Sulphur oxide injury

Latin name: Veneficium sulfureum Humain
French name: Intoxication à l'oxyde de soufre
Division: Pollutio
Class: Vaporifera
Synonym(s): Pollution (SO₂) ,
Soufre gazeux (SO₂)

Description

Micro-habitat(s)

Leaf, Needle

Distribution

Canada

Damage, symptoms and biology

SO₂ or sulphur dioxide is one of the main atmospheric pollutants. SO₂ is transported over great distances, especially when it is released from the tall smokestacks of industrial facilities that burn fossil fuels. The problem thus reaches well beyond industrial regions, threatening forests located in areas with good air quality. Because it is a gas, SO₂ is transported readily by air currents. It can also penetrate needles and leaves, where it dissolves into the cellular fluids and becomes transformed into an acid, leading to cell destruction. SO₂ also dissolves in the clouds, forming acid precipitation, which damages the upper layers of leaves and needles and penetrates into the organs, causing serious metabolic disturbances. Acid precipitation also leads to acidification of the soil and leaching of the nutrients contained in the soil. Various types of damage result from the combination of these different phenomena. A frequent sign of damage is yellowing and discoloration of needles in conifers and tissue necrosis followed by defoliation in deciduous trees.

Other information

As a rule, conifers are more sensitive to the environmental disturbances caused by sulphur dioxide. Wheat and apple trees are particularly sensitive to this pollution source, but maples appear to have some resistance.