How do you make use of a tree that does not sprout? Most conifers don’t sprout from cut limbs or from the base. When you have cut a branch or a bole, that is the end. The ancestral Puebloans of the American Southwest did not have much to choose from. They used a little wood from broadleaf trees—cottonwood and aspen—but mainly a suite of conifers: ponderosa pine, Douglas fir, juniper, pinyon pine, spruces, and firs. The evergreens were stronger and lasted much longer. The people needed firewood. They also needed wood for roof beams and for lintels, at least. The wood needed to be straight and as little knotty as possible: from four to twelve inches in diameter and from eight to twelve feet long.
How were they to get this wood from trees that would not sprout again once cut? A great deal of it they simply harvested by removing young trees at the appropriate diameter using the revolutionary sharp Neolithic stone axe, which could make a kerf in a log, not just bludgeon dents. Many stems were likely cut this way, and for firewood, they might harvest only deadwood. Because their conifers didn’t sprout back except from seed, however, the people might more easily denude their landscape.
Late in the history of the Mesa Verde cliff dwellings, at least, by imagination and observation, they found a possible solution. All trees and shrubs, conifers or not, share a peculiarity. If you bend a stem over from the vertical toward the horizontal, you will release whatever dormant buds are alive near the surface of the stem, and any lateral branches that have already sprouted will change their minds. Instead of becoming laterals, each will try to become a new young tree, re-creating the pattern of the original tree. These newly released stems will grow straight and true, just as though they were saplings. This is the process of phoenix regeneration (see page 51).
Someone at Mesa Verde saw this happen, maybe in a Douglas fir that had been knocked over by a falling branch or fallen in a storm. They decided to try it intentionally. Scientists during the 1960s looking for the oldest Douglas firs in the Mesa Verde area in order to complete their dendrochronology came upon a series of very old specimens that had apparently been intentionally bent over almost flat—centuries before, when they had still been young trees. Intriguingly, each of these ancient trees had wounds on top of the bent stems that seemed to have been made by stone axes.
The people in the late phase of Mesa Verde building—only a few decades before the place was abandoned—apparently had turned lateral branches into straight new young trees. They were thus able to harvest straight poles for lintels or roofs without destroying the tree. When they harvested the dominant reiteration, the next strongest would become the dominant stem and would increase its rate of growth, eventually providing the next pole. Because they were dendrochronologists, of course, the scientists were expert at reading the width of annual tree rings. They noticed that there were periods when a stem suddenly increased dramatically in its ring widths, without any climate events that might have caused the change. The increase, they believed, was caused by the stem’s becoming the new dominant on the flattened trunk.
Once cut, the stem had to be debarked to create a smooth pole. It was very hard to get the bark off Douglas fir, even in spring when the bark is at its loosest. The carpenters learned, however, that if you cut the wood when the bark beetles were in flight and left the wood around for a few weeks, the beetles would get into it and loosen the bark for you. Then, the bark was more easily removed. Some pole wood in the ancient Puebloan sites showed the characteristic larval galleries made by bark beetles.
Brilliant ideas indeed, or rather brilliant observations, but they were too little and/or too late. It is notable that at the end of the Mesa Verde occupation, house lintels would be made or repaired with stones, not wood. The three ancient trees that had been tricked into reiteration stood on a very steep and difficult-to-access talus slope. Although nobody knows exactly why the cliff dwelling was abandoned, it is very possible that a shortage of wood was among the reasons. The Puebloans had built and cooked themselves out of house and home. However, they did not simply disappear. Rather, they moved to mesa-top sites near more well-watered and wooded bottomland, where pinyon pine and juniper were thick and accessible.
All of the southwestern tribes—including the Navajos, the Puebloans’ rivals for more than five hundred years in the same landscape—had a similar need to respect scarce wood and to use it sparingly. The term Anasazi, the word once usually used to name the ancient Puebloans, is now little spoken because it is a Navajo word that means “our enemies.” The Navajo had a specific way to preserve the trees out of whose wood they made cradles. Thus, the tree served both physical and spiritual needs, since the tree’s long life was wished upon the baby.
The father typically made the cradle. He would find a tall straight tree. Some say ponderosa pine was the preferred wood, though juniper and other woods were also used. The tree had to be broad enough to be able take a piece from it without harm to the whole. It had to be healthy and not have been struck by lightning. It had to be in an out-of-the-way place where the tree was unlikely to be harvested. The father would make two transverse cuts on the east side, the sunrise side, and split out a three-foot-long section of the trunk.
Sometimes, when he was done, he sang this song:
I have made a baby board for you, my son,
May you grow to a great old age.
Of the sun’s rays I have made the back . . .
Of rainbow I have made the bow . . .
Of sundog I have made the footboard. . . .
Since the wood’s making was the result of sun-driven, rain- and air-mediated photosynthesis, the statements were not inaccurate. The tree would close the wound again, continuing to grow as before. The making may indeed have expressed a wish to borrow the long life of trees and their resilience when damaged.
Interestingly, it was often the trees themselves whose lives were extended by respectful human treatment of them. When scientists discovered those ancient Douglas firs at Mesa Verde, they were not looking for human-influenced wood. They just wanted a tree old enough to complete their chronology, but they could not find one. They had the tree-ring patterns of the ancient wood from the buildings and they had the tree-ring patterns of still living trees. They looked and looked for specimens that would bridge the gap between the dead and living trees. Their archaeological chronology came up to AD 1275. The oldest they could find in a living tree was AD 1285. Close but no cigar. They were ten years shy of completing the chronology.
A year later, a park ranger found what he thought was a very old tree. He took a tree-ring core sample and sent it to Edmund Schulman, one of the dendrochronologists. Schulman was back on site in a flash and took twenty-six more cores from the same tree. It turns out this Douglas fir first sprouted in AD 1170. He had completed his chronology with more than a hundred years to spare.
Not until sixteen years later, in the course of preparing a museum exhibit, did students notice that this tree had had a section cut in prehistoric times with a stone axe. They then found the two nearby trees that had likewise been bent and subsequently had a reiterating stem removed. The eight-hundred-year-old tree that had completed the chronology was a tree that had been cultivated and cut by human beings. The human use of the tree had not shortened its life; it had lengthened it.