Air & Water

Thunderhead at edge of Hurricane Rita

Threats from both air and water are numerous and substantial. Severe weather often poses an immediate and uncontrollable impact on forests. Between 1900 and 2005, an average of 1.6 hurricanes per year made landfall between Texas and Maine, with an average of 0.6 major hurricanes (category 3 or above on the Saffer-Simpson scale) annually. In 2004 and 2005 alone, seven major hurricanes had an impact on the United States (Blake and others 2006).

Although weather severity (e.g., wind speed and duration, or form and amount of precipitation) is clearly an important factor in the occurrence and severity of forest damage, site conditions, tree characteristics, and stand characteristics play a major role in determining resistance of a forest stand to wind, ice, and snow loading. This section explores various aspects of forest vulnerability from severe weather.  It also details the economic impacts of hurricanes on forest landowners. 

Some information on air pollution effects are available in the section Assessing the Threat that Anthropogenic Calcium Depletion Poses to Forest Health and Productivity. Additional sections in the future are hoped to expand on this as well as the topics of climate change and flooding.