eriogonum faciculatum (California Buckwheat) growing in an adjacent community.

The exposed roots of a Platanus racemosa (Western Sycamore) extend outwards in a radial pattern.

With water running year-round at this location in the canyon, the streambed is a mecca for animal life.

Fur-filled scat from Canis latrans (coyote) is left on the paths leading up to the riparian area. If this mammal is in the area, Ursus americanus (Black Bear), Odocoileus hemionus (Mule Dear), and Lynx rufus (Bobcat) are usually not very far away.

The Sceloporus occidentalis (Western Fence Lizard) also makes a home in the Riparian Community of Eaton Canyon.

Even in late October, the stream still hosts tadpoles. Legs sprouting, the tadpoles hurry to join the mature Pseudacris cadaverina (California Tree Frogs) camouflaged on the near-by rocks.

The slow-moving water provides refreshment for everyone.

Spiders build their webs near the water, hoping to entangle a tasty meal.

A gerrid (Water Strider) uses surface tension to glide over the water, casting its tell-tale shadow on the gravel below.

Man's presence

It amazes me that despite the number of visitors the Canyon hosts every day there is not more trash. Yes, there is some trash, including empty plastic bottles, bottle tops, corners torn from granola bars, used condoms, the occasional empty spray paint can, odd pieces of fruit including small pumpkins and halves of coconuts. Here, a tadpole has re-purposed a coconut half as a habitat.

Then there is the Stultus hominibus (human idiot) who carves up trees with pronouncements of love and attempts at immortality.

Despite the proximity to civilization and the sheer number of people who come to the canyon, the area is not covered in litter. Most visitors are respectful and leave few traces. Most come to simply enjoy connecting with nature.

The Dead Zone

In the riparian area below the bridge, there is an abrupt change in the Alnus Rhombifolia from a healthy living section to a dead Alnus zone. There is one living Planatus racemosa (Western Sycamore) at the edge of the dead zone.

In the dead zone there are no Alnus leaves to filter the sunlight. There is more illumination, and the banks are green with plants. Many plants are invasive non-natives, such as Ageratina (snakeroot). Other plants in the mix include Veronica (Speedwell), Erythranthe cardinalis (Scarlet Monkey flower), Solanaceae (Nightshade), Baccharis Salicifolia (Mulefat), some Salix (willow), Verbascum (mullein), and Nicotiana glauca (Indian Tree Tobacco).

There is no evidence of Alnus saplings in this area.

I cannot tell how long the trees have been dead. Most are still standing. A few crisscross the streambed.

Others lean away from their dead mates, gravity pulling them down to earth. Farther downstream, the dead trees have given up their battle with gravity and lay prostrate on the banks.

The streambed in the dead zone is mostly covered with a sticky silt. By comparison, the streambed under the healthy trees is mostly gravel. When walking through the water in this section, a shoe is easily trapped in the sticky silt.

Peeling bark exposes dead wood and the evidence of insects. The insects are most likely taking advantage of the dead wood, and were not necessarily the cause of the tree's demise.

I recently had an opportunity to talk with Rebecca Latta, a certified Arborist. She has surveyed this area during the past few years, working as a consultant for the City of Pasadena.

According to Rebecca, there could be multiple suspects responsible for the dead zone. In recent years, the Shot Hole Borer has been present in the area. Years of drought and heat, like the 118-degree days in the summer of 2018, and floods during 2005 and 2018, could all take their toll.

Silt, likely deposited by flooding, suffocates the roots of the Alnus. No oxygen can get through and the roots rot. The wet years also open the door to bacteria, creating open lesions in the bark.

The cause of the dead zone is most likely a combination of more than one disturbance. I can find no flaw with Rebecca’s analysis.

In a private garden, a property owner might remove a dead tree. In a natural area it is important to leave the dead trees in place, as bats and owls can take advantage of the open space in the trees to hunt their prey. And as the trees fall and decompose, their nutrients will feed this community and others downstream.

This have left me wondering why. Why are there two so very different areas so close in proximity to each other? Why is one thriving, and the other going through succession? What was the key disturbance that so dramatically affected one area, but not the other.

Going forward, I will continue to use the Goethean method to observe this area.