Control and management of invasive alien woody plants in the tropics 
  Goodland, T.C.R., Healey, J.R. & Binggeli, P. University of Wales, Bangor, UK September 1998. - School of Agricultural and Forest Sciences Publication Number 14 
  This document is an output from a research project partly funded by the United Kingdom Department for International Development (DFID) for the benefit of developing countries. The views expressed are not necessarily those of DFID.  R6290 Forestry Research Programme.  The work was co-funded by the Darwin Initiative of the United Kingdom Department of Environment, Transport and the Regions.
  Control and management of invasive alien woody plants in the tropics - Summary
  This report draws together recent research and practice on combatting the growing problem caused by alien trees and shrubs. It has most applicability to the tropics and sub-tropics, and concentrates on "environmental" weeds in protected areas, rather than those affecting agriculture or intensive forestry. The main points from the report can be summarised thus:


  Ecology. An understanding of the biology of the alien and the ecology of the invasion process should be fundamental. Ecological data can be costly to obtain, so an assessment has to be made of what level of information is necessary for the most appropriate management response.


  Management. Managers of natural areas should recognise that generally a key requirement is to maintain ecosystems in as close to their 'original state' as possible, but that perhaps all ecosystems apparently undisturbed by human activities can be vulnerable to invasion. Managers should be cautious about introducing exotic plants into protected areas and should try to ensure that potentially invasive plants are detected as early as possible.


  Assessing effects. Many invasive species affect, to a varying degree, the structure and function of invaded ecosystems. However it is difficult to determine accurately their impacts. Furthermore, even if demonstrated, these impacts cannot easily be classified as neutral, positive or negative because the cultural, political, social and employment background of the observer will to a large extent determine the conclusions reached.


  Control. The initial step in developing an effective management programme should be the mapping of the current and potential range of the species, its density and size class distribution. Biological control is at present impractical for tackling many invasions in the tropics, but there is a wide variety of physical/chemical methods for control available, and the labour-intensive nature of this work should be less of a deterrent than in rich countries. Removing dense infestations of woody plants can take over 30 man-days per hectare. 


  1. Introduction
  2. Addressing the underlying causes of invasions
  3. The detection and extent of the species
  4. Assessing the effects of alien woody plants
  5. Managing populations of invasive woody plants
  6. Manual methods of killing woody plants
  7. Biological control
  8. Conclusions
  9. References