Maximum Density Study

Aim: To document the highest density possible which occurs when height increment accumulates and mortality begins, or more simply, to determine what is full stocking for loblolly pine.

Maximum Density plots 1-5, 31 & 32: These plots are located on the north end of the main campus at the University of Arkansas at Monticello on the road leading to the rodeo barn. Where the rode turns to the right, plots 1-5, 31, and 32 (which are contiguous and oriented in the cardinal directions in two perpendicular rows, starting with plot 1 at the south through plot 5 at the north and with plots 31 and 32 contiguous to plot 3 and perpendicular to the west, plot 32 being the outermost or most western plot.) are located at 131.7 meters past the gate to a pin on the north side of a witness tree (loblolly pine, 45 feet in height, 23 inch dbh, marked with two blue flags). The bearing and distance from plots 1-5, 31 and 32 witness tree to the south east corner of plots 1-5, 31 and 32 is S72W and 9.8 meters. The south east corner of plots 1-5, 31 and 32 is aligned to S87W and to N3W.

Maximum Density plots 6 and 61: Plot 6 is located past the same gate at 68.5 meters to a witness tree (shortleaf pine, 70 feet in height, 16 inch dbh, marked with blue tape). The bearing and distance from plots 6 and 61 witness tree to the south east corner of plot 6 is S76W and 5.7 meters. The south east corner plot 6 is aligned to S90W and to N0W.  Plot 61's southern edge is 1/2 meter north and 9/10 of meter east of plot 6's northern edge and on a parallel alignment. 

In addition, long poles were placed at the north and south ends of plots 1-5 and at the south end of plot 6 to aid relocation. Pins of ½" thick, 1 ½’ long rebar were driven into the outer corners of plots 1, 5, 32, 6 and 61 with approximately 4" protruding. The latitude and longitude of the southeast corners of the Maximum Density plots are given below.

South East Corner of Plots 1-5 & Plots 31-32              error = 24 feet

                                                                                    elevation = 287 feet

                                                                                    Lat 33 degree 35' 47.8" N

                                                                                    Long 091 degree 49' 4.5" W

South East Corner of Plot 6 & 61                                 error = 22 feet

                                                                                    elevation = 272 feet

                                                                                    Lat 33 degree 35' 45.7" N

                                                                                    Long 091 degree 49' 4.6" W

Normal Density plots 7 and 8: Two normal density plots were established just to the north of the high density plots. Plots 7 and 8 are located past the same gate 240 meters to the north along the road. At that point, one follows a trail to the left or west (a large rotting log is by the trail entrance) for approximately 100 meters. The plots are approximately 10 meters to the left of this trail. Blue marking tape hanging from a tree marks the spot. The two plots are aligned in a north/south row. Plot 7 is the southern most plot. Pins of ½" thick, 1 ½' long rebar (4" protruding) are driven into the outer corners of the two plots. The latitude and longitude of the southeast corner of Plot 7 is given below.

South East Corner of Plot 7 & 8                                     error = 23 feet

                                                                                      elevation = 287 feet

                                                                                      Lat 33 degree 35' 52.9" N

                                                                                      Long 091 degree 49' 7.5" W

A plot diagram is available at this link.

The Maximum Density study site: The study site consist of 5 meter by 5 meter square plots with (plots 1-5) aligned in a north/south column with a buffer zone around the edges. Two plots (plots 31-32) are contiguous and perpendicular to the west of plot 3, with plot 31 being the eastern or inner plot. Plots 6 and 61 were established approximately 60 meters directly south of the contiguous seven plots. The Maximum Density sites are overwhelmingly loblolly pine with a few hardwoods, approximately 10 years old in 2006, and seeded in by large roadside trees.  It is interesting to note that plot 6, while having a nearby shortleaf pine seed tree, consists entirely of loblolly pine.  Also, all high density sites lay in a low, moist strip which is adjacent to the road and line of seed trees, and, as a result, resulted in high levels of seeding and germination.  The sites were picked for their high density.

