Sustaining Timber Harvesting and Older Forest Conditions: A Harvest Scheduling Analysis for Koochiching County's 2010 Forest Plan

Abstract

Analyses were developed to help support the forest planning effort of the Koochiching County Land Department. Emphasis was on comparing scenarios describing plausible management strategies for five forest cover types: (1) aspen, (2) Balm of Gilead, (3) lowland spruce, (4) spruce-fir, and (5) tamarack. These cover types were not analyzed independently, as it was assumed that the annual harvest area, across cover types, is limited by the county's forestry budget. A harvest-scheduling model was applied using a 100-year planning horizon and 5-year planning periods. Analyses used the county's most recent forest inventory information, with results providing scheduled management actions for individual stands. Growth projections to estimate yields for alternative rotation lengths utilized information from a recent Minnesota Department of Natural Resources (MNDNR) study that analyzed Minnesota's wood supply potentials. Average stumpage prices received by the county in late 2009 were used in the objective function of the model that estimated the net present value (NPV) from timber returns. Stumpage prices for aspen have been higher in 2010. NPV estimates were updated to examine impacts of these higher prices.

Initially, analyses examined all nine combinations of three alternatives describing general forest regulation policies by three alternative target levels for the area of the aspen cover type to sustain over time as older aspen (age 55 to 74 or age 55+ aspen). An Initial Benchmark run was developed to help understand the opportunity costs of the scenarios. Modeling results were reviewed by the county’s Forest Planning Advisory Group, with that group requesting analysis of ten additional scenarios. Four of these scenarios (Regulation Alternative G scenarios) allowed 40-year rotations in the aspen cover type. Two unconstrained benchmark scenarios were also considered that included no management constraints. The benchmark runs varied only in terms of the minimum rotation age assumed for aspen (40 years or 45 years). Substantial effort was also placed on modeling a scenario developed earlier for the county by an outside consulting firm. Scenarios were also developed that produced more age 55+ aspen when such conditions are less costly to produce (Scenarios E and Gvariable).