As a fuel for cooking and processing food, as a source of heat in times of cold weather, and (along with green vegetation) as a source of smoke for rituals and to repel insects, firewood was used daily and probably was collected daily as part of the foraging strategy. Small saplings and woody shrubs were also used in constructing huts and other shelters; other types of wood were used for bows, tool handles, and grinding containers (i.e., mortars). These uses of wood were important but not as critical as fuelwood, which is the focus of this section.

 

Firewood is a resource that is unconditionally required and difficult to transport, and its availability likely played a key role in determining site location. Tremendous amounts of wood were necessary for cooking plant roots, bulbs, and tubers (geophytes). Given that food resources such as deer, geophytes, and mussels are potentially abundant or available at relatively low costs throughout the lower Bosque basin, could firewood have been the crucial factor for determining the length of site occupations? As nearby sources of wood ran out, more and more time would have been spent gathering wood from greater distances from camp, taking away time that could better be devoted to other tasks. When firewood became depleted, the campsite would have to be abandoned.

 

Various factors affected firewood use decisions. In their 1988 review of the ethnographic accounts, Tristine Smart and Ellen Hoffman noted heat yield and quantity of smoke produced, as well as availability and ease of collection as being prime considerations. Firewood collectors preferred fallen trees and dead or fallen limbs, which are lighter and burn readily because they are drier. Because not all trees are natural pruners, this strategy affects the taxa that are collected and burned. When dead wood is no longer available, live trees or young saplings may be cut for fuel. This can be viewed as a product of the duration of site occupations or use intensity.

 

Charred wood remains of various taxa were recovered from features and nonfeature contexts at the Britton, McMillan, and Higginbotham sites. Nearly all are arboreal species that are found today throughout the riparian corridor of the North Bosque River. The prehistoric hunters and gatherers did not discriminate against any species of wood, probably collecting all manner of dead limb wood in the site areas—a collection and use process that researchers David Asch and Nancy Asch refer to as the “Firewood Indifference Hypothesis.” This hypothesis suggests that low collection costs dictate the use of the nearest available deadwood. Based on the charcoal recovered from the Britton, McMillan, and Higginbotham sites, the nearest available wood primarily would have been oak, pecan, and elm and elm family species. Boxelders, plum/cherry species, ashes, and sycamores were present in smaller amounts. Not all of these taxa were present at all three sites; for instance, sycamore, boxelder, and elms were not present in the Higginbotham assemblage, and elms and sycamores were not present in the McMillan assemblage. Their absence most likely reflects the local environment rather than any kind of choice made by the site occupants. Oak and pecan charcoal are the dominant taxa in the Britton and Higginbotham assemblages and at the McMillan site, save for Analysis Units 2 and 3. Analysis Units 2 and 3 at the McMillan site yielded large amounts of possumhaw/yaupon.

 

Oak and pecan trees are natural “self-pruners,” frequently dropping branches and providing considerable amounts of dead limb wood for firewood collectors. It is not surprising, then, that they are the dominant taxa in the charred wood assemblages. The lack of heavy wood chopping or cutting implements such as celts and axes in the tool assemblages supports the notion that the most common fuel used for fires was fallen limbs. Again this suggests that firewood collection and use at the sites was an issue of availability and cost. The large amount of possumhaw/yaupon in the charred wood assemblages of Analysis Units 2 and 3 at the McMillan site is interesting. Although present in the site areas (and present only in small amounts in the charcoal assemblages at Britton and Higginbotham), these holly species, unlike oaks and pecans, are small and are not natural pruners. This suggests that possumhaw/yaupon trees were purposely cut for firewood once collecting fallen limb wood became costly. Possumhaw/yaupon trees are small enough to be felled with small hafted bifaces; larger stone celts and axes would not have been required. This also suggests that the occupations represented by Analysis Units 2 and 3 at McMillan were relatively lengthy, since all of the easily accessible dead limb wood had been consumed.

 

Supporting this idea of accessible firewood depletion is the presence of charred juniper, an upland species, in Analysis Units 2 and 3 features. Depletion of easily accessible fallen limb wood also may have occurred during the occupation(s) represented by Analysis Unit 1 at McMillan. Charred wood from plateau live oak, another upland species, is present in large amounts in Feature 6. In fact, over 68 percent of the plateau live oak charcoal recovered from the McMillan site comes from Feature 6. Granted, access to upland environs around the McMillan site for the collection of firewood was easy and distances were short, but this was certainly not less costly than gathering fallen limb wood on the floodplain surrounding the site.

 

The depletion of easily accessible firewood seemingly occurred at the Britton site as well, as woods of upland species were collected and burned and some possumhaw/yaupon was used. Half of the oak charcoal at Britton is identified as plateau live oak, and most of it (65 percent) comes from three features in Analysis Unit 2. The charred remains of another upland tree species, mesquite, was recovered from one feature in Analysis Unit 1. At the Higginbotham site, depletion of easily accessible limb wood on the terrace surface surrounding the site seemingly did not occur. Only 10 pieces of plateau live oak are present, about 20 percent of all oak charcoal identified at the site. No other upland or nonriparian species are present in the charred wood assemblage.

 

Charred wood assemblages at the Britton and McMillan sites indicate that easily accessible firewood from the surrounding floodplain and terrace surfaces were at times depleted, and that occupants resorted to cutting small trees close to the sites or ventured into the surrounding uplands for dead limb wood. Either scenario suggests that firewood, particularly easily accessible dead limb wood, was often exploited beyond a sustainable level. Components that show signs of overexploitation indicate relatively lengthy occupations or high use intensity, but at some point the acquisition costs must have increased where site abandonment occurred.