The Normal Density study site: This study site consists of two, 8 X 8 meter square plots aligned in a north/south row with a buffer zone around the edges. The sites are dominated by pine with hardwoods growing in underneath, and are the result of planting at 8 X 8 foot spacing. The sites were picked for their optimal density and are approximately the same age as the Maximum Density sites.

Plots 1-6, 7, 8, 31, and 32 were established in February 2006 at a stand age of 10 years.  Plot 61 was established in January 2007 at a stand age of 11 years.

Bearings were taken with a hand held compass in degrees. Diameter at breast height was taken with calipers in centimeters. Total heights and heights to live crown were taken with a vertex hypsometer in feet and tenths. Crown widths were measured with a logger’s tape in feet and tenths. Plot layout measurements and other measurements were taken with a distance tape in meters. Species was determined by pine (10) or hardwood (11). Tree vitality was determined by alive (1) or dead (0). GPS readings were taken with a model Garmin GPSmap 60CS. Inventories involving all trees were done marking off each plot into strips to aid in measurement. In addition, in the re-count of the especially high density plot 1, meter wide rows and columns were subdivided by a measuring tape to facilitate an accurate count and these 1 meter squares were further subdivided into decimeters to facilitate mapping of every individual stem in plot 1. All plots, Normal density and Maxdensity received measurement of all trees diameter, species (pine or hardwood), and vitality (alive or dead). In addition, select small, medium, and large trees in plots 1-5 received measurements of total height, height to live crown, and of crown width in two perpendicular directions. Cores were taken of trees immediately outside the plots to determine stand age.

Findings

At the 14th Biennial Southern Silviculture Research Conference held during February 2007 in Athens, Georgia a paper titled "The Densest Loblollly Pine Stand and Its Silvicultural Implications" was presented.  Findings on plot density and implications in the calculation of stand density index were discussed.

Data Files

All files with the *.dat extension contain unformatted (ASCII) data for the site.  Each *.dat file is accompanied by an explanatory file with the *.doc extension.

MaximumDensity.dat, MaximumDensity.doc - Contains plot number, diameter at breast height in centimeters, tree vitality (alive/dead), and species (pine/hardwood).

NormalDensity.dat, NormalDensity.doc - Contains plot number, diameter at breast height in centimeters, tree vitality (alive/dead), and species (pine/hardwood).

SelectCrowns.dat, SelectCrowns.doc - Contains diameter at breast height in centimeters, crown width in feet and tenths in two perpendicular directions, total tree height and height to live crown for selected small, medium, and large trees in plots 1-5 (MaxDensity).

Plot1Map.dat, Plot1Map.doc - Contains one by five meter row number (1 being the southernmost row and 5 the most northern), the five by one meter column number (1 being the westernmost column and 5 the easternmost), the one decimeter X coordinate within an individual row and column one meter square, the one decimeter Y coordinate within an individual row and column one meter square, diameter at breast height in centimeters, tree vitality (1 = alive, 2 = dead), species (10 = pine, 11 = hardwood).  A Plot1Map diagram is available at this link.

F

   Fig. 1. Diameter at breast height is measured with calipers by     Fig. 2. Dense growth characterizes the Maximum Density plots.

   Dr. Boris Zeide.

  Fig. 3.  Border area is also characterized by dense growth.        Fig. 4. Trees in Plot 1 were mapped to the nearest decimeter

                                                                                                  using one meter sticks.

   Fig. 5.  The canopy of the maximum density plots.                     Fig. 6. Seed trees which seeded in the maximum density plots to

                                                                                                   the left.

  Fig. 7.  Normal Density plots are much                  Fig. 8. A row of trees from the Normal Density original planting         

  more open and have larger trees,                           is evident in the center of the above photograph.

  larger trees, but are approximately the

  same age as Maximum Density plots.

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