Latest Score:

4.9/5

in 2019

score trend is flat over time
Weight: 10%

An invasive pest is an insect or disease that has been introduced from another country and causes extensive damage where it is introduced. Examples include emerald ash borer and Dutch elm disease, among many others. Most of our most problematic invasive pests originate from Europe and Asia because those locations have many tree species that are closely related to those found in Vermont. When an invasive pest is introduced to an area, native trees can succumb to serious damage because they have not evolved to develop chemical and physical defenses against them. To quantify the damage caused by invasive insects and diseases, we use Insect and Disease Surveys (IDS), which are annual aerial surveys of forests conducted by the State of Vermont and the USDA Forest Service to map forest disturbance, including damage caused by insects and diseases1. Here, we summed the total area mapped by pests that we could determine as invasive to Vermont. The current year is scored as the difference between the minimum and maximum (+10%) values in the record. Annual scores were computed as the deviation from the data target, scaled from 1-5.

1 USDA Forest Service. Forest Health Protection. https://www.fs.fed.us/foresthealth/applied-sciences/mapping-reporting/gis-spatial-analysis/detection-surveys.shtml

Invasive pests pose a unique problem to native forests by attacking species that have few defenses against them. Historically, these have caused the decline of some species in the region (e.g., American chestnut, American elm). We see this occurring at present with emerald ash borer (EAB) in many states throughout the country. The data presented here are from aerial detection surveys (ADS) conducted by the Vermont Division of Forestry and the USDA Forest Service, and it is expected that as EAB continues to be detected in the state, the acres of forest affected by the insect will increase in the coming years. Here, we summed the total area mapped by pests that we could determine as invasive to Vermont. The current year is scored as the difference between the minimum and maximum (+10%) values in the record. Annual scores were computed as the deviation from the data target, scaled from 1-5.

Interpretation provided by:

Josh Halman, Forest Health Specialist; Vermont Department of Forests, Parks and Recreation (2020)

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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.

Component Description
Scored as

Distance between target and maximum (scaled 1-5)

Target value

Lower

Directionality of scores

Lower 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

To quantify the damage caused by invasive insects and diseases, we use Insect and Disease Surveys (IDS), which are annual aerial surveys of forests conducted by the State of Vermont and the USDA Forest Service to map forest disturbance1. Here, we summed the total area mapped by pests that we could determine as invasive to Vermont. The target was set as the lowest possible acreage, and the current year is scored for where it falls between the target and the upper scoring bounds (maximum value in the dataset + 10% of the range), scaled to be between 1 and 5.

1 USDA Forest Service. Forest Health Protection. Available at: https://www.fs.fed.us/foresthealth/applied-sciences/mapping-reporting/detection-surveys.shtml

STRESSORS INDICATORS