INVASIVENESS OF CONIFERS: EXTENT AND POSSIBLE MECHANISMS

Data on natural regeneration and spread of introduced conifers are summarized.
Invasiveness of conifers is associated with small seed mass (<30 mg) and very often with short juvenile period (<15 years) and short intervals between large seed crops (<5 years). Examples of invasive species are Cryptomeria japonica, Larix decidua, Picea sitchensis, Pinus contorta, P. strobus, and Pseudotsuga menziesii. Many rare and endangered conifer species exhibit opposite characters, particularly large seed mass and long juvenile period (e.g., Araucaria spp, Pinus maximartinezii, Torreya spp.). These results are consistent with predictions which we made earlier using a discriminant function derived from data on attributes of invasive and non-invasive pines.
Regeneration or invasions of conifers with seed mass <5 mg (e.g., Chamaecyparis spp., Pinus banksiana, Tsuga spp.) are mostly limited to wet and preferably mineral substrates.
Vertebrate dispersal is responsible for the spread of some coniferous species with otherwise non-invasive characters (e.g., Pinus pinea, Taxus baccata).

IV International Conifer Conference

M. Rejmánek, D.M. Richardson

biological invasions, dispersal, endangered species, regeneration, spread

https://doi.org/10.17660/ActaHortic.2003.615.40