Structure Condition Services Stressors
As our climate changes, it is predicted that there will be greater variability in annual temperatures, as well as warmer maximum temperatures in the summer. Higher summer temperatures can lead to drought and heat stress to forests, resulting in declines in tree health and tree mortality1,2,3. Here, we assess the change in maximum annual temperature in Vermont. Tree are adapted to the long-term conditions they have experienced, therefore deviations in maximum temperature from the long-term mean (both above and below) could be problematic to forests. A high score means that the maximum temperature is close to the long-term mean.
Maximum temperatures are increasing and expect to continue to increase. As winter temperatures warm, more insects can survive the cold season and have higher spring populations. Warmer winter temperatures also contribute to less snowfall and/or snowcover. Rising temperatures may lead to mortality of some tree species. Warmer temperatures also increase evaporation and dry soils, contributing to summer drought.
NOAA, Northeast Regional Climate Center at Cornell University (2020)
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 away from long-term mean (scaled 1-5)
|Directionality of scores||
No change from the long-term mean is better.
|Minimum value used in scoring||
Data minimum - 10% of range
|Maximum value used in scoring||
Data maximum + 10% of range
Data of mean maximum annual temperature for Vermont were gathered from NOAA National Centers for Environmental Information1. We set the target for the dataset as the mean maximum temperature from1961-1990 which is used as the baseline normal for climate comparisons by the Intergovernmental Panel on Climate Change (IPCC). The current year is scored for where it falls between the target and the upper scoring bounds (maximum value in the dataset) or the lower scoring bounds (minimum value in the dataset), scaled to be between 1 and 5.
Acid rain harms forests and other ecosystems by damaging leaves and leaching nutrients.
The length of the growing season varies from year to year, but large or persistent changes can be problematic to forests.
Ozone can cause many negative impacts to forests by reducing regeneration, productivity, and species diversity.
Mercury is a toxin that persists in the environment for long periods by cycling back and forth between the air, water, soil and organisms - resulting in long-term, negative effects to forest ecosystems.
Warmer winter minimum temperatures can allow for non-native species to proliferate, while at the same time stressing native forest trees.
Higher maximum summer temperatures can stress forests, reducing productivity and health.
Changes to precipitation can alter the water balance in Vermont’s forests, causing either drought or deluge.
Snow insulates the soil and tree roots from cold temperatures and provides water when it melts.
Climate change will continue to result in more extreme weather events, which can stress forests beyond what they are accustomed.
Lack of sufficient precipitation can cause both immediate and long-term stress to trees.
As native trees are not adapted to defending themselves from non-native, invasive insects and diseases, widespread damage and mortality can result.