Structure Condition Services Stressors
Vermont's forests provide important habitat for certain species of birds that need interior forest patches for breeding, food, and cover from predators. Further, trees rely on birds for flower pollination, seed dispersal, and pest control1. Examining annual bird counts of forest-dwelling bird species can provide an indication of the quality of the forest habitat in supporting wildlife. Here, forest bird species abundance is assessed using a Living Planet Index (LP1)2. The current year is scored as the difference between the maximum and minimum (scaled 1-5).
The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.
Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.
Distance between maximum and minimum (scaled 1-5)
Data maximum + 10% of range
|Directionality of scores||
Higher values in the data are better.
|Minimum value used in scoring||
Data minimum - 10% of range
|Maximum value used in scoring||
Data maximum + 10% of range
Data on forest bird counts by species were collected by Vermont Center for Ecostudies1 at forested locations throughout Vermont beginning in 1989. From these data, we computed a Living Planet Index (LPI) 2. We used a beta package for R, rlpi3, to compute the LPI for all species and birds. We used equal weighting among species and no sub-groupings. Only those Forest Bird Monitoring sites with a complete record were included: Cornwall Swamp, Dorset Bat Cave, Moose Bog, Roy Mt WMA, Shaw Mt, Sugar Hollow, The Cape, and Underhill State Park. The Living Planet Index ranges from zero to one. We computed the index and set the target to 1, and the current year is scored as the difference between the target and the current year value, scaled to be between 1 and 5.
Timber harvested from Vermont's forests provide jobs and income to the state, and support the maintenance of forest land.
Aquatic species that live in forested streams provide an assessment of the health of the surrounding forest.
The ability of forests to support big game species for hunting is an important service on which many Vermonters rely.
The amount of carbon stored by forests helps offset rising atmospheric carbon dioxide concentrations.
Maple syrup production is an iconic staple of Vermont's landscape and is reliant on the continued health of maple trees.
The number of people using Vermont's forests for camping and hiking provides a measure of the value of our forests for recreational uses.
The number and diversity of bird species that live and use forested habitats provides a sense of the quality of Vermont's forestlands for a variety of species.