Honeysuckle Friend or Foe

This Progress Report submitted by Ryan Geismar, Josie Leimbach, Kerilyn Fields, Michael Hemme [e-mail:Jochatterbox@hotmail.com] on 11/18/00.

Honeysuckle: an invasive species

We plan to research honeysuckle as an invasive species. There are several aspects we will observe. First, we will determine where in a forest honeysuckle prefers to grow. For example, does it grow on the outer edge or deeper within the forest? Second, we will observe the effects a creek has on the growth of honeysuckle. Does the creek act as a barrier and prevent it from spreading, or does it act as a corridor by allowing light through, thus helping it to grow? We will observe where honeysuckle grows along a creek - on one side or collected at a bend. Finally, does honeysuckle smother native plants? Does it block light from smaller plants and shrubs?
We want to measure how far into the forest honeysuckle grows, if there is a noticeable growth difference in interior samples, the health of honeysuckle growing in the interior, effects of land slope on the growth of honeysuckle, direction of slope, age of tree, and size of tree. We hypothesize that honeysuckle's growth is affected directly by:
Sunlight – Shown by the canopy cover and length of time the leaves spend on the branches
Slope of the land – contributes to the spread of the plant and decreases canopy cover
The creek – acts as another edge and also possibly as a barrier
Height of the plant – allows the honeysuckle to receive light first and steals it from lower plant species
Abundance of the plant – The greater the number of plants, the greater the number of seeds, the greater the possibility of survival. This trend will continue exponentially unless something restricts it.
We hope to find that it does not flourish in the center of the forest, without the presence of a creek, due to insufficient sunlight. We also expect sloped areas to be inhabited by more honeysuckle, even in the forest interior, because of gaps in the canopy allowing sunlight to penetrate. We want to determine the age of honeysuckle in proximity to the creek compared to the specimens on the edge of the forest. This will suggest where the spreading originated. We expect that it grew near the creek and eventually began inhabiting areas exposed to more sunlight, such as the forest's edge.
We decided on this study because it sparked interest and provided many possibilities for discovery. The questions were derived through research of honeysuckle and its invasive characteristics. We also discussed research options with the professor. Honeysuckle originated in Japan and is native to eastern Asia. It was introduced to cultivation in 1862 on Long Island and is now widely naturalized in the eastern and central United States. This project applies to our class focus because it relates to nature and honeysuckle's effects on other plant life.

In the past, the research on Lonicera maackii, more commonly know as honeysuckle, has been based on the effect it has on the native plant life it interacts with, as well as how it is dispersed. In the interaction, it has been found that the honeysuckle often smothers the native species, in order to create more room for its own growth. "Where L. maackii becomes established in the understory of forests, it has a negative impact on tree seedlings and herbs" (Hutchinson). This negative impact is do to the height of the plants found in the area which allows them to steal the sunlight from native plants. While honeysuckle usually has a negative effect on the plant life around it, it positively effects the soil, "The Japanese honeysuckle, a brutal invader of woodlands that can limb up and smother large trees, also protects a steep band from erosion" (Pelczar). When dealing with the dispersal of the seeds in spreading the growth, it has been found that the most prevalently dispersed through birds. However, this method has limitations, "Large expanses of land apparently act as a barrier to the dispersal of this naturalized shrub" (Hutchinson). This is the main basis of our hypothesis; “What does stop honeysuckle?” We are working to show this theory is true in many different environments including our own. Also, forest which have had little disturbances, i.e. tree clearing, etc., are more difficult for the honeysuckle to invade. "L. maackii is absent/rare in old-growth forest stands" (Hutchinson). While it does have its limitations, honeysuckle is very adaptive, "Lonicera maackii seeds are dispersed in a non-dormant condition. The shrub can establish throughout a wide range of environments" (Luken, Goessling). Their adaptability, is a threat to the native species in the area, but this threat is compounded by their speed of growth. "Japanese honeysuckle, Lonicera maackii grow much faster in an environment rich in CO2 than their native counterparts" (Sasek). By learning the growth patterns of the honeysuckle, and their rate of growth, we hope to be able to predict the trends of growth, and therefore perhaps help lead to a solution to limit growth so that the native species have a chance.

