Stronghold's Demonstration Forest

On Sugarloaf Mountain

Creation of the Demonstration Forest

The Forestry Demonstration area at Stronghold is intended to provide visitors with a visual representation of common forest harvest practices, as well as displaying a long-term comparative view of forest development resulting from these activities.

The demonstration forest began in 1991. The Forest Demonstration Area was developed by identifying five compartments, twenty acres in size, which were harvested using five of the most common Regeneration Harvests. A listing of these practices includes:

  1. Clear-cut,
  2. Seed Tree,
  3. Shelterwood,
  4. Group Selection,
  5. Single Tree Selection.

Each stand has been further divided into five-acre compartments that underwent prescribed harvests in five-year intervals. Harvests occurred in compartment A in 1991, compartment B was harvested in 1996, compartment C in 2001, and compartment D was harvested during the summer of 2006. Regeneration harvests are made to promote the germination, establishment, and growth of young trees in a forest. This new growth results from seed lying dormant in the forest duff, remaining small seedling and sapling sized trees, and sprouts that arise from the stumps of trees that were cut. (Regeneration harvests are usually made in forests that have a majority of trees that are “economically” mature, or forests that are in a declining condition due to insects, disease, fire, storm damage etc. This differs from other cuttings that are intended to “thin” a dense stand of trees.)

The development and maintenance of the Forestry Demonstration Area has been a joint venture between the Stronghold Staff, Maryland Forest Service, and Parkton Woodland Services. The Stronghold staff is engaged in the day to day maintenance of the area, the development of signage, the production of an interpretive brochure, and assisting with the measurement of regeneration. The Forest Service assisted with the layout of the site, the marking of trees for forest harvests, the development of the brochure, and the measuring of regeneration. Parkton Woodland Services is responsible for the implementation and supervision of the commercial timber sales.

Even VS Uneven Aged Management

The stands in the demonstration forest have been arranged to show two broad forest management schemes, namely even aged forests (1, 2, and 3) and uneven aged forests (4, 5). Even aged management refers to a harvest which removes most of the canopy in one or two consecutive harvests. This results in a stand of trees which are nearly the same age. Uneven aged management refers to a series of harvests which never completely remove the canopy from the forest. This method creates a forest with numerous age classes.

Even Aged Management Sign

Even Aged Management

Even aged management refers to forest harvests that remove most of the canopy in one or a rapid series of harvests to develop a forest where all of the trees are roughly the same age. This type of management favors those “shade intolerant” trees that require plenty of sunlight to grow and develop. Trees that tend to do well in even aged management include tulip poplar, black walnut, red oak, white ash, black cherry, pine, aspen, and red maple. Three of the more common Even Aged cutting methods occurred in the Demonstration Forest:

Stand 1: Clear-cuts,

Stand 2: Seed Tree,

Stand 3: Shelterwood.

Compartment 1A is a clear cut harvest that occurred in 1991.

(Photo taken in 2007)

Clear-cuts remove all of the overstory in one cutting, harvesting all trees down to two inches diameter. Trees that regenerated on this site following the harvest include red maple, tulip poplar, ailanthus, flowering dogwood, white ash, black cherry, beech, and oak. We counted an average of 2,300 trees per acre throughout Stand 1A; the average size of the trees was 40’ tall. This harvest in 1A was conducted in 1991.

Compartment 2C is Seed Tree Harvest that occurred in 2001.

In the demonstration forest, 20% of the original canopy was retained in the Seed Tree Harvest area (Stand 2). Most of the trees that were retained as “seed trees” were large tulip poplar and white ash that had far ranging, wind dispersed seed. Trees that regenerated on this site include tulip poplar, red maple, white ash, ailanthus, chestnut oak, dogwood, black cherry, hickory, and black gum. An average of 1,400 trees per acre regenerated in Stand 2C. Most of these six year old trees are 10 -15 feet tall.

Compartment 3B is a Shelterwood Harvest that occurred in 1996.

