Alan R. Ek

Development and testing of regeneration imputation models for forests in Minnesota

Abstract Tabular imputation models were developed and tested to estimate postharvest forest stand characteristics in Minnesota. The models were based on a sorting of statewide inventory plot data into sets of tables containing estimates of number of trees and basal area per hectare by covertype, species, and diameter class for young postharvest stands. The primary bases for sorting within the sets of tables were stand age following harvest, and site index. The output tables were organized to facilitate their use as young stand input data to existing growth and yield models. Analysis of these tables indicated that basal area increased rapidly for young stands and then began to level off as stand ages approached 20 years; furthermore, the variability within the tables decreased as forest stands matured. Implications for alternative methods of implementing the models are also discussed.

Restoration of the 1936 Statewide Forest Survey of Minnesota

Over 300 stand and stock tables and summary of volume tables for Minnesota were restored from the first FIA Lake States forest survey conducted between 1930 and 1938. The level of detail of the data varied, but included area of forest cover types and stand size classes, and number of trees and volumes per acre by individual species. The data was presented in an Access database with a series of tables and queries. Definitions and further explanations about the restored historic data can be found in Staff Paper Series No. 241, Department of Forest Resources, University of Minnesota