Weather: Rain was forecast for Sunday, but all we got was the moisture streaming overhead that had come over central Baja. The clouds allowed me to begin cleaning grass and twigs from the driveway that usually is in the sun. Tuesday morning the moisture condensed into fog and frost. The soil got a little water that way.
Last rain: 2/23. Week’s low: 17 degrees F. Week’s high: 69 degrees F in the shade.
What’s emerging: cheat grass
What’s green: Junipers and other evergreens, cliff rose, fern bush, yuccas, grape hyacinths, garlic chives, garlic, vinca, coral bell, blue flax, hollyhocks, alfilerillo, coral beards tongues, pink evening primroses, Mexican hat, anthemis, yarrow
What’s gray: Bath pinks, snow-in-summer
Tasks: Monday I cut down a leggy winterfat in the retaining wall outside the gate. It was in a mound about a foot higher than surrounding land. Since some of its oldest branches were buried, that meant the shrub had been capturing dirt that was floating down from my neighbor’s land. I had installed the wall last year to stop that drift of dirt into the area in front of my gate, because it block it from opening in the winter.
To try to hold the land, I planted some Dutch clover seeds. Along the edge, near the drive, I put in some California poppy and African marigold seeds. I spread some ground red pepper on the soil, and then laid down a layer of cottonwood leaves to keep in the moisture.
Later that day, a delivery man used the flattened area as a place to leave a package for my neighbor. The winterfat had prevented him from doing that earlier. Since there’s no mortar in the block wall, it can’t take any weight.
The chickadees returned the next day. Before I could get to the area, they had disturbed the leaves and exposed some seeds. I replaced the leaves and laid down some pieces of wire mesh.
I figured that wouldn’t be enough to stop the tree cutting crew from using the space as a laydown area, so, before they arrived, I added some stakes along the edge, and tied a string between them.
Animal sightings: Robin early Monday, sparrow on the utility line later in the day, bird call on Tuesday around 6 am. That marked the return of the chickadees, who have been flitting about ever since.
The tree man said the locals called ground squirrels long-tailed rats. When he gave it in Spanish as ardilla de cola larga, he realized that translated as squirrel, but he implied people meant rats. He’s only used commercial products for them. On his own land he used the poison pills, and when he worked for the county, they used gas pellets. In both cases, he had to find a new tunnel to insert the pellet, and then stuff newspapers in the penetration hole. He said he killed hundreds on his land near the Chama river north of town.
Weekly update: As they say, by the time you know you have a problem, it’s too late. Last summer, the top third of my cottonwood lost its leaves. Last Thursday, a crew arrived to cut out the dead wood.
The crew chief said the problem was cottonwood borers that drilled into the wood, and killed everything above their holes. He said that did more damage to nursery-grown trees than native ones.
While he said cottonwood borers, he probably did not mean Cottonwood Borers. Plectrodera scalator is a large long-horned beetle that lays its eggs at the base of the tree, and the worms kill young trees by girdling them. It’s primarily a root living pest.
The Poplar Borer, on the other hand, attacks the trunks of trees that are at least three-years old. Unlike the Cottonwood Borer, Saperda calcarata attracts woodpeckers, who enlarge the holes.
I planted my cottonless, that is to say male, Souixland cultivar in 2004. It grew normally, but did not get too tall.
It had its first problem in June of 2012 when a branch broke off and blocked part of the driveway.
The next year, a branch died in the same general area, but remained in place. I thought the problem was lack of water, and began watering it more often. It got taller, and the staghead and hole from the broken branch were eclipsed.
Then, in 2016, one of those insect tents appeared in the same part of the tree. That is, it was on a branch pointing east over the entrance to my gate. I tried spraying it apart with water, but I couldn’t get close enough to destroy the nest. It simply collapsed on itself.
Last summer, the tree cutting crew removed the dead wood under the tree, and I cleared out the winterfat that had exploited the area. I was still concerned about it getting enough water. That summer and the one before had been much hotter. Delivering the same about of moisture didn’t mean the same amount was available.
I wondered how much duff to leave. I drove around the area and noticed leaves did not accumulate under local trees. Apparently, when they grow in the bosque, they get so much water from flooding, they haven’t adapted to dryland conditions. Instead of holding moisture in the ground, I reasoned the leaves acted as a barrier. When it rained, the ground did not get wet under the tree.
The reason leaves had accumulated under my tree was a vertical board fence on two sides trapped them. No leaves remained outside the fence where the wind could blow. I removed most of the leaves.
In April of 2019, the tree began leafing, and put out new growth on the trunk and on along one branch. It was making its own strategic retreat and recovering where it was safe to do so.
In summer, the branches that had grown above the insect nest began losing leaves.
A small black-and-white woodpecker appeared in mid-September, and kept returning until December.
Each time it was active, the block walk near the tree was covered with small ants. There was no nearby hill.
Now the tree has been cut back to the size it was before its great spurt of growth. Only time will show if the decapitation was enough to eliminate the pest, whatever it was.
Notes on photographs: Same tree, a Souixland cottonwood (Populus deltoides)
1. 2012 April 30, before any problems appeared
2. 2020 March 5, before the tree cutting crew arrived
3. 2012 June 29, broken limb
4. 2013 July 11, bare staghead limb
5. 2016 July 26, insect nest that collapsed from being sprayed by a hose
6. 2019 April 14, recovery attempts by tree
7. 2019 November 9, bare branches on dead wood
8. 2020 March 5, damaged wood; the neat, small holes probably were made by the borer; the ragged, larger holes probably were enlarged by the woodpecker.
9. 2020 March 5, tree with dead wood removed
End notes: R. C. Morris, T. H. Filer, J. D. Solomon, F. I. McCracken, N. A. Overgaard, and M. J. Weiss. Insects and Diseases of Cottonwood. United States Department of Agriculture, Forest Service Technical Report SO-8, 1975.
No comments:
Post a Comment