Latest Score:

4.6/5

in 2019

score trend is up over time
Weight: 10%

Trees die for a variety of reasons, from wind storms and lightning strikes, to fungal or insect infestations. Every year, trees die. The trunks may persist for decades as snags (standing dead trees), providing habitat for birds and animals, or as logs slowly rotting on the forest floor and gradually returning nutrients to living plants. However, changes to the baseline tree mortality rate may signify that environmental conditions are changing and could pose problems to the lifespan of our trees. However, changes to the baseline tree mortality rate may signify that environmental conditions are changing and could pose problems to the lifespan of our trees. Here, Tree Mortality is computed as the ratio of the annual mortality tree volume relative to the volume of all trees recorded in forested Forest Inventory and Analysis plots1. Trees included have sound boles and a diameter at breast height (DBH) of 5 inches or greater. The current year is scored as the difference from the long-term mean (scaled 1-5).

-- Expert interpretation for Tree Mortality is not available--

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 (scored 1-5)

Target value

Long-term mean

Directionality of scores

No change from the long-term mean is better

Minimum value used in scoring

Data minimum - 10% of the range

Maximum value used in scoring

Data maximum + 10% of the range

Data on annual tree mortality were extracted from the USFS Forest Inventory and Analysis Program EVALIDator1. We computed tree mortality as the ratio of the annual mortality tree volume relative to the volume of all trees ≥5 inch DBH on sampled plots. We relied on FIA's statistical models for computing this value over time. We set the data target as the long-term mean. The current year is scored for where it falls between the target and the upper scoring bounds (maximum value in the dataset plus 10% of the range) or the lower scoring bounds (minimum value in the dataset plus 10% of the range), scaled to be between 1 and 5.

1 USDA Forest Service. 2017. FIA EVALIDator. Version 1.8.0.01. Available at: https://apps.fs.usda.gov/EVALIDator/evalidator.jsp

CONDITION INDICATORS