MYRLIN Harvesting model

The MYRLIN harvesting model is contained in the module MYRLIN#3. It comprises a simple stand projection model that simulates growth and harvesting on coupes of equal areas. The harvested quantities are displayed by year and by coupe. Rules for harvesting such as felling cycle, diameter limit, and the percentage of commercial stems to be conserved during felling, can be specified. Felling damage factors can be varied. The growth models used are those copied from the MYRLIN#2 module. The initial stand table for each forest stratum is taken from MYRLIN#1.

The outputs produced by the model include:

• the detailed areas and volumes felled from each stratum in each year;
• a summary table of volumes felled by years, with equivalent AAC (annual allowable cut);
• a graph that shows harvests and standing volume by years over time.

The objective of the model is to provide projections of sustainable harvesting that is possible, subject to:

• Species occurrence and distribution, indicated by the stand tables;
• Growth and mortality rate information;
• Logging damage levels;
• Harvesting prescriptions and rules, including diameter limit and felling cycle;

The detailed outputs from the model, by coupe, sub-coupe and year, can form the basis of a management plan schedule. Together with the indicated harvest volumes, these physical quantities can be monitored in a straightforward and inexpensive way to ensure compliance with the plan. The sustained yield volumes also provide a sound basis for investment and financial planning.