Southeast Alaska old-growth forest stem map data collected in 1964 on ten 1.42 hectare plots

Metadata:

Identification_Information
Data_Quality_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification_Information:

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:: Data have been checked for accuracy. Attribute accuracy is detailed in LaBau (1967).

Logical_Consistency_Report:

Data have been checked for logical consistency.

Completeness_Report:

no missing data

Lineage:

Methodology:

Methodology_Type: Field
Methodology_Description:: A study plan was prepared and approved in the spring of 1964. A field manual was written to accompany the study plan and preliminary test runs of field techniques were made (\Supplements\3_Manual_of_field_instructions.pdf).

PLOT SELECTION

The size of the field plot was set at 3.5 acres (5 x 7 chains) to avoid the possibility of bias due to the computer sampling missing qualifying trees which fell outside the field plot. Preliminary study indicated that when sampling from the Forest Service basic 10 point cluster pattern with a 20 basal area factor, an area of at least 3.5 acres was needed to provide a buffer zone for computer sampling. This buffer zone would assure that no trees which should be counted at a given point were beyond the boundaries of the field plot.

The 3.5 acre plots were selected from photo centers of 1963 aerial photography (1:15, 840 scale) of an area surrounding Juneau, Alaska. Two plots were selected near Petersburg to get a measure of heavier volume timber which was not indigenous to the Juneau area.

Ninety-two aerial photo centers from coverage of the study area were examined. Certain restrictions had to be met before a photo center point qualified for the sample draw. The forest type associated with the photo center had to be as follows:
accessible--less than one mile from beaches or roads
commercial--forest land capable of producing 8000 board feet per acre (net)
old-growth--more than 150 years old
spruce and/or hemlock forest
five acres or larger--each area had to be large enough to accomodate a 5 x 7 chain rectangular plot

All photo centers meeting these requirements were classified into either the medium density class (40% to 69% crown closure) or the full density class (70% to 100% crown closure). Moessner's crown density scales (1949) were used as guides for this classification. Originally, the plan called for sampling poor density stands. However, none of the photo centers falling on poor density types qualified as commercial forest land. Twenty-six of the photo centers examined qualified for sampling, only five of which were medium density stands. All five of the medium density points were selected for field measurement. Five of the twenty-one full density photo center points were randomly selected for field plots.

FIELD PROCEDURES

The photos selected for sampling were used with standard Forest Survey procedures to locate the field plots. The photo center point was located in the field, and this served as the initial point of the 3.5 acre field plot. The field plot was oriented at 00 if this orientation placed the entire plot within the forest type as interpreted on the photos. If not, second, third, and fourth choices of plot orientation were 180°, 90°, and 270°, respectively. Provisions were made for going beyond this, if necessary, but are not presented here.

After orientation, the boundary control was laid out. From the initial point, a line was run for three chains on a bearing opposite to that of plot orientation. From this primary control point, boundary lines were run around the plot using a staff compass, topographic chain, and relascope. These lines were marked with string. The four corners of the plots were staked and witnessed. Secondary control points were established along the narrower sides of the plot. These were located at one chain intervals from the plot corners. These secondary control points would be used later to subdivide the plot into five corridors one chain wide and seven chains long. As the boundary lines were laid out, records were kept of tree diameter and location for all trees 37 inches diameter at breat height (DBH) and larger which fell less than one chain outside of the plot boundary. These were trees which would demand consideration when making the final decision of what minimum basal area factor would be used in the computer simulation program.

The maximum error allowed in closing the traverse on the primary control point was 1 in 300. If this closure was not attained, the source of error was determined, and the boundary lines were corrected.

