Conifer trees near a frozen lake in Northern MN.

MN Impact: University of Minnesota Research on the Affect of Timber Harvest Provides Valuable Information for Forest Managers

November 27, 2019

Objective

Studies conducted to simulate potential changes in natural disturbance regimes on timber harvest goals will provide forest managers with information they can use to develop strategies for future harvesting. 

Issue

The amount of biomass stored in forest ecosystems results from past natural disturbances, forest management activities and current structure and composition. Although natural disturbances are projected to increase in their frequency and severity on a global scale, forest management and timber harvesting decisions continue to be made by individual forest owners.

What has been done

Matt Russell and his team conducted a study to simulate natural disturbance regimes and their interaction with timber harvest goals across the Superior National Forest (SNF) in northeastern MN. Forest biomass stocks and stock changes were simulated for 120 years under three natural disturbance and four timber harvest scenarios. They estimated forest biomass availability across the SNF under all combinations of scenarios.

Results

Simulations with current harvest rates and twice the level of current disturbances resulted in reductions of 2.62-to-10.38 percent of forest biomass across the four primary forest types in the SNF. Under this scenario, total biomass stocks remained consistent after 50 years at current and 50 percent disturbance rates, but biomass continued to decrease under a 200 percent-disturbance scenario through 120 years. In comparison, scenarios that assumed both harvest and disturbance were twice that of normal levels resulted in reductions ranging from 14.18-to-29.85 percent of forest biomass in the SNF.

These results suggest that forest managers should consider both natural disturbances and timber harvesting when trying to determine future forest structure and composition. The implications from simulations like these can provide managers with strategic approaches to determine the economic and ecological outcomes associated with timber harvesting and disturbances.