Archeological Report

Archeological Reports

2025 Geophysics Study – Ground Penetrating Radar: Download

2024 Report of Tree Ring Dating of Stone House: Download

2023 Stone House Cultural Resource Survey: Download

2023 Stone House Survey Map: Download

Report of Tree Ring Dating of Stone House
In the Spring of 2024, the author was approached with the task of dating the Campo/Sanchez stone house located at 12010 State Highway 10, north of Tijeras, NM (Figure 1). This structure was wanted for use by the East Mountain Historical Society. The Society desired to know the building history before any renovations or other work with the structure were conducted (see East Mountain Historical Society 2024). In its later years, the building was encased in later slabs of vertical stone covering the exterior. The stone building consists of two primary single-story rooms (Rooms 1 and 2), along with a third unnumbered room built above a basement room (Room 3; Room 4 in the EMHS 2024 document) on the southeast side, which is now too dangerous to access because of rotted flooring. There is also a former roofed room as part of the southeastern side of the overall building, not numbered for this wood project (but Room 3 in the EMHS 2024 document), but its roofing had been removed and the walled space left open to the skies. A storage room entered via the southwestern wall doorway from subterranean Room 3 existed under the flooring of this un-numbered room (i.e., EMHS 1st-story Room 3) that is missing its roof.

Aside from much milled lumber present in the structure that infers more recent renovations, the two main rooms are roofed with primary beams, or vigas, to support the plank and board-covered ceiling vigas. These ceilings are now under a pitched rafter roof of boards covered by asphalt shingles. In the 1800s and early 1900s, trees for construction were primarily cut either with a steel axe or were sawn down. As metal became more readily available after the opening of the Santa Fe Trail by William Buckner in 1821 via San Miguel de Vado (Windes 2011), a village along the Pecos River, axes were slowly replaced by hand saws and later saw mills, especially after the railroad entered New Mexico in 1881.

The first mill in the region reportedly was built by the U.S. Army in Santa Fe in 1850 (Mather and Woods 1986:102; Windes 2002), although other private small, perhaps family-owned mills may also have been present by then, if not somewhat later. The Sandias were a source for much lumber over the centuries but the earliest mill(s) may have been operated only by the late 1800s, when several small mills existed along the eastern side lower reaches of the Sandias. The rectangular planks covering the vigas in Room 1 are rough and saw cut, and could be contemporary with the dating of the vigas, whereas the planks/boards covering the Room 2 vigas are smoothly milled and probably are coeval with its later vigas.

Overall, milled wood was used as early as when the first construction started, although it was expedient for almost everyone building homes to hand ax-cut local ponderosa pine for their vigas and to use various metal tools to strip off the bark, during any season. Prying off the bark during the early spring preserves the beam’s original round form when bark removal is relatively easy without the need of cutting tools. Given the crudeness of the bark removal for the house vigas, which removed large swaths of the outer growth rings along with the bark especially in Room 1 (Figure 2), suggests that the work was done by an inexperienced and/or hurried worker or workers.

Room 1 (450 by 694 cm; ceiling height 274 cm). The 21 vigas in Rooms 1 and 2 differ considerably from one another. Room 1’s beams (field specimen [FS] 1-11) appear to be the oldest, with the eleven dark (aged) beams exhibiting maximum diameters generally exceeding 20 cm in diameter (mean 23.3 cm diameter). The ring counts from these are lengthy, often over 100 rings (Table 1), but widely varied as to overall tree age at the time of cutting. This suggests local procurement within in an area dominated by older trees that were eventually eradicated for use in construction as the population increased.

Based on limited observation in both rooms, the beam ends had been axed or adzed roughly flat, eliminating the common “beaver-tail” projection (Morris 1919:44, Windes and McKenna 2001: Figure 4). This indicates that the tree fell before complete ax-cutting of the tree stem could be accomplished. None of the visible ends had been saw-cut. Most beam ends were not visible (“NE,” Not Exposed, in Table 1), but hidden in the walls. In a few instances beam ends from these two rooms could be observed in the wall, where they were set next to one another.

On visible evidence, alone, I would place Room 1 as the older of the two rooms, which tree-ring dating confirms as being built in 1888 or shortly afterwards (see Table 2 for analyst codes for the innermost and outermost growth rings for a sample). These codes provide the analyst a confidence level of the observed outer-most growth ring condition and, thus, the date.

