Maximizing tree harvesting benefit from forests under insect infestation disturbances

Area of Science:

• Ecology
• Mathematical Biology
• Forestry

Background:

• Forest population dynamics are significantly impacted by coupled disturbances (stressors).
• Current modeling often focuses on individual stressors or uses descriptive statistics for interactions, highlighting a gap in mechanistic approaches to disturbance synergy.
• There is a need for integrated modeling that addresses multiple disturbances and incorporates their processes.

Purpose of the Study:

• To develop and analyze an age-structured forest-beetle mechanistic model incorporating tree harvesting.
• To investigate the impact of different beetle equilibrium states (none, endemic, epidemic) on forest dynamics.
• To apply optimal control theory to evaluate various benefit functions related to forest health and harvesting.

Main Methods:

• Developed an age-structured mechanistic model for forest-beetle interactions and tree harvesting.
• Investigated three scenarios based on beetle equilibrium states: absence, endemic, and epidemic.
• Utilized optimal control theory to analyze three distinct benefit functions considering healthy and dead trees.

Main Results:

• Numerical simulations indicate that maintaining endemic beetle populations is sufficient for preserving a forest with trees of all ages.
• Harvesting benefits generally decrease as beetle infestation levels rise.
• An exception to decreased harvesting benefits occurs when the benefit function includes costs and uniform wood value across tree conditions.

Conclusions:

• Managing beetle infestations at endemic levels can be a viable strategy for maintaining forest age diversity.
• The economic benefits of harvesting are sensitive to beetle population dynamics and the specific cost-benefit considerations.
• Mechanistic modeling provides valuable insights into the complex interactions between forest ecosystems, pests, and human activities like harvesting.