These methods, instrumentation and/or protocols apply to all data in this dataset:| Methods and protocols used in the collection of this data package |
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| Description: | Macroplot layout: Each of the seven sections of the macroplot (A-G) is a rectangle with corners at the center of four adjacent plot centers in the larger and preexisting network of continuous forest inventory (CFI) plots (see other data packages and references). CFI plots are separated in N-S 'columns' by 2 chains = 132 ft = ~40.24 m, and columns are separated in E-W direction by 5 chaines = 330 ft = ~100.58 m. Thus each rectangular section is approximately 100x40 m (long dimension E-W); these dimensions are only approximate due to unit conversion and because the original surveying and establishment of CFI plots ca. 1932 apparently accumulated some error. These errors and approximations are incorporated as fully as possible in calculating overall map coordinates in the data archived here.
Section A is defined by CFI plots 4862 (NE corner), 4861 (SE corner), 4860 (SW corner), and 4859 (NW corner). Section B is immediately south of Section A; Section C is immediately north of Section A; and Section D is immediately north of Section C. Section E is directly W of Section A (corners at CFI plots 4860, 4859, 4841, and 4842), Section F is north of Section E (W of Section C), and Section G is north of Section F (W of Section D).
Each Section was subdivided into grid cells for mapping purposes. First, 100-m lines were established running E-W at 10 and 30 m S of the northern edge of a Section (these define the 10 and 30 coordinates in the "Short" or N-S dimension of each Section). Along each of these lines, 'mapping cell' centers were defined every 20 m at 10, 30, 50, 70, 90 m ("Long" or E-W coordinate) measuring westward from the E edge of the Section. Thus, each Section is divided into 10 approximately 20x20 m sections. Because of irregularities in the original surveying of CFI plot locations, the western-most cells of each E-W line of mapping cells varied from as little as 14 m to about 25 m (in some instances the center of mapping-cell was placed at 95 m "Long" coordinate rather than 90 m). In general, the southern line of mapping cells in each Section ("Short" coordinate = 30) were about 20.6 m in N-S dimension to accomodate the 2-chain distance between CFI plots.
To faciliate recognition of the edges of mapping cells and their relocation, PVC pipes (ca. 1 m long) were placed as stakes at corners and approximate half-way points for all mapping cells as well as at cell center, creating an approximate 10x10 m grid of stakes throughout the macroplot.
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| | Description: | Initial measurements, 1993-1995: All woody stems > 2 cm diameter at breast height (DBH: i.e., at 1.4 m above average base of trunk) were mapped and measured in 1993 (Sections A-D), 1994 (Section E), and 1995 (Sections F, G). DBH was measured by diameter-tape for stems > 5 cm dbh and by caliper for stems 2-5 cm dbh. Stems were mapped on polar coordinates within each mapping cell; azimuth from cell center was measured in degrees east of magnetic N using Suunto "sight-through" compasses, and distance was measured using Sonin sonic range-finders. Dead trees > cz. 15 cm DBH were recorded along with notes as to state of decay; in some cases identification to species was not possible for dead stems. Stems >5 cm DBH were tagged at 1.4 m with aluminum tags with stamped numbers.
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| | Description: | Recensuses, 1999-2019: Beginning in 1999, a complete recensus of the entire macroplot was conducted every five years (through 2019 so far). All trees previously mapped and recorded were remeasured for DBH. New recruits - stems having reached 2 cm dbh since the last census - were recorded, measured, and mapped, and trees dead since the last census noted. Information as to nature of mortality and state of decay was recorded for dead trees; manner of death was noted as either 'standing dead' (most of the main bole intact), 'tip-up' of 'T' (uprooted), or 'break' or 'B' (trunk broken below crown or low enough to result in death). Numerical codes indicating state of decay were recorded as 0 (freshly dead; leaves attached), 1 (fine twigs remaining, no evident decay), 2 (small twigs mostly gone; some bark may be detached), 3 (beginning to lose bark, only larger branches remaining). Higher codes indicating more advanced decay were rarely applicable where mortality was within last 5 years. For broken trees, the code typically included an estimate of the height of break (e.g., "1-B-3.0" means decay class 1, broken at 3 m). Other descriptive notes described status of trees that were damaged, appeared sick, or had other traits worth noting.
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| | Description: | Subsequent calculations: The data table in this package includes some variables calculated from the initial measurements described. Specifically, polar coordinates were converted into Cartesian coordinates within each mapping cell, where the cell center is the 0,0 coordinate and N and E are positive X and Y directions. A Cartesian coordinate system was established for the entire macroplot, and coordinates for each tree stem calculated taking into account all known irregularities in the mapping-cell grid (described above). In this system the origin was the northwest corner of Section A, or the center forest inventory permanent plot 4859. X coordinates ranged from W (negative) to E (positive, and Y coordinates from S (negative) to N (positive).
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