Room 2 (390 by 760 cm; ceiling height 260 cm). Beams in Room 2 (n=10; FS 12-21; all were sampled) were lighter in color and markedly smaller in maximum diameter (mean 19.3 cm diameter; Figure 3) than those in Room 1. By the time Room 2 was built, beam sourcing, although probably still relatively local, had relied upon secondary pine growth of much younger aged trees. By then, probably most of the lower elevation older ponderosa pines in the area had long been cut for construction and other needs.

Room 2 revealed that all of the beam sample dated in 1932. These also revealed an “incomplete” outmost ring, indicative of harvesting during the tree growing season. With ponderosa pine, which varies slightly by region, growth starts in the Spring, perhaps as early as April or May and lasts until about September. If the outermost growth ring is “complete,” then it can be determined that the tree ceased growth during the Fall after September or so of the dated year, but may have been cut as late as the spring of the following calendrical year around March or April before growth started again.

If a cluster of dates, such as from Room 2, produces most but not all “incomplete” outer-ring dates and perhaps a very few “complete” outer ring dates, then it can be interpreted that the group was probably cut during a single episode late in the summer of the dated year. In Room 2’s case, however, all of which revealed an “incomplete” outermost ring, we can only interpret that the beams were all cut during the summer of 1932, probably during a single episode. Analyst Tom Swetnam (Appendix 1) noted, however, that most of the growth in the outermost growth ring had taken place in the middle and late summer, indicative of Fall harvesting.

Swetnam further noted that the majority of the Room 2 vigas (7 of the 10 that dated) were missing the growth ring for 1904, evidence of a small stand of trees being harvested affected by similar environmental conditions:

All of the dated vigas from Room 2 have cutting dates of 1932. The 1932 ring is incomplete but includes what appears to be most of the earlywood formed for that year, suggesting a middle to late summer harvesting. Although five of the viga samples from Room 2 have fewer than 50 rings, it was possible to crossdate these because it appears all trees were from the same forest stand and they all share many similar false rings, latewood width, and coloration features that enable crossdating.

Room 3 (389 by 505 cm; ceiling height of 203 cm). Results from the subterranean Room 3 are less certain, in part because only a very few samples were taken. The joists for this room (FS 24-31) were all milled 2 x 8 inch vertical rectangular planks, smoothly cut and clearly built later than Rooms 1 and 2. Only a single joist was sampled (FS 24), but its sparse 49 rings failed to date. These sawn joists will not produce cutting dates, but can provide dates that are certainly later than 1932 and, if enough are sampled, could produce a cluster of similar dates that roughly approximate the harvest date for the original timber(s).

Above the southwestern doorway in Room 3 that entered into a storage room of some sort with some walls of dirt, a large rectangular 18 x 19 cm adzed beam (FS 22; i.e., an early beam) served as one of several wood elements above the doorway as part of the door-lintel complex (Figures 4-5). Because it has squared corners (removing perhaps all of the outer growth rings), it was unlikely to provide a cutting date for the project. But the inner most side, difficult to see and to access, had apparently a shallow swale along it, which I interpreted as a possible outer surface. Thus, I took two samples (FS 22a, b) from the beam’s opposite sides, hoping for something close to the outermost growth ring for when it was cut.

Surprisingly, the two samples not only dated, but were only a year in difference for the dates. The two cores together produce a date of 1766p – 1878+vv. Although I called the outer ring in the field “vv” (a non-cutting date), I was leaning towards a near-cutting date (“v”) based on feel, but it was hard to see the sampled smoother (original?) side that was mostly obscured by other elements. This element could be part of the 1880’s period of construction (i.e., Room 1) but it is uncertain why it is in the later basement far from Room 1. Does it represent some 1870s/1880s construction in situ or is it perhaps a reused element from some earlier part of the house? Its unusual in shape and large in size for its present use. Its initial use is uncertain and from where in the construction it might have been placed originally. Given its shape and size, it might have served as an original lintel over a doorway or window, perhaps in Room 1, although it is much larger than normal. A beam of this size has been commonly noted within New Mexico mission church constructions (e.g., Windes and McKenna 2006) and in walls and porch roofs in Territorial structures (e.g., Bunting 1976:89-93).

Sampling Strategy
Generally, we try to sample about 50 percent of the total potential sample of the roofing elements and any embedded wood elements in the walls and under the floors. In this case, because of the viga size and subsequent lengthy ring series counts that we made after the first of two sampling sessions (30 June and 8 August) at the Stone House (having later sanded the core sides to examine their ring patterns), I subsequently took 7 of the 11 vigas (64%) in Room 1.