Materials and Methods
Our observation of the invasive properties of honeysuckle requires the creation of experimental tests. To run these experiments we will need the following: tape measure, canopy-measuring device, and a saw. The tape measure will be used to measure off the area in which we choose to take our samples from, and also to measure the height and width of the honeysuckle bushes. The canopy-measuring device will do just that. We need it to measure how dense the canopy is in the areas where we are taking the samples. The saw is to cut the trunk so we can count and observe the rings.
For the experiment, we will measure off twenty strips of land, one meter wide by fifty meters long, from the forest edge to the interior. Also, half of the sample strips should be from the creek bank inward. These sample strips of land will be five meters apart. When walking these strips, we need to take note of the slope of the ground (both steepness and direction), the canopy density, the honeysuckle population, and the height and diameter of the honeysuckle. When we come across a honeysuckle bush, along with measuring its size, we need to find out the age of the bush by cutting the trunk and counting its rings. Historical events, drought or wet season, will also be noted through observation of the rings. Observations of other invasive characteristics such as the smothering of ground cover and smaller shrubs or plants will also be noted. These tests/observations will hopefully provide results capable of answering the inquiries we have.
For Tuesday, October 24, we will split the class up in to four groups; each member of our research group will lead one of the class groups. Each group will be responsible for five strips of land one meter wide by twenty-five meters long. Two of the groups will take samples from the creek bed toward the forest interior and the other two will take samples from the forest edge inward. They will make observations on the slope of the land, canopy cover, and honeysuckle population. Also, they will take measurements of the height, width, and age of the individual honeysuckle specimen. The age of the honeysuckle, however, will only be taken every five meters, by sawing the trunk in half and counting the rings.

We expect to find that the honeysuckle will flourish at the banks of the creek and the edge of the forest, since it needs large amounts of light to survive. This is also where we expect to find the larger, healthier specimen. The honeysuckle that we come across in the interior of the forest, if any, will not be as large as its relatives on the edge and will be much more sparse. If there is honeysuckle that flourishes in the interior of the forest, we expect to find a direct correlation with the slope of the ground and the density of the forest canopy. If the ground has a slope, more light will be allowed through the canopy of the forest. We also plan on finding a definite pattern to the age of the honeysuckle that we come across, indicating the direction in which it is spreading.

Time Line
The counts of the abundance in the forest
Collected the samples from the strips (every 5 meters)
Collected the data needed in order to analyze the results
Expand research to encompass hypothesis
Post progress report and data
To do
Find the Trisel dissertation (talk to Gorchov) by November 27
Finish analyzing the data by the 1st of December
Compile data by Monday, November 20th
Complete lab report by December 3rd and revise by the 5th

From the Creek (all measurements of length are in meters)

Strip 1 5 meters in 10 meters in 15 meters in 20 meters in 25 meters in
Height 2.5 2 1 1 2.5
Width .3 .2 .15 .1 .35
Age 7 2 1 6 11
Abundance 8 15 8
Overall Abundance 31
Canopy Cover 70%

Strip 2
Height 3 2.5 2.25 2 3
Width .1 .25 .1 .25 .05
Age 12 11 16 17 10
Abundance 16 22 9
Overall Abundance 47
Canopy Cover 50%

Strip 3
Height 2 2.25 2 2.75 2.25
Width .1 .2 .15 .05 .1
Age 5 13 9 14 6
Abundance 20 19 8
Overall Abundance 47
Canopy Cover 50%

Strip 4
Height 3 2.5 4 2.5 3
Width .25 .1 .3 .1 .3
Age 9 9 29 14 13
Abundance 25 17 6
Overall Abundance 48
Canopy Cover 15%

Strip 5
Height 2.5 2.25 2 2.5 2
Width .25 .15 .1 .2 .05
Age 15 13 11 17 6
Abundance 21 13 3
Overall Abundance 37
Canopy Cover 30%

Strip 6
Height 3 2.5 1.8 2.75 2.5
Width .2 .25 .27 .27 .3
Age 3 3 2 6 4
Abundance 15 22 12
Overall Abundance 49
Canopy Cover 15%

Strip 7
Height 1.4 3 3.25 .91 1.2
Width .19 .25 .13 .23 .25
Age 4 8 7 3 4
Abundance 22 19 15
Overall Abundance 56
Canopy Cover 70%

Strip 8
Height 3.75 1.8 3 4.5 2.25
Width .31 .25 .4 .43 .14
Age 9 6 6 4 6
Abundance 22 18 11
Overall Abundance 51
Canopy Cover 80%

Strip 9
Height 3 4.5 2.5 4.5 2.5
Width .19 .25 .25 .2 .37
Age 8 20 8 12 4
Abundance 15 20 15
Overall Abundance 50
Canopy Cover 50%

Strip 10
Height 2.5 2.25 3 2.75 3
Width .22 .21 .14 .07 .3
Age 6 3 10 8 8
Abundance 20 27 15
Overall Abundance 62
Canopy Cover 40%

From Edge of Forest to Interior

Still compiling data

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