Study Site Characteristics

If your point is located near a forest/nonforest edge, then be sure to only use the forested portion of your study site when describing the following habitat characteristics. For example, if your point is on the edge of a woodlot adjoining a corn field, then canopy height only refers to the trees in the woodlot. Don’t average the height of the trees in the woodlot with the height of the corn. Also, see Figure 1 (Delineating Study sites) for a diagram of a point on the edge of a clearing near a road.

   • Hydrology during the breeding season—Note whether any of the following are found on part or all of your study site (within 500 feet or 150 meters of the survey point) during the breeding season:
Stream or flowing water—Flowing water present
Pond or standing water/marsh—Standing water occurring in open areas with no trees
Forested wetland/swamp—Standing water with trees
Riparian forest strip—A linear (narrow) forested area along the edge of a river, stream, or lake
No water—No surface water on the study site

   • Forest cover type—Mark one category that best describes the trees in the forest canopy at your study site:
Coniferous (natural)—Predominately cone-bearing, needle-leaf trees such as pine, spruce, fir, or larch
Coniferous plantation—Cone-bearing, needle-leaf trees planted by humans, usually indicated by even-aged trees in rows
Deciduous—Predominately deciduous trees such as oak, maple, beech, or magnolia. If your study site is predominantly evergreen broadleaf such as live oak, please note in the “Comments” section
Mixed coniferous/deciduous—A mix of mature trees of each type within the study site

   • Slope—Select the one category that best describes the terrain within the study site: Sloped, Level, or Undulating (up and down)

   • Land use—Mark as many as apply to your study site:
Undisturbed—No obvious human-caused disturbance within the past 30 years; forest appears to be in a “natural” state
Light recreation—Occasional use of hiking trails or roads in the area; little disturbance or noise noticeable
Heavy recreation—Frequent use of trails or roads; noise from recreational vehicles or people often heard
Partially cut—Some trees have been removed from the site but enough remain to consider it a forest
Commercial forest—A forest primarily managed for commercial timber products (lumber, pulp, etc.)
Grazed—Evidence of grazing by domestic animals
Recently burned—Obvious evidence that fire occurred (in understory or overstory) within past 10 years
Suburban woodlot—Remnant forest surrounded by human habitations; includes city parks
Other—List or describe type of significant disturbance in “Comments” section

   • Ownership—Determine who owns the study site:
Private—Owned by individuals, corporations, or private organizations such as The Nature Conservancy, National Audubon Society, or a nature center
Private timber company—Owned by a private forest products company
State—Owned by state or provincial government; includes state or provincial parks, state forests, etc.
County or town—Owned by municipal government
Federal—Owned by the United States or Canadian government; includes federally managed lands such as National Forests, National Parks, National Wildlife Refuges, etc. Mark the agency, if listed, or write the agency name on the line beside “Other” or in “Comments” section
Tribal lands—Owned by Native Americans; includes Indian Reservations or tribally owned lands
Other ownership—If ownership is other than those mentioned here, mark “Other” and fill in comment line or describe in “Comments” section

  

Canopy characteristics

For the purpose of BFL, we define “canopy” as all vegetation that is higher than 20 feet (6 meters). The canopy variables pertain to the entire 500-foot-radius (150-meter) circular study site. We suggest that you wander through your entire site before estimating canopy height and percentage cover so that these values are representative of the entire study site and not just reported for your survey point. Percentage Coverage Field Sheet

   • Canopy height—Estimate the height of the majority of mature trees that make up the canopy within the study site. Do not average tall and short trees; instead give a “typical” height of canopy trees. Indicate the units (feet or meters) on the form. Here is one good way to estimate canopy height:
1. Find a tree that represents the typical height of the canopy.
2. Mark your height (or the height of a co-worker, if you are working in a team) on the tree or a nearby shrub.
3. Stand back from the tree and visually estimate how many “humans” high the tree is. Multiply this number times the human height to get an estimate of canopy height.

   • Percentage of canopy cover—Estimate the percentage of sky that is hidden from view by vegetation throughout your entire study site, when you look up. We have included a series of reference figures with the Field Form that may be helpful. Next, separate this value into the percentage of deciduous canopy cover and percentage of coniferous canopy cover. These two numbers should add up to the number for overall percentage of cover. For example, you might estimate the total canopy cover to be 80% by using the reference figures. Next you would determine that your study site is three-quarters deciduous trees and one-quarter coniferous trees. In this case, you would record 60% deciduous and 20% coniferous canopy cover on your Field Form.

  

• Most common trees in canopy—Record up to three of the most common canopy trees within the study site. Use a field guide to trees or consult a checklist of trees found in your area. If none of the trees listed are appropriate, mark “Other” and write the name(s) on the line or in the “Comments” section. If only one or two species dominate the canopy, only mark or write in those. If you know a more specific name for your canopy trees (such as White Oak for “Oak,” or Pinus ponderosa for “Pine”) please list the names in the “Comments” section.

  

Low vegetation characteristics

For the purpose of BFL, we define low vegetation as all vegetation below 20 feet (6 meters). This includes branches of trees that are lower than this height as well.

   • Percentage of low vegetation cover—Estimate the percentage of the ground that would be covered by living or dead vegetation if you could look down at your entire study site from just below the canopy (rocks, pavement, water, bare soil, etc. should not be included in your total number). We have included a series of figures with the Field Form that may be helpful. Next, separate this value into the percentage of saplings (small trees), percentage of deciduous shrubs, percentage of coniferous shrubs, percentage of ground cover (all non-woody plants such as grasses, ferns, flowers, mosses, etc.), and the percentage of dead vegetation (fallen trees, stumps, snags, leaf litter, etc.). These numbers should add up to the overall percentage of cover. This number must be less than or equal to 100.

   • Most common low-vegetation plants—List up to three of the most common low-vegetation plants within the study site. These may be small regenerating trees of the same species that occupy the canopy or they may be shrubs that remain beneath the forest canopy. Use a plant field guide or consult a checklist of plants found in your area.