Amateur Naturalist: Forest Ecology & Creation Of Dendroglyphs
Picture 1: The areas inside the red outlines were burnt by a forest fire. The points show where dendroglyphs have been found in the unburnt forested areas. Courtesy photo
Picture 2: The darker shaded, south facing slope to the Jaramillo creek is shown in the lower side of the picture. The locations of the great majority of dendroglyphs are shown on the lighter shaded, north facing slopes. Courtesy photo
Los Alamos
The ecology of forests is the result of interacting factors. The aspen groves in the Jemez Mountains provide an example of these interactions. One factor involves forest fires. Sections of forest have been burnt over the decades. A second factor involves elevation. Aspen trees grow at high elevations and so are found toward mountain tops. A third factor involves the direction of a mountain slope. A south facing slope receives more sunlight but moisture from snow of rain fall evaporates away more quickly than a north facing slope. Plant life may be less plentiful in spite of the sunlight.
The growth of aspen trees incorporates these three factors. An overall forest may be good for the growth of aspen tree but a section may not have aspen trees due to a forest fire. Groves of aspens may be found growing from 8,800 to 9,200 feet up a mountain side but not as common lower or higher. The elevation of a mountain therefore can be indicated without having to actually measure it. Aspen trees are more common on north facing slopes due to more moisture being available. A north facing slope also may have a gentler slope. It can retain soil that is good for aspen growth.
Aspen trees have a particular connection with history. The bark of younger trees is smooth and white. Sheepherders in the past century carved the names of people, towns, or dates on the bark. These carvings are called dendroglyphs.
The lives of sheepherders can be associated with the three preceding factors. Carvings found at high elevations show that sheepherders were willing to take their sheep to these areas for grazing. Lower elevations may have been more accessible and had better growing conditions but it still was worth while to go to higher elevations during the summer. They also may have been attracted to the scenic views at the top of mountains in addition to farming considerations.
Dendroglyphs are found more extensively on north facing, gentler slopes. These slopes often are closer to the grasslands where sheep grazed. Dendroglyphs that are common in certain areas of north facing slopes indicate where sheep were more commonly kept. They also indicate particularly good growing conditions for trees.
Sections have been burnt in forest fires. Dendroglyphs in these sections have been lost. Burnt sections are adjacent to unburnt areas that have many dendroglyphs. The adjacent burnt sections therefore may have had dendroglyphs as extensively as in the unburnt areas.
As one example, 71 dendroglyphs have be found a triangular area adjacent to St. Louis creek. Sixty one (61) of these dendroglyphs are on a northward facing slope that has grasslands on its northern and western sides, (see picture 1 above).
Approximately a third of this area has been burnt by forest fires. If the fires had not occurred then proportionally there may have been 107 dendroglyphs in this area.
As a second example, 190 dendroglyphs have been found in an area adjacent to Jaramillo Creek, (see picture 2 above).
One hundred sixty seven (167) of these dendroglyphs also are on north facing slopes, or 88 percent of the total count. Approximately a third of this area also has been burnt by forest fires. There may have been 63 dendroglyphs in this now burnt area, or possibly 285 for the total area.
These two counts show the impact of north facing slopes on tree growth. The actual or estimated dendroglyph counts also show that sheepherding was an extensive business activity.
Aspen trees have a life span of approximately 150 years. This means that the trees were young when sheepherders carved them 100 to 125 years ago. The trunk of an aspen tree would have become larger in diameter as the tree grew. This type of growth meant that vertical cracks could develop in the bark. Dendroglyph letters would be pulled apart. Bark also could grow next to carving cuts and distort the shape of letters. Words today often are divided into separate letters and not legible. Dendroglyphs often only indicate that sheepherding occurred in an area without having clear words.
There are occasional exceptions. A person named Alejo Luhan is an example. He used a cursive style for writing rather than block letters. He also carved the name of towns and included dates (see pictures 3A and 3B). A question remains. Why was his writing not distorted by the growth of an aspen tree?
Picture 3A: Alejo Lujan carved his name, date and the town of Cow Springs in 1927, or nearly a hundred years ago. Photo by Bob Dryja
Picture 3B: This picture shows the writing in Picture 3A in red. Photo by Bob Dryja
There are a small number of exceptions to the letter and number carving done for dendroglyphs. A carving of a horse head is one example (see picture 4). The outline of a house is in a second example (see picture 5). A carving of a cross is in a third example (see picture 6). A possible sketch of a sheep is shown in picture 7.
Picture 4: A side profile of a horse head is carved in a grove of aspen trees that otherwise only show words and numbers. Photo by Bob Dryja
Picture 5: The outline of a house is carved. Note that it shows both the side and front sides. Photo by Bob Dryja
Picture 6: A cross is carved above a set of letters. The letters "B, V and N" can be seen below the cross but what do these letters stand for? Photo by Bob Dryja
Picture 7: A side view of a sheep with horns may be represented in the lower half of the picture. The cursive writing of a word is shown above the sheep image. Photo by Bob Dryja
Picture 7: A side view of a sheep with horns may be represented in the lower half of the picture. The cursive writing of a word is shown above the sheep image. Photo by Bob Dryja
Documenting dendroglyphs now is important. Aspen trees with carvings are reaching the end of their lives. Many are loosing their bark or falling in broken pieces. A research program presently is searching systematically for dendroglyphs. A dendroglyph is photographed and drawings made of it. The tree location and its condition are recorded. The actual dendroglyphs may be lost in coming years. However their images are being recorded for future analysis.
