This module allows students to explore how different types of forest extraction
and management (i.e. selective logging and harvesting of a non-timber forest
product) may affect the sustainability of the forest and associated tree genetic
resources. The three case studies in this module are based on information from
published studies and cover a number of issues related to the overall question ‘Is
sustainable harvesting of forest resources possible and how are the viability and
genetic resources of harvested species affected?’ The issues addressed include:

• Inbreeding – changes in mating patterns after logging
• Population bottlenecks and genetic drift
• Modelling – evaluation of long-term impacts of extraction
• Dysgenic selection – high grading, logging of the best trees
• Reproductive materials – source of regeneration

Downloadable materials
Module 4 - introductory notes for teachers  [ PDF  [1] (1.1 MB)]
Case Study 4.1 Impacts of selective logging on the genetic diversity of two Amazonian timber species Case Study 4.2 Does selective logging degrade the genetic quality of succeeding generations through dysgenic selection?  [2] Case Study 4.3 Conserving Prunus africana: spatial analysis of genetic diversity for non-timber forest product management   [3]