1. AIR POLLUTION
AND FOREST HEALTH
ESRM 101
Spring 2007
Bob Edmonds
264 Bloedel

2. EPA MAJOR AIR POLLUTANTS
Carbon monoxide
Nitrogen dioxide
Ozone
Lead
Sulfur dioxide
Particulate Matter – <2.5 um; um

3. AIR POLLUTION PROBLEMS IN FORESTS
1. Gaseous air pollutants
Sulfur dioxide
Ozone
2. Acid Rain and Fog – pH, NOx, SO2
Particulate pollution – haze
Most are human-caused, but some are natural (e.g., volcanoes produce SO2)

4. Attempts to Control Air Pollution
Clean Air Acts – 1955, 1970, 1990, 1997

5. GASEOUS POLLUTANTS
SULFUR DIOXIDE – Stationary sources
Power generation - coal burning
Smelters
OZONE – Mobile sources (automobiles)

6. SULFUR DIOXIDE DAMAGE

9. Sulfur dioxide injury

11. OZONE DAMAGE

12. Ozone forms from photochemical action of sunlight on
automobile (internal combustion engine) exhaust
in the presence of hydrocarbons
sunshine and hydrocarbons
NOx from exhaust Ozone (O3)

18. Green – good; yellow – moderate, red – unhealthy for sensitive groups

19. Smog in southern California forests -
mostly ozone produced by photochemical
oxidation of NOx in auto exhausts

20. Ozone damage to ponderosa pine in southern CA

21. Ozone damage to ponderosa pine in California

22. Ozone
damage -
flecking

23. Are Washington’s
Forests at Risk
From Ozone?
A healthy
old-growth
forest
ecosystem in
Mt. Rainier
National Park

25. A healthy young Douglas-fir forest?

27. ACID RAIN AND FOG
pH < 5.3

28. A German Norway spruce forest monitored for forest
health. Unhealthy trees have flat tops largely attributed to air pollution and acid rain. Air pollution influences forests worldwide.

29. European Forest Decline
Waldsterben
Mostly attributed to acid
rain.
1987
1988
1993

30. Emissions from power plants

35. Clingman’s Dome, NC
tree mortality
Adirondak stream - stream
acidification, fish kill
Acid rain damage to forests and
streams in the eastern U.S.
Most of tree mortality due to
the Balsam woolly adelgid

36. Dead trees at Clingman’s
dome, Great Smoky Mountains
National Park (left)and Mt.
Mitchell, NC (below).
Initially attributed to acid rain,
but mostly due to the Balsam
woolly adelgid
Definitely unhealthy

37. Particulates -
Clean air is a problem in cities and in National Parks
(reduced visibility in the Grand Canyon, Mt. Rainier, etc
affects tourists

38. Particulates

39. Real time visibility cameras
Mt. Rainier NP
Sequoia-Kings Canyon NP

40. HYPOTHESES FOR FOREST DECLINE
Acidic inputs (rain, snow, fog)
Ozone
Combination of pollutants
Excess Nitrogen – a new concern
Climate change
Pathogens and insects