Duff

Weather: Afternoon temperatures are still climbing into the 90s. The Forest Service found another small fire it could escalate into a major one with aerial ignitions. This one was in Valles caldera. For three days now I’ve been suffering from the effects of the polluted smoke.

Last useful rain: 8/11. Week’s low: 47 degrees F. Week’s high: 93 degrees F in the shade.

What’s blooming in the area: Hybrid roses, trumpet creeper, silver lace vine, red-tipped yuccas, Russian sage, buddleia, bird of paradise, roses of Sharon, purple garden phlox, datura, coreopsis, cultivated sunflowers

What’s blooming beyond the walls and fences: Buffalo gourd, bindweed, green leaf five eyes, silver leaf nightshade, alfalfa, white sweet clover, leather leaf globe mallow, goat’s head, yellow evening primrose, toothed spurge, prostrate knotweed, pigweed, Russian thistle, Hopi tea, native sunflowers, gumweed, wild lettuce, horseweed, goldenrod, golden hairy asters, quack grass, seven-weeks, side oats and black gramas.

Áñil del muerto has been blooming much of the summer in fallow market garden fields. It has only now begun to bloom along the roadside.

What’s blooming in my yard: Betty Prior and miniature roses, yellow potentilla, garlic chives, Royal Standard hosta, catmints, calamintha, winecup mallow, sidalcea, white spurge, large-flowered soapwort, David phlox, perennial four o’clock, Mexican hats, African marigolds, chrysanthemums, chocolate flower, plains coreopsis, black-eyed Susan, anthemis, purple coneflower, Mönch asters, bachelor buttons

Bedding Plants: Wax begonia, pansies, sweet alyssum, nicotiana, snapdragons

What’s Coming Up: Early summer seedlings have not grown; some are still at their second leaves. The ones that did come up have to be watered every day when the temperatures return to July highs. This is now September.

Tasks: With the moisture in early August, hay and other grasses revived. This past week people have been mowing.

Insects and fungus are taking advantage of the disappearing moisture and heat: powdery mildew has appeared on the Dr. Huey roses, and leaves on the peaches and cherries are getting disfigured. When I treated them with the available sprays nothing happened. I’m sure the base chemicals work, but I’m not sure the products do.

One thing I noticed this year was it was difficult to even find insecticides in the plant stores and local hardwares. This week I finally went to one of the big boxes to get something I hope works. I don’t know whether the chains or the manufacturers have instituted exclusive contracts, but I do know it seems as if they have.

Animal sightings: Rabbit, chickadees, hummingbird, geckos, bumble and small bees, heard crickets, grasshoppers, hornets, small ants

The Flame red grapes have been ripening for the past two weeks. I was able to eat a few each day. Saturday morning they were gone; not even a stem was left. I assume the rabbit leapt up, bit the cluster stems, then ate the fruit. It tries the fallen peaches, but only eats a little.

Weekly update: Earlier this summer, I cleaned leaves and dead shrubs from under the cottonwood. Recently, I’ve been doing the same under the Russian olive and some sandcherries. The tasks were similar, but the execution was not.

In each case, I first have to cut low dead branches to create a clearance. I was helped with the cottonwood by having someone cut some of the biggest limbs this past winter. All I had to do was cut smaller branches and winterfat.

The Russian olive was a different problem. The winter of 2013-2014 was particularly severe. Wikipedia said a polar vortex broke down in November, "which allowed very cold air to travel down into the United States, leading to an extended period of very cold temperatures. The pattern continued mostly uninterrupted throughout the winter." [1]

I wasn’t keeping detailed weather notes then, so don’t know exactly what happened. I did post an entry on 11 May 2014 on the consequences. Russian olives are not Siberian, but from a more temperate, moisture climate. [2] Trees everywhere in this area died back.

Once I cut or broke off the biggest branches, I had to defang the tree. It produces sharp, hard, wooden thorns. They aren’t poisonous, but pieces do produce infectiongs if they break off and get lodged under the skin. I didn’t always nip off the ones pointing up, but anything pointing down had to be removed.

It was after I had removed dead wood that I noticed the differences in the duff beneath the three species. Standard texts tell you that the duff is composed of three layers: the top strata of leaves and twigs, the bottom one of humus, and a middle one of organisms converting the one to the other. [3]

I know this basic model is valid. I remember seeing the various sorts of insects and worms that inhabit the middle world when I was in camp in Michigan. It was second growth hardwood, and I remember I would see them if I kicked over piles of oak leaves. But, of course, that was more sixty years ago, so I wouldn’t swear they were oaks.

That model does not appear here. As I mentioned in the post for 9 June 2019, the cottonwood leaves were fairly large and created a mat that stopped water from penetrating. It probably evaporated before it had time to seep down. [4] There was no humus, just bare dirt under the leaves.

Sandcherry leaves are smaller and seem to blow away. One is growing under a catalpa, and its leaves also move on. What falls to the ground are the dried shells of the seed pods. They create a web that allows water to go through. There were no signs of humus, but the soil had darkened from contact with decaying materials.

Russian olive leaves are small ovals that do drop. What I found under the tree was a caked layer of leaves and twigs, completely dried even though I watered the area every three days with a sprinkler hose. It had so much integrity, I could pick it up. It seemed like something that, given enough time and water, would turn into peat moss.

Under that layer, the ground was even darker than it was under sandcherry. Ironically, this hated invader seemed to be the only species capable of creating soil in this arid environment.

Notes on photographs:
1. Russian olive (Elaeagnus angustifolia), 24 August 2019. You can see the dead branches at the base of the tree on the right. I have a limited ability to cut thick limbs. Often the loppers act pliers that twist and break what I can’t cut.

2. Russian olive thorns, 15 March 2014. They are aborted twigs.

3. Russian olive as it was recovering on 19 April 2014. All the low growth was dead, and it was putting out new stems from the trunk. All of that still has to be removed. I haven’t worked that far under the tree yet. I’m still removing pigweed from the periphery.

4. Cottonless cottonwood (Populus deltoides) duff, 30 August 2019. Different colors marked the different generations of leaves, with the grayer ones the older. You can see in the bare spot that there has been no creation of new soil. There’s a volunteer juniper growing with it.

5. Sandcherry (Prunus besseyi) duff, 24 August 2019. The bare shot shows this duff is sitting on the bare ground, without interacting with it. However, you can also see that debris allows water to penetrate.

6. Dried Russian olive duff, 30 August 2019, seen from the side.

7. Duff under the Russian olive after the caked layer has been removed.

End notes:
1. Wikipedia. "2013–14 North American Winter."

2. Kris Zouhar. "Elaeagnus angustifolia." United States Department of Agriculture, Forest Service "Fire Effects Information System" website. 2005.

3. B. J. Stocks. Moisture in the Forest Floor - Its Distribution and Movement. Ottawa: Canadian Forestry Service, 1970. 1.

4. Stocks discussed the problem with evaporation from the duff.