FEMC: Tracking Shifts in Disturbance Regimes

Change Type:
Drought

Drought is a driver of forest disturbance that impacts varios ecosystem processes across populations. As temperatures are anticipated to increase and preciptiation is anticipated to decrease across the region, the impacts of drought may become more severe in the Northeast. Drought is an extreme climate metric that quantifies the cumulative lack of percipitation in a given area and can be used as a predictor of forest disturbances. Based on 20 years of data from the US Drought Monitor we extracted data for the region in the four drought categories found in the region: D0 - Abnormally Dry, D1 - Moderate Drought, D2 - Severe Drought and D3 - Extreme Drought.

Analysis

STATE:
Drought frequency is represented as the number of weeks of drought recorded in each USDM drought category
Drought severity is assessed as the number of weeks severe or extreme drought conditions were recorded
Drought extent is represented by the percent of total area (acres) with recorded drought by USDM drought category
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Disturbance Trend Summary

The data indicate that while the number of weeks in moderate to extreme drought is relatively stable over the study period, the number of weeks with abnormally dry conditions has increase slightly.

The same pattern exists for the percent of the region experiencing drought in any given year, with stable trends for moderate to severe drought but slight increases in the percent of the region experiencing abnormally dry conditions.

Highlights

  • 2002 was abnormally dry, with drought conditions reported somewhere in the region for every week of the year, and extreme drought reported for 39 weeks.
  • 2016 was also particularly dry, with drought conditions reported across almost 60% of the region. It is notable as being one of the primary causes of the extensive Lymantria dispar outbreaks in southern New England (see Pests and Pathogens - Established Invasives)
  • Trend data indicates that drought conditions are becoming more common and widespread but the high year to year variability prevents any of these trends from being statistically significant.

Additional Resources

Data Program Years Org Data Products