A small part of Crow’s Nest Preserve is undergoing some changes as part of a demonstration project intended to create conditions similar to those of an old growth forest and encourage the regeneration of oak trees. The project is called “Structural Complexity Enhancement” (SCE) since it takes an even-aged stand of second growth trees—those that grew up after all the local woods were logged more than 100 years ago—and creates conditions with some large and some small individuals of forest canopy trees.
The area, approximately five acres, is undergoing a variety of treatments including prescribed fire and selective logging.
Unlike a traditional timber harvest, Structural Complexity Enhancement removes smaller canopy trees to add growth to the larger trees. Other trees may be killed by girdling and left standing to provide cavities for cavity-nesting species (squirrels, woodpeckers, some raptors). Some trees may also be felled and left in place to add to coarse woody debris on the ground, another characteristic of old growth forest. These fallen trees encourage fungi, salamanders, small mammals as they become hollow and develop cavities.
The creation of gaps in the forest canopy can then create a lighted forest floor, which encourages regeneration of canopy trees and a proliferation of understory shrubs. The recruitment of new trees makes the forest more multi-aged, a characteristic of old growth. Therefore, SCE can be used to accelerate old growth characteristics in a forest and foster the additional types of wildlife that benefit from the structural complexity.
The study site also underwent a prescribed burn in the spring of 2008 to encourage oak regeneration (pictured above, a slowly creeping fire with 6″ flames comsuming the undergrowth—photo courtesy Jim Thompson). Without fire, the oak forest gradually gives way to beech, red maple, and other shade- but not fire- tolerant species.
Deer exclosures will be installed this year to reduce deer browse in some areas. We are also collecting data on species present at the site before and after the treatment. This site is too small to collect data in repeated plots but large enough to serve as a demonstration. A side benefit of the project is the generation of a variety of small and large logs that will be used in various building stewardship projects at Crow’s Nest in the future (flooring, beams, and trim for building restorations) and educational programs (a miniature log cabin that kids at camp can assemble).
This part of the preserve was chosen because it is not part of the preserve frequently used by the public and because it has the right mix of species to make regeneration possible. (Thank you for your cooperation in not disturbing the research site.) We’re excited, and not a little nervous, about the changes that will take place in this section of the forest.
For questions or comments regarding this project please contact Dr. Jim Thorne at Natural Lands Trust: 610-353-5587.