Escaping arboreta: understanding the ecological impacts of a non-native tree recently escaping cultivation

Abstract

Many plant communities are threatened by invasive tree species as they may alter understory diversity through changing forest structure and forest floor conditions. Invasive species typically follow an invasion timeline of a lag phase where a species has recently established and population size is low, followed by a proliferation phase where population size exponentially grows and may begin to impact the ecosystem. This study was designed to describe the invasion timeline and spread of Tetradium daniellii (Beebee Tree), a species which recently escaped from cultivation across the Mid-Atlantic region. I also investigated if T. daniellii invasion was associated with altered understory and canopy-level forest characteristics. Results indicate site-dependent lag phase lengths and understory responses. Invasion was associated with lower leaf litter, but relationships with other variables differed between sites. Management plans should focus on early detection in the 20–50 year lag phase and consider the dominant species already present in invaded area.