Saint-Lambert is underlain by Ordovician period black shale.
This bedrock is covered by deep clay drift over most of the town.
Soils were poorly drained in their natural state; as such, they were classified as gleysols—strongly acidic (Longueuil series) under most of the town and neutral to mildly alkaline (Boucherville series) in part of the western section (Préville).
 Drainage and excavation have been used to adapt the soil for housing construction.

The most common trees in Saint-Lambert are those species which tolerate poor drainage.
These include poplars, willows, red maple, silver maple and green ash.
The American elm was formerly abundant but its population has been severely reduced by Dutch elm disease.
Non-native species are commonly represented by Norway maple, silver birch, English oak, blue spruce, common horsechestnut and honey locust.
Rare exotics which benefit from St-Lambert's favorable microclimate include Japanese maple and tulip tree.
Most trees in Saint-Lambert show some evidence of damage from an ice storm in January 1998 and a severe thunderstorm in June 2008.
Saint-Lambert is underlain by Ordovician period black shale. This bedrock is covered by deep clay drift over most of the town. Soils were poorly drained in their natural state; as such, they were classified as gleysols—strongly acidic (Longueuil series) under most of the town and neutral to mildly alkaline (Boucherville series) in part of the western section (Préville).  Drainage and excavation have been used to adapt the soil for housing construction.
The most common trees in Saint-Lambert are those species which tolerate poor drainage. These include poplars, willows, red maple, silver maple and green ash. The American elm was formerly abundant but its population has been severely reduced by Dutch elm disease. Non-native species are commonly represented by Norway maple, silver birch, English oak, blue spruce, common horsechestnut and honey locust. Rare exotics which benefit from St-Lambert's favorable microclimate include Japanese maple and tulip tree. Most trees in Saint-Lambert show some evidence of damage from an ice storm in January 1998 and a severe thunderstorm in June 2008.
Saint-Lambert, Quebec