FOREST ECOLOGY LAB 1: ENVIRONMENTAL GRADIENTS
Group Members Liza, Dave, DJbrilla
Abstract
Our experiment focuses on a set of linear plots along a 100 yard slope at Heiberg
Forest in Tully, NY, looking at whether there is stable regeneration of tree species
throughout. We used ten sample plots along this transect, gathering data from each
regarding the number and species of young trees that are growing. By comparing our
results to those of the group studying mature tree species, we will be able to conclude
whether tree regeneration is stable or not.
Introduction
Because our transect is located along a slope, there is the possibility that there
may be environmental differences within that in some way affect regeneration. Examples
of such factors could include differing soil types or textures, and drainage class.
Although we do not yet know if such differences are present, we can later correlate our
findings with other groups who are investigating such conditions.
Despite the likelihood of at least some varying environmental factors over the
slope, we feel they are unlikely to be of sufficient magnitude to have a significant effect
on regeneration success. Therefore, we expect NOT to see a distinct gradient in
regeneration. Alternatively, one tree species might be more affected by certain conditions
than others, so there is the possibility that individual species might exhibit regeneration
trends. Depending on the severity of change in controlling environmental conditions,
there is a final, third possibility that most or all of the tree species in the transect will
display some sort of gradient in their reproduction efforts.
Methods
Materials:
 Loggers Tape
 Flagging
 Tree Key

Procedure:
 Plot centers were marked out for us.
 Using the Diameter Tape, measure and mark plot boundaries with a 15’ radius.
 With one person recording, other two group members canvass plot area, giving
species and designation to trees under two inches DBH.
 Loggers tapes are used to determine class.
 Following completion of a plot, individual counts are tallied by species.
Results
Species
Striped
Plot
1
10
Plot
2
Plot
3
Plot
4
Plot
5
2
Plot
6
Plot
7
Plot
8
Plot
9
Plot
10
Maple
Sugar
Maple
Service
Berry
American
Beech
Red
Maple
Norway
Spruce
Hemlock
1
1
2
2
2
20
30
1
20
3
2
7
9
4
5
6
4
5
5
8
36
27
Unidentified
7
12
1
12
4
4
Please see excel document, Chart 4 for graph.
Discussion
The results from our findings showed that tree species did vary as placement on
the gradient slope varied. Certain species of trees are shown to thrive more in higher
elevation while other species are shown to thrive in a lower elevation along the gradient
slope. The Striped Maple and American Birch are example of tree species that thrive at
higher elevation while species such as Hemlock thrive at the lower elevation.
Environmental factors related to elevation, such as drainage, are likely to be responsible
for such variation.
In order to complete our lab, we must compare our understory regeneration data
to lab group 4’s overstory data. As we have previously stated, we expected that the
regeneration of tree species along this gradient slope would follow the same ratio of
mature trees along the slope. Upon looking at group 4’s data, which is conveniently
posted on the FOR 332 website, we can make these observations and test our hypothesis.
Just as our stem count for each species varies along the gradient slope, so does group 4’s
stem count. In areas such as Plot 1, our regeneration data clearly matches that of the
mature tree species; there is an abundance of maples in both of our groups. Also, in Plot
7, both groups have shown to have a significant amount of Hemlocks. While group 4 has
shown there are 5 mature Hemlocks in plot 7, our group has shown that there are 7
hemlocks regenerating in the same plot.
Though there some plots’ data shows that our hypothesis is true, not all plots are
regenerating the mature species that are present. For instance, we did not find a
regenerating Black Cherry stem in any of our plots, even though group 4 found many
occurrences of mature Black Cherry stems. Also, the area of most abundant mature
Hemlock stems was in plot 9, where there is absolutely no Hemlock regeneration. The
area of most abundant Hemlock regeneration is instead in plot 5.
Conclusion
Our hypothesis that tree regeneration along this 100m gradient slope at Heiberg Forest in
Tully, NY, is stable has been proven partially true. We predicted that tree species would
vary along the gradient slope due to environmental factors involved, and this was proven
true. In some cases, the variation of regenerating trees along this slope matched the
variation of mature trees along the slope. Such a match proves our hypothesis true.
However, there are some plots where there is an abundance of mature tree species and a
lack of regenerating tree species, and vice versa. This unstable regeneration could be
caused by a number of factors that we did not account for, such as crown size, fern
growth/density, and lack of sunlight reaching the forest floor.