Skaneateles Conservation Area/Invasive species/Acer platanoides

<< Regulated and other highly invasive plants at the SCA

Acer platanoides (Norway maple)
Norway maple (Acer platanoides) was brought to North America from England by in 1756. It was planted widely as a hardy shade tree, but it has escaped into northeastern forests and has become a severe ecological threat.

Invasiveness ranking for Acer platanoides (Norway maple)
Norway maple was ranked as Very Highly Invasive, with a relative maximum score of 82% in its 2008 New York State assessment.

Norway maple is now regulated by New York State law, which means that "…no person shall knowingly introduce into a free-living state or introduce by a means that one knew or should have known would lead to the introduction into a free-living state any regulated invasive species, although such species shall be legal to possess, sell, buy, propagate and transport."

1. Ecological impact (37/40)
1.1. Significant alteration of ecosystem processes (7/10):


 * Norway maple trees cast heavier shade than native tree species, decreasing light availability.


 * Planted to reduce erosion in areas that are prone to erosion.


 * Casts an extremely dense shade, has a shallow root system, and suppresses lawn grasses underneath it. The same qualities suppress both the diversity and the total amount of undergrowth in a naturalized setting.

1.2. Major alteration of natural community structure (10/10):


 * Increases the density in the existing (tree) layer.


 * Tolerates poor soils and extreme temperatures and thus leads to the creation of a new (tree) layer where one might not have developed (or at least not as fast) were succession left to native species


 * Suppresses the understory and reduces or eliminates the shrub and herb layers, and saplings of native tree species.

1.3. Major alteration in community composition (10/10)


 * Reduces species richness and biodiversity


 * Suppresses growth of saplings of native tree species


 * Suppresses or eliminates native shrub and herb species.


 * May facilitate growth of non-native plants.

1.4. Severe impact on other species or species groups (10/10)


 * Norway maple is a preferential host for Asian long-horned beetle (Anoplophora glabripennis), and other pest insect species.


 * Large stands of Norway maple support high populations of these insect pests, which then can lead to infestations on less preferred native tree species.


 * Fang (2020)
 * Alters forest canopy structure
 * Changes herbivory rate for seedlings
 * Changes N dynamics in the soil
 * More shade-tolerant than red maple seedlings
 * Facilitates further invasion of Norway maple in forests (positive feedback)
 * Serious tree invader in North America

2. Biological characteristics and dispersal ability (21/25)
Munger (2003)
 * Insect pollinated.
 * Seeds are wind-dispersed and the dispersal distance from seed source is enhanced by winged samaras.
 * Samaras dry substantially before dispersal and seeds are desiccation-tolerant thereafter.
 * Seeds are dispersed in fall, which provides a high likelihood of protection under winter snow.
 * Seeds germinate in spring following an obligatory period of cold stratification at 3-4 °C for 90-120 days.
 * Germination is apparently enhanced by soil disturbance.

2.1. Abundant reproduction (4/4)


 * Copious production of viable seeds.

2.2. Moderate opportunities for long-distance dispersal (2/4)


 * Seeds mainly fall within a short distance from parent trees (less than 100 meters), but there is potential for long distance dispersal (100+ m.) by wind or water.