Measuring Forest Community Composition

View of Aurora Sanctuary Forest

Birds play a crucial role in the life cycle of many plants and animals. Birds often are involved in the distribution of plant seeds to distant lands. Anyone who has had bird feces on their car can give evidence that their diet is chiefly composed of seeds. Also necessary in the bird’s lifecycle is a place to live and rest. The Cleveland Audubon Aurora Sanctuary is an ideal area for this and as such is home to thousands of trees in which the birds may roost. This forest is mostly comprised of mature hardwood trees but evidence of prior farming lives on in the form of mature pines which were planted by farmers as wind breaks.

Trees come in lots of shapes and sizes

When looking at a forest from a scientist perspective, it is important to assess the plant community composition. This is helpful in understanding how diverse or even a forest is and also how species rich it is. Data can be compiled through many methods such as the Point Centered Quarter (PCQ) Method. It involves compiling tree data (diameter and species) of certain trees that fall into a particular point along a quartered transect. This method is relatively fast and easy to conduct due to the fact that not all trees are measured in the plot. Also, since only certain trees are measured, randomization can be accounted for. Large trees, which were specified by having a diameter greater than 20 centimeters at breast height (dbh = diameter at breast height) and small trees, less than 20 cm dbh yet bigger than 2.0 cm dbh, were located and measured. It is important to measure both large and small trees in a forest in order to be able to determine how plant community composition changes over time.

Measuring distance from the point to the tree

The tools needs for the PCQ Method are a specific type of measuring tape called a DBH tape. This tape is dual sided, while one side is used to measure distance in meters, the reverse side measures circumference and converts the diameter in centimeters. The distance taken between quarters was  determined using a random numbers table. The random numbers table gave a number of paces taken in between each quarter. Once the appropriate amount of paces were taken, a plot was divided into four transects.

The DBH tape converts circumference into diameter in cm.

From this point, the closest small and large trees in each of the four transects were measured. Both the distance from the origin of the quarter to the tree, as well as the diameter of the tree was recorded. After measuring the closest small and large tree in each quarter, the species was identified and recorded. Most species were able to be identified by their leaves using field guides. Some species were identified with a dichotomous key in the lab afterwards.

All data is carefully recorded

Red Maple: leaves have finely serrated leaf edges
In the fall, they turn bright red

Sugar Maple: leaves have 5-points with coarse serration
In the fall, they turn yellow

PawPaw Leaf

Tuliptree Leaf

Hawthorn Leaf

For more information on the species found, click on their name below:

Acer rubrum (Red Maple)

Acer saccharum (Sugar Maple)

Asimina triloba (PawPaw)

Carya ovata (Shagbark Hickory)

Carya cordiformis (Bitternut Hickory)

Crataegus sp. (Hawthorn)
Fagus grandifolia (American Beech)
Fraxinus americana (White Ash)

Lindera benzoin (Northern Spicebush)

Liriodendron tulipifera (Tuliptree)

Pinus strobus (White Pine)

Prunus serotina (Black Cherry)
Quercus alba (White Oak)
Quercus rubra (Red Oak)

Ulmus americana (American Elm)

For More Information on the Aurora Sanctuary:

Cleveland Audubon Aurora Sanctuary
  - Be careful hiking in this area after it has rained, the wooden bridges and stairs can be slippery -
  - Also be aware that a permit is needed for work / hiking off of the trail-


 
By: Lindsay, Jay, and Maria