Old Forest Research

Cutleaf toothwort

Cutleaf toothwort

We already know there are 350+ species of plants in the Old Forest. What we don’t always know is where all those species are, how they’re relating to each other, and whether those relationships are different now than they were 10, 20, or 50 years ago.

But the greater concern is what the forest will look like several decades from now. That’s why Overton Park Conservancy is committed to ongoing research in the Old Forest. Luckily, we have a wealth of partners in Memphis to help us out. Here’s a small sample of some of the research that’s been conducted in the woods.

Taylor Sieben conducts a down woody debris survey to create a GPS map of large fallen trees.

Taylor Sieben conducts a down woody debris survey to create a GPS map of large fallen trees.

Rhodes College Midtown Urban Forestry Fellowship (ongoing)
Under the supervision of Dr. Kimberly Kasper at Rhodes and Eric Bridges at Overton Park Conservancy, students from Rhodes College visit plots in the Old Forest several times per week to collect data about:

  • GPS locations, height, diameter, and growth rates of the large old “remnant” trees
  • Locations of canopy gaps left when large trees fall, and regeneration rates of new trees there
  • Species, locations, and extent of harmful invasive plants
  • Amounts of each plant species
  • Evidence of insects and disease in plants

This information can then be analyzed alongside previous studies of the Old Forest’s plant composition to determine things like why today’s oak saplings are not reaching maturity, even though there are many large, older oaks in the canopy.

Seedling Dynamics (ongoing)
Because healthy regeneration is so important to retaining the Old Forest’s character, Dr. Tara Massad of Rhodes College is also studying this issue. She began a seedling dynamics study in 2015, installing seed traps throughout the forest. She and her students periodically collect seeds, document the species mix, and germinate them in City of Memphis greenhouses. She will then compare the regeneration success of the greenhouse seedlings with those growing in the forest near the seed traps. If the seeds germinate more successfully in a greenhouse, that could mean the forest seeds aren’t getting enough sunlight to germinate, that there’s too much leaf litter for the seedlings to push up, or that insects are over-consuming the foliage of the plants that do germinate. That might also mean that the greenhouses can offer at least temporary assistance in establishing the next generation of trees.

Herbarium Collection (ongoing)
Dr. Rachel Jabaily of Rhodes College and her students periodically collect voucher specimens of plants in the Old Forest, adding them to the Rhodes herbarium in a special collection for Overton Park research. These specimens establish a baseline from which we can monitor change, and they’re also a valuable source of genetic information. Specimens can only be collected from the Old Forest with the permission of the Tennessee Department of Environment and Conservation, which approved this project because of its long-term value to understanding the health of the forest.

 

hootieCopperhead Research (ongoing)
Under the advisement of U of M professor Dr. Judith Cole and Memphis Zoo Curator Dr. Steve Reichling, researcher Malle Carrasco-Harris is conducting a multi-year study comparing the highly-isolated population of copperheads in Overton Park with those in other local forests. Her goal is to understand the effect of urbanization on snake populations. She collects snakes, brings them to the Memphis Zoo to be microchipped, returns them to the same location, and then tracks their movements via radio equipment. This allows her to analyze the same snakes over time, to see if their weight and length have changed, if they’re reproducing, and if they’re making significant moves across the forest. Read more here.

Ecological Assessment (1987)
Dr. James M. Guldin conducted an assessment as part of the 1987 Overton Park master planning process. He noted that many of the large canopy gaps (created when large trees fall and sunlight is let into an area for the first time in many years) did not appear to be regenerating with the oak and poplar trees that give the Old Forest so much of its character. Despite the existence of many large-diameter oaks and poplars, and the presence of a number of 3-5-year-old saplings, the mid-level trees were missing.

When Dr. Guldin returned recently, he had hoped to see that those saplings had grown into viable trees, but instead he found that many of the gaps were in the same condition as they were in the 1980s. Something was holding those trees back from making it to the mid-story, and ultimately to the canopy. It will take future research projects to determine what that cause might be, as well as the solution. Rhodes College fellows have been replicating the study to see what has changed in the past 30 years. Read Dr. Guldin’s study here.

Floristic Survey (2009)
Over the course of a year, Dr. Thomas Heineke conducted a thorough inventory of all plant life found within the Old Forest. He observed 332 flowering plant species from 85 plant families, a number he describes as “amazing” given the forest’s relatively compact size and lack of topographic variation.

You can see the complete list and download a copy of the study here. Want to see it come to life? Check out our interactive field guide to the plants of the Old Forest on iNaturalist.