Rybacki Tract-FOR 366

Celine Colbert and Elyse McMahon

4/5/2013

The Rybacki Tract was analyzed using variable radius plots that were determined using stratified random sampling. The tract was divided into two distinct strata using the road passing through the tract as a boundary. The data from each stratum was then analyzed to draw conclusions about the contents of the tract as a whole.

Site Description

The study site was located in Stone Valley, PA. The actual study site starts several meters in from the gate located at the parking lot. The boundary of the eastern line is marked with Penn State signs. The south-western boundary was arbitrarily chosen. The entire length of the study site is approximately 512 meters long and 200 meters wide. The northern boundary is distinguished by Shaver’s Creek. The southern boundary is determined by edge habitat. The total area of the study site is approximately 166 acres. Each stratum is approximately evenly distributed by the road path that can be seen on Figure 1.

Stratum 1

Stratum 1 was located on the northern side of the road, with Shaver’s Creek as its most northern boundary. This area was dominated by Hemlock (Tsuga canadensis), White Oak (Quercus alba), and Chestnut Oak (Quercus Montana). The average diameter in this stratum was 19 inches or 48.26 cm. The density of ft2 per acre was an average of 169.84 ft2/ac.

Stratum 1 had a wetland environment due to its proximity to the creek. The area can be characterized as a lowland range with flat land and limited amount of slope throughout. It had a significant amount of variable sized rocks on the ground either scattered above the ground or partially buried in the ground. This site also had a large amount of moss growing on rocks and on trees. Due to the time of year this study was conducted, there was a limited number of understory species that could be identified. However, some species observed included Mountain laurel (Kalmia latifolia), rhododendron (Rhododendron maximum), black birch (Betula lenta) and cat-briar (Smilax rotundifola), red maple (Acre rubra) and small hickory species (Carya). This stratum also had a great deal of fallen logs that were in different stages of decomposition in this area.

This stratum had significant populations of white tailed deer and rabbit species. Throughout the study days, deer pellets, deer tracks, and rabbit pellets were observed. There was also evidence of bird species, specifically woodpeckers who were using stags and dead trees as sources of food.

Stratum 2

Stratum 2 was located on the southern side of the road, with the edge habitat on the southern boundary of this plot. This area was dominated by White

Oak, Chestnut Oak, and Hemlock respectively. While these are the same species that were in Stratum 1, they are in different order of dominance. The average diameter in this stratum was 17 inches or 43.18 cm. The density of ft2 per acre was an average of 63.33 ft2/ac.

Stratum 2 was also a wetland environment, but was scattered with smaller streams and a wetter soil than Stratum 1. The area was also characterized as a lowland range with flat land, but there were not any slopes. This area had rock outcroppings as well, but not as many as observed in Stratum 1. There was a much larger amount of moss growth on rocks and trees. This may be due to the fact that the area was filled with small streams that were causing overflow to the rest of the area. Understory species that could be observed included hickories, maples, black birch, and cat briar. This stratum also had a significant amount of fallen logs that were probably the same amount as in stratum 1.

This stratum also had evidence of wildlife populations including white tailed deer, rabbit species and woodpeckers. However, these species were not as prominent in this stratum.

Figure 1 Cruise Map for Scotia Tract

Methods

To conduct this project we created a map of the study site with a grid of 2X2 chains. We used variable radius plots that were determined using stratified random sampling.

We sampled a total of 36 plots for the total study area with 13 plots in each stratum. We determined the number of plots by determining the number of plots we would be able to complete in the allotted time and dividing them with respect to the area of each stratum. Because the strata had similar areas, it worked out that the same number of plots were taken on each stratum.

We chose our plot locations based on a 2X2 chain grid, which allows us to sample throughout the area without sampling too close to each plot, yet still obtaining a large pool of plots to randomly select from for sampling.

We measured all tree species that were over 5 inches in diameter. We recorded the merchantable height of those individuals who were greater than 12 inches in diameter. We also recorded the quality of the wood, determining if it was sawtimber, pulpwood, or dead. Since we used a variable radius plot method of sampling, we also measured borderline trees to determine if they were within the plot or not.

Results

Table 1 This table shows how total and live basal area differs between stratum

Stratum

Per BA (total)

90% conf Low

Upper CV SE Per BA (Live)

90% conf Low

Upper SE CV

1 121.43 106.95 135.91

0.25

8.18

110.71 96.40 125.03

8.08

0.27

2 88.00 78.17 97.83 0.23

5.52

74.00 64.92 83.08 5.10

0.25

Combo 104.44 94.05 114.84

0.30

6.09

93.70 83.48 103.93

7.31

0.33

Table 2 This table shows how the number of trees varies between stratum

Stratum

# Trees (live)

90% conf Low

Upper CV SE # Trees (total)

