Ecological and economic determinants of invasive tree species on Alabama forest lands

Abstract.  This research assessed the impact of ecological and economic factors on the incidence and number of invasive trees on Alabama forest land.  This study was motivated by limitations of earlier studies that generally focused on individual species at a small scale, and ignored the role of economic activities in the spread of invasive trees.   Based on statistical analysis of the 2004 Alabama Forest Inventory Analysis (FIA) data, results showed that the incidence of invasive species on a plot depended on site productivity, growing stock, site slope-aspect orientation, eco-region, forest management type, and whether a plot was located in a metropolitan county.  The number of trees of invasive species per plot was influenced by the same set of factors, as well as type of ownership, and management activity.  Thus, both ecological and economic factors need to be considered in countering the menace of invasive species invasion.

Background/Question/Methods Invasive plant species have adverse ecological and economic impacts.  The rationale of this study is that ecological and socio-economic factors determine the location of high priority sites related to invasive species.  Specific objectives of the study are to examine the spread patterns of these invasive tree species from 1990 to 2004 on Alabama forestland, and furthermore, to evaluate ecological and economic factors associated with the occurrence and abundance of invasive trees on Alabama forestland.  We propose that by identifying the underlying factors associated with the spread of invasive tree species, forest managers will be able to identify high priority areas on a regional scale.  This study also contributes to the field of invasive species modeling by evaluating analytical techniques that are suitable for occurrence and abundance of invasive tree species.

Results/Conclusions To reduce potential damages associated with invasive tree species, various management strategies have been considered in recent years.   To supplement these strategies, this research developed an analysis protocol identifying several ecological and economic factors that influenced the occurrence and abundance of invasive trees on Alabama forests.  In designing plans to prevent and control the spread of invasive species, it will be important to differentiate between factors influencing occurrence and abundance, and to augment ecological factors with economic drivers.  In this regard, the following insights from this research might prove helpful.