Air Pollution and Forest Decline Waldsterben

1
Air Pollution Effects on plants
Important to read section on Forest decline in
Goudie
Air Pollution and Forest Decline (Waldsterben)
2
Air Pollution Effects on plants

• Can occur in gaseous or particulate form
• Primary (SO2, NOx, CO) versus secondary (O3,
  photochemical products) forms important
  distinction. Also particulate versus soluble
  distinction.
• Can be toxic to plants (SO2)

3
Plant grown in similar soil along a gradient of
sulphate intensity in Leeds sowed lower yield at
high concentrations
Criticisms of experiment
4
One third of England and Wales has lost most of
its epiphytic lichen flora because of sulfur
pollution.
Several experiments have examined the effect of
air pollution on lichens in major European cities
with similar results replication
Factors other than sulphate may be involved
flouride, photochemical smog, etc.
5
Industrial smog from Sudbury, Canada, pump out 2
million tonnes of gases annually, selects out all
but the hardiest of trees (White pine) from a
large area of land. This is true of many areas
of the world with large smelters.
6
Photochemical smog has had an impact on
vegetation within cities and in the outskirts.
Smog in L.A. has damage Ponderosa pines as far
as 129 km from the city.Ozone (70 pphm in LA)
can reduce photosynthesis, inhibit flowering and
germination. It can also predispose plants to
infections.Particulates can clog stomata,
reducing the absorption of CO2.
7
Forest Decline

• An environmental problem that came to prominence
  in 1980s.
• Symptoms
• 1. Growth decrease
• (slower growth, increase susceptibility to
  pathogens,
• premature aging of needles)
• 2. Abnormal growth
• 3. Water Stress

8
Surveys in Europe show that there has been
substantial damage in many of the forest of Europe
The problem has been particularly prevalent in
Poland, Czech Republic, and a major concern in
many other European countries. It has been a
concern in high elevation Eastern coniferous
forests in the US
9
Hypotheses concerning forest decline

• Poor forest management
• Aging of forests
• Climate change/severe climate
• Nutrient deficiency
• Viruses/pathogens/pests
• Pollution gases, soil acidification (including
  the increase in aluminium, and other ions in
  soil), nitrogen saturation, trace gases,
  pesticides etc.

10
Multiple simultaneously applied stresses may be
the cause.
Nihlgard, proposes the accompanying scheme that
shows a chronological sequence of stress
Although this has retreat from public attention
in recent years the problem has not disappeared -
there are still debates over the appropriate ways
to assess the problem, and about the cause of the
problem, and about the public policy implications
of forest decline