90% conf Low

Upper SE CV

1 106.90 88.36 125.44

0.37

10.47

122.29 104.20 129.14

9.79

0.30

2 90.42 78.68 102.16

0.26

6.59 105.31 91.97 118.65

7.48

0.26

Combo 103.17 90.27 116.07

0.38

7.56 116.67 104.20 129.14

7.31

0.33

Table 3 The table below shows how volume differs between strata

Stratum

Volume 90% conf Low

Upper CV SE Value 90% conf Low

Upper SE CV

1 11822.53

10280.32 13364.74

0.28 870.85 1986.95 1745.32 2228.57

136.44

0.26

2 11206.83

7491.30 14922.36

0.67 2084.70

3379.06 2108.84 4649.28

712.69

0.76

Combo 14131.67

9802.01 18461.32

0.93 2538.47

3092.95 2211.16 3974.73

516.99

0.87

Table 4 The table below shows the average dbh and QMD of the different species in the different strata

Strata 1 Strata 2Species

Average dbh QMD Species Mean QMD

Tsca 8.1 17.7 Qual 17.7 27.9Qual 9.5 21.0 Casp 8.6 23.3Acru 14.5 26.4 Bele 6.3 21.5Bele 10.8 24.6 Tsca 18.9 28.6

Quru 17.2 24.9 Qumo 15.8 27.1Qumo 16.0 27.1 Pist 19.6 29.2Other 14.7 26.1 Other 14.4 26.9

The tables above compare various measurements of the data and their prescision. Table 1 shows that stratum 1 has far more both live and dead basal area than stratum 2. The confidence intervals show that our data gives a relatively precise estimate of the mean. Table 2 shows that stratum 1 does not necessarily have much larger trees than stratum 2 because the number of trees is also far greater in stratum 1. The significant difference between the number of trees and the number of live trees shows that there is a large number of standing dead trees exsist in both strata which was observed in the field. In stratum 1 there were eastern hemlock killed by hemlock woolly adelgid, and numerous white oaks were dead in stratum 2. The volume and value are both greater in stratum 2 which is expected considering that we know there are more trees with more basal area in stratum 2.

Table 4 shows that the average diameters for a species change between strata. This is not too suprising considering that growing conditions are different between strata. For example, the more open canopy and rockier soil of stratum 2 lead to larger average diameter white oakes and eastern hemlocks despite there being less overall trees. Black birch is the one species that grew with a greater average diameter in stratum 1 than stratum 2.

38%

17%

12%

7%

6%

6%

14%

Strata 1 Live Basal Area by SpeciesTsca Qual Quru Litu Qumo Acru Other

Figure 2 Live Basal Area by Species in Stratum 1

47%

8%

10%

7%

7%

3%

17%

Strata 2 Live Basal Area by SpeciesQual Qumo Tsca Quru Acru Pist Other

Figure 3 Live Basal area by Species in Stratum

47%

17%

12%

11%

5%

2%5%

Strata 1 Volume by SpeciesTsca Qual Quru Litu Qumo Pist Other

Figure 4 Volume by Species in Stratum 1

55%

13%

12%

8%

6%4%

2%

Strata 2 Volume by SpeciesQual Tsca Pist Quru Qumo Frpe Other

Figure 5 Volume by Species in Stratum 2

33%

27%

20%

10%

4%

2%4%

Strata 1 Value by SpeciesQual Quru Tsca Qumo Litu Quve Other

Figure 6 Value by Species in Stratum 1

69%

12%

8%

4%3%

2% 1%

Strata 2 Value by SpeciesQual Quru Qumo Tsca Frpe Pist Other

Figure 7 Value by Species in Stratum 2

The basal area charts show that while eastern hemlock makes up the majority of the basal area in stratum one with white oak having the second highest percent at practically half as much, there is a stark difference in stratum 2 where white oak makes up about half of the live basal area and eastern hemlock accounts for less than an eighth of the total. The volume by species also reflects the larger content of eastern hemlock in stratum one and the dominance of white oak in stratum two. Another difference between the two is the significant presence of tulip poplar in stratum 1, with no representation of this species in stratum 2. The value distribution reflects the large margin in price between white oak and hemlock through white oak’s position as the species with the highest percent of total value in both strata. Both strata are also similar in that red oak is responsible for the second highest percent of value in each despite only making up about 10% of the value in each stratum.

The following diameter class distribution charts show that stratum 1 had far more trees per acre than stratum 2. This allows the makeup of stratum 2 to be easily determined as having black birch and hickories making up most of the smaller understory species and white oak monopolizing most of the canopy. Some similarities exist between the two in that both had black birch and hickory contributing to the understory, but stratum 1 additionally had the contribution of red maple which was unseen in stratum 2. Overall, in addition to more trees, stratum 1 had a more varied species composition than stratum 2.

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 28 30 31 350

2

4

6

8

10

12

14

16

18

20

Stratum 1 Diameter Class Distribution by Species

OtherQumoQuruBeleAcruQualTsca

Diameter Class

Num

ber o

f Tre

es/A

cre

Figure 8 Diameter Class Distribution for Stratum 1

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 29 270

0.5

1

1.5

2

2.5

3

3.5Stratum 2 Diameter Class Distribution by Species

OtherPistQumoTscaBeleCaspQual

Diameter Class

Num

ber o

f Tre

es/A

cre

Figure 9 Diameter Class Distribution for Stratum 2