GLO Survey Notes

Tabular Summaries of Original Land Survey Tree Data

in the Shoestring Research Area

The folowing two tables summarize General Land Survey (GLO) original land survey notes for a six square-mile area in Douglas County, Oregon that includes the "Shoestring" BLM forest study plots (see: Index Map). There are a total of 87 identified and measured trees in this summary, including "line" trees, and Bearing Trees on adjacent areas that are used to locate section corners and quarter-section markers.

It is assumed that all trees designated "fir," "laurel," or "madrona" by the original land surveyors are madrone or Douglas-fir. Similarly, it is assumed that all "pine" are Ponderosa pine, although sugar pine also exist locally. Black oak and white oak are clearly identified, as are chinquapin and canyon live oak. However, a "c. oak" and a "pine-oak" remain unknown, and are simply considered as "oak-types" in Table 2. A review of subsequent survey data or historical aerial photographs should help clarify specific species' designations.

Table 1. lists the year of the survey, the number and species of trees recorded, the page reference (and therefore, location and surveyor) of each surveyed tree, and places the trees into one of four diameter classes: 1) Bearing Trees less than 10" in diameter are assumed to be relatively young, juvenile trees -- although a 9" oak is almost always much older than a 9" Douglas-fir; 2) Bearing Trees 10-inches to 19-inches in diameter are assumed to be young second-growth; 3) Bearing Trees 20-inches to 30-inches in diameter are assumed to be merchantable (although not particularly large, especially for conifers) second-growth; and 4) Bearing Trees larger than 30-inches in diameter are considered "possible" old-growth (in excess of 200 years old), although are likely to be much younger.

Juvenile trees measured in the 1850s can be considered to have germinated sometime in the early 1800s, and the youngest trees (3"-6") sometime after the human plagues of the mid-1820s and early 1830s. Juvenile trees measured in the 1870s and 1880s may be related to local disturbances caused by mining activities and associated grazing by pack animals. Only two of the 87 trees are in excess of 30" in diameter, both are conifers, both are 36" diameter, and both represent the relatively small number of measured trees that may have germinated before 1750. The two 14"-diameter yew trees, or perhaps a few of the larger oak or madrone may be of a similar age class, but the large majority of survey trees appear to have germinated sometime after 1775. There is no evidence of anything more than a few isolated trees of any great age, and certainly no major stands, strips, patches, or pockets of old-growth appear to have existed in the study area at any time during the past few centuries. Also, Douglas-fir and madrone, in addition to being the most numerous species on the landscape, also appear to be the most evenly distributed.

Table 2. summarizes the data from Table 1. by total numbers of species in each diameter class. There is nearly an exact 50/50 split between conifer and hardwood trees, and nearly 1/3 of each group includes juvenile 3" to 9" diameter trees. There are no apparent old-growth, and only 1/7 of the hardwoods are 20" or larger in diameter. A fairly young, likely invasive, forest of multiple conifer and hardwood species, but mostly Douglas-fir, oak, and madrone. No particular evidence of past ancient forests, or of stand replacement wildfire.

Table 1. Summary of named Bearing Tree species and diameter classes of study area.

Table 2. Summary of species types and diameter classes for study area.

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