The plot was then subdivided into five corridors one chain wide and seven chains long. These corridors were separated by string lines which were tied in at each end with the secondary control points which were established when the exterior boundary was traversed. The plot was then ready for stem mapping. The stem mapping was done in subplot units of one-tenth acre, following this pattern:
35 22 21 8 7
34 23 20 9 6
33 24 19 10 5
32 25 18 11 4
31 26 17 12 3
30 27 16 13 2
29 28 15 14 1

A steel tape, corrected for slope, was laid down the middle of subplot one and staked semipermanently. The head chainman staked the zero end at the upper end of the plot, and the rear chainman staked the corrected tape reading at the subplot initial point. All trees 3.0 inches DBH and larger were stem mapped, progressing up the left side of the subplot and back down the right side. One crew member moved up the center line, sighting from a hand compass set +90° to the subplot centerline. As his compass sight intersected trees, he plumbed the point on the center tape. This distance, uncorrected for slope, was recorded as latitude distance for the tree. A second taped distance from the center line to the center of the sighted tree was recorded as longitude distance. A zero was recorded as the first digit of the longitude distance code for all trees to the left of the center line. If the tape could not be leveled from the center line to the tree center, a slope reading in degrees was recorded as longitude degrees, and the uncorrected slope distance recorded. A 00 code was recorded for longitude degrees where level distances were measured. Each tree on the subplot also received a latitude degree code to indicate the slope of the centerline. These slope distances were later corrected to level distances by the computer program. Other information coded for each tree included tree number, species, DBH to the tenth inch, and log height in 16 foot logs to a merchantable top. Five species were recognized. They were as follows:
1. Sitka spruce Picea sitchensis (Bong. ) Carr.
2. Western hemlock Tsuga heterophylla (Rafn.) Sarg.
3. Alaska-cedar Chamaecyparis nootkatensis (D. Don) Spa ch,
4. Black cottonwood Populus trichocarpa Torr. and Gray.
5. Red alder Alnus rubra Bong.

After the left side of the subplot was mapped, the crews progressed back down the right side. The same information was recorded, except that a minus preceded all coded longitude distances for trees mapped on the right side of the subplot. Upon completion of subplot one, the centerline tape was moved to the second subplot. There, it was again staked down semipermanently, using the endpoint of the first subplot as the starting point of the second. This was repeated for all 35 subplots. To avoid wasted motion, subplots 8 through 14 and 22 through 28 were mapped in a reverse direction to that of the other 21 subplots. The same codings were used to designate trees to the left or right of the line. This, at first, appeared to present a problem when applying grid coordinates to these trees for use in the computer sampling program. This problem was resolved with less trouble than anticipated.

Occasionally, because of brush or rough terrain, the mapping could be done for only 33 feet of the subplot at a time. Application of slope corrections for the last 33 feet required handling the centerline distances slightly differently to keep these readings consistent with the normal centerline readings.
Methodology_Citation:
Methodology_Citation:

Process_Step:

Process_Description:: Measured within-subplot latitude and longitude were converted to a global (plot-scale) XY coordinate system. Latitude and longitude values were converted from slope distance to horizontal distance using the cosine of the slope angle, then added to subplot level offsets.
Process_Date: 2017

Process_Step:

Process_Description:: Stem maps were generated using the R statistical package to display tree locations and canopy openings. Canopy openings were determined using a canopy opening detection algorithm in R based on point-patterns and a user-designated threshold distance from nearest trees. See Scheider and Larson (2017) for more details.

Schneider, Eryn E.; Larson, Andrew J. 2017. Spatial aspects of structural complexity in Sitka spruce-western hemlock forests, including evaluation of a new canopy gap delineation method. Canadian Journal of Forest Research 47(8): 1033-1044. https://doi.org/10.1139/cjfr-2017-0029
Process_Date: 2017

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:: Below you will find a description of the files available in this data publication. If applicable, data minimums and maximums are also provided as: (min, max).

DATA FILES

\Data\Data.csv: Comma-delimited ASCII file containing information on trees in each plot and subplot combination, used by LaBau (1967) and Schneider and Larson (2017). Variables described below.

Plot = plot number. Plots include 32, 76, 104, 111, 130, 132, 141, 143, 161, 220

Subplot = subplot number within Plot. (1, 35)

TransectDirection = direction of transect within Subplot. Directions include 1 (along azimuth of Plot orientation) and 0 (back-azimuth of Plot orientation)

TreeNumber = ordinal tree number within Plot. Trees NOT tagged. (1-945)

Species = 4 letter tree species code. Codes include ALRU (Alnus rubra), CHNO (Chamaecyparis nootkatensis), PISI (Picea sitchensis), POTR (Populus tremuloides), TSHE (Tsuga heterophylla). (There is one case of species=#N/A and the reasoning for this is unknown.)