The much shorter ring series common to small-diameter vigas, less likely to date, collected for the initial sampling in Room 2 indicated that taking nearly all of the Room 2 vigas might help to produce at least a few dates. This decision turned out to be a good one in that two of the Room 2 vigas exhibited lengthy ring series of 67 and 86 rings, which were keys to dating all of the Room 2 vigas that had much shorter ring series (mostly less than 50 rings). Normally, these probably would not have been tree-ring dated. Overall, we sampled 81 percent of the vigas in Rooms 1 and 2.

Thus, in both rooms, the sample is such that we can interpret with confidence the dates when the trees were harvested for construction for the two rooms, as being approximately 44 years apart. In normal circumstances, the harvest dates indicate the year or shortly afterwards the year(s) that the structure was built. In this case, it does not suggest beam stockpiling for later construction because the harvest dates do not spread over a range of years.

Miscellaneous Notes

Drill samples are typically collected with a specially made 5/8″ diameter hollow drill bits (other possible work sizes are 1/2″ and 7/8″ in diameter), primarily from the larger end of the two beams ends in order to obtain the maximum number of rings present. The core holes are then plugged with maple wood plugs (glued in with exterior wood glue) and stamped with the FS number.

I try to document all the architectural wood (every piece) unless it is milled lumber (pitched roof rafters, window/door frames, etc). The sample holes do not damage the structural integrity of the structural wood. Anything of wood ideally can be sampled for tree-ring dating, even the wooden irrigation logs, wagons, wagon axels, milled lumber, etc., providing they are of datable Southwestern species (primarily ponderosa pine, Douglas-fir, piñon, and sometimes some species of juniper and other spruce-firs, such as blue spruce and white fir).

Cottonwood/willow/sycamore elements will not date. They are closely associated with water and therefore are less impacted by changing environmental conditions and, thus, will not be sampled unless I don’t recognize them at first. Beams that have been shaped, including debarking with draw knives (common to worked Hispanic vigas), will not provide cutting dates but can provide a “no earlier than” date. Sometimes, however, a poor debarking job can yield patches or strips of outside ring material, including bark, as in this case for both Rooms 1 and 2.

Conclusions

The tree-ring evidence indicates that there were at least two major construction episodes for the building in about 1888 and again in 1932 (Table 1) with the construction of Rooms 1 and 2. Subsequent later additions, however, have not been dated with dendrochronology and it would be difficult to do so using dendrochronology given the reliance after 1932 on milled rectangular-shaped elements for the newer additions and modifications. The large beam in the doorway of Room 3 is somewhat of an enigma. Its dates suggest that it may have been a dying tree when it was cut and that an unknown number of outermost rings are missing, but given the Room 1 dates and the two lintel dates being so close together, it probably was cut during the 1880s when Room 1 was being constructed or whatever other associated buildings may have been built there.

Acknowledgments
My many thanks for the able help provided by Jo Lynne Fenger, Christine Gilbertson, and Philip Leckman during the tree-ring sampling and documentation.

References
Bunting, Bainbridge
1976 Early Architecture in New Mexico. University of New Mexico Press, Albuquerque.

East Mountain Historical Society
2024 Stone House-Sanchez/Campos – Integrity Report. Unpublished ms., East Mountain Historical Society, Tijeras, NM.

Mather, Christine, and Sharon Woods

1986 Santa Fe Style. Rizzoli International, NY, NY.

Morris, Earl B.
1919 The Aztec Ruin. Anthropological Papers of the American Museum of Natural History, Vol. XXVI (Part I). American Museum Press, New York.

Swetnam, Thomas W.
2024 Tijeras Stone House, New Mexico, Tree-Ring Dating Report. Unpublished ms., possession of the author, Jemez Springs, NM.

Windes, Thomas C.
2002 1,100 Years Of Construction Wood Use in the Upper Pecos Valley. In From Folsom to Fogelson: The Cultural Resources Inventory of Pecos National Historical Park, Vol. 2, edited by Genevieve N. Head and Janet D. Orcutt, pp. 501-644. Intermountain Cultural Resources Management Professional Paper, U.S. National Park Service, Santa Fe.

2011 A Dendrochronological Study of Nineteenth-Century San Miguel del Vado and San José del Vado in Northwestern NewMexico. New Mexico Historical Review 86(4):461-489