In the demonstration forest, 40% of the original canopy was retained during the Shelterwood harvest. Many of large trees left behind were oak trees that regenerate from acorns. The shelterwood is one of the more common regeneration methods for promoting oak regeneration. This shelterwood area was impacted heavily by gypsy moth in 2000, and much of the oak canopy had to be removed during the 2001 harvests due to significant mortality. There is an average of 2,100 trees per acre in Stand 3B; the most common species to regenerate were red maple, chestnut oak, white oak, black cherry, ash, red oak, hickory, black gum, and serviceberry. Most of the regeneration is 15 – 20 feet tall.

Uneven aged management areas at Sugarloaf

Uneven Aged Management

Uneven aged management never completely removes the canopy so that a mixture of age classes develops on the site. In the demonstration forest, the Group Selection (Stand 4) and Single Tree Selection (Stand 5) method of uneven aged management was implemented.

The area in the foreground was harvested in 2006 while the trees in the background were harvested in 1991. Some of the original canopy exists as well.

Stand 4 was a Group Selection harvest in which 100’ x 100’ “groups” of trees were removed. This kind of cutting carried out in five year intervals over 20 acres will result in a mixture of age classes, and thus, an uneven aged forest. Some of the original canopy remains in each stand, adding to the diversity of age classes. The most common trees to regenerate in the group selection area were chestnut oak, red maple, black oak, black gum, tulip poplar, beech, and hickory. An average of 1,700 trees per acre regenerated in the Group Selection areas.

Single Tree selection area harvested in 1996.

The Single Tree Selection removed trees based on the diameter of the tree. A predetermined range of diameters was harvested by adopting a Q – factor quotient. For example, if the maximum size tree in the forest has a 26” diameter and the Q – factor was 1.5, then 24” diameter and below would be retained. For a Q-factor of 3.0, 22” diameter and below would be left; a 4.5 Q-factor would retain 20” diameter and below. It often takes a number of years to develop a perfectly regulated forest using this type of harvesting system. The most common trees to regenerate in the single tree selection forest were white oak, red maple, chestnut oak, black gum, beech, and serviceberry. An average of 1,700 trees per acre regenerated in the single tree selection forest.

Over the years, observations taken in the demonstration forest including the type and amount of regeneration observed have been recorded. Permanent survey plots were established in 1994 to eliminate any bias from these observations. Subtle and more dramatic changes occurred in this forest throughout the 15 year period. Some of the more notable observations made over this time period include: The heavy cutting in the even aged management areas yielded more “shade intolerant” regeneration like tulip poplar, ailanthus, black cherry, Virginia pine, along with red maple, ash, hickory, and oak. The less intensive cutting in the uneven aged management area favored regeneration like chestnut oak, red maple, beech, black gum, hickory, and white oak. The amount of seedlings arising from all of the compartments was fairly consistent, averaging about 2,000 young trees per acre. Deer feeding pressure began impacting the young trees about 1994, and subsided in 2000 when a controlled hunting program was instituted on the property. Severe gypsy moth defoliation occurred in this area in 2000; the insects caused pronounced mortality in many of the oak trees that were left in the Seed Tree and Shelterwood areas. (Many of these trees were salvaged as part of the 2001 harvest.)

Numerous other activities and studies have been conducted in this area over the years. The forest was used for a paired watershed study in 1996, monitoring sediments coming off of logged areas compared to an undisturbed watershed. Another study intended to develop and monitor best management practices was conducted on the demonstration forest in 1996. As part of this study, the access and trail system were improved to facilitate foot travel through this area. The Stronghold Staff have also been very good at developing and erecting interpretive signs that identify the many compartments. This forest was also used for the study area for a Master’s degree thesis identifying changes in herbaceous ground vegetation following the harvests.

Stronghold Inc., a Trust set up by the Philanthropist Gordon Strong in 1959 occupies much of Sugarloaf Mountain in southern Frederick County. It is a place where the general public can come for a developing and continuing appreciation of nature.

In 2017 the Board hosted the FFA Forestry Career Development Event at Stronghold.