DBH.in = diameter at breast height (DBH; 4.5 feet, 1.37 meters) in tenths of inches. (30, 699)

DBH.cm = DBH (4.5 feet, 1.37 meters) in centimeters. (7.6, 177.5)

Height.16ftlogs = number of merchantable 16 foot logs from the 2 foot sump to a top diameter inside bark equal to 40% of DBH, but not less than 8 inches in hardwoods or 6 inches in softwoods. Trees under 11.0 inches DBH will receive a 0. (0, 8)

SideSlope.deg = slope from the tree to the closes point of the transect centerline, in degrees. (0, 60)

CenterSlope.deg = slope of the transect centerline, in degrees. (0, 88)

LongCoords.ft = slope distance (in tenths of feet) from the tree to the transect centerline. Positive values indicate tree is to the right of the centerline, negative values indicate tree is to the left of the centerline. (-699, 970)

LatCoords.ft = slope distance (in tenths of feet) of tree along the transect centerline. (1, 864)

Xcoord.m = tree distance from origin along minor axis (i.e., perpendicular to Plot orientation), in meters. Origin is the bottom left corner of Subplot 29. (-11.2, 120.1)

Ycoord.m = tree distance from origin along major axis (i.e., with Plot orientation), in meters. Origin is the bottom left corner of Subplot 29. (0, 140.8)

\Data\Plot_locations.csv: Comma-delimited ASCII file containing information on geographic plot location and stand attributes. Variables described below.

Plot = Plot number. Plots include 32, 76, 104, 111, 130, 132, 141, 143, 161, 220.

Latitude = latitude North in decimal degrees. (56.693, 58.54)

Longitude = longitude West in decimal degrees. (132.854, 134.958)

Elevation.m = elevation above mean sea level in meters. (10, 500)

USGS.1.250000.map = United States Geological Survey aerial photo name

Stocking = Plot volume stocking level, per Moessner (1949). Levels include medium (40-69% canopy cover) and full/well (70-100% canopy cover) stocked.

Gross.vol.Scribner.bdft = total Scribner board foot volume in Plot. (26764, 110947)

SUPPLEMENTAL FILES

\Supplements\Manual_of_field_instructions.pdf: Portable document format file containing information on the process of plot location and data acquisition in 1964, cited in LaBau 1967.

\Supplements\Overview_maps.pdf: Portable document format file containing overview maps of plots in the Juneau and Petersburg, Alaska areas.

\Supplements\Aerial_photo_maps\Plot##.pdf: Portable document format files containing plot maps, named by plot number (##). Maps are scanned aerial photographs and include hand-drawn plot boundaries and relocation information. (## = 32, 76, 104, 111, 130, 132, 141, 143, 161, and 220)

\Supplements\Stem_maps\Plot##.png: Portable Network Graphics files containing plot stem maps, named by plot number (##). Maps were generated in statistical package R and showcase stem locations in XY space, species, size class, gap type, and patch size (Schneider and Larson 2017). (## = 32, 76, 104, 111, 130, 132, 141, 143, 161, and 220)
Entity_and_Attribute_Detail_Citation:: LaBau, Vernon J. 1967. An analysis of design and technique of cluster point sampling in coastal Alaska old-growth forests. M.S. Thesis, Oregon State University, Corvallis, OR. 84 p. https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/g158bn918

Schneider, Eryn E.; Larson, Andrew J. 2017. Spatial aspects of structural complexity in Sitka spruce-western hemlock forests, including evaluation of a new canopy gap delineation method. Canadian Journal of Forest Research 47(8): 1033-1044. https://doi.org/10.1139/cjfr-2017-0029

Distribution_Information:

Metadata_Reference_Information:

Metadata_Date: 20220721

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Justin Crotteau
Contact_Organization: USDA Forest Service, Rocky Mountain Research Station

Contact_Position: Research Forester

Contact_Address:

Address_Type: mailing and physical
Address: 800 E Beckwith Ave.
City: Missoula
State_or_Province: MT
Postal_Code: 59801
Country: USA

Contact_Voice_Telephone: 406-542-4169

Contact_Electronic_Mail_Address: justin.crotteau@usda.gov

Metadata_Standard_Name: FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001.1-1999