Evaluating the Performance of a Forest Succession Model to Predict the Long-Term Dynamics of Tree Species in Mixed Boreal Forests Using Historical Data in Northern Ontario, Canada

Guy R Larocque,F Wayne Bell

doi:10.3390/f12091181

Abstract

Environmental concerns and economic pressures on forest ecosystems have led to the development of sustainable forest management practices. As a consequence, forest managers must evaluate the long-term effects of their management decisions on potential forest successional pathways. As changes in forest ecosystems occur very slowly, simulation models are logical and efficient tools to predict the patterns of forest growth and succession. However, as models are an imperfect representation of reality, it is desirable to evaluate them with historical long-term forest data. Using remeasured tree and stand data from three data sets from two ecoregions in northern Ontario, the succession gap model ZELIG-CFS was evaluated for mixed boreal forests composed of black spruce (Picea mariana [Mill.] B.S.P.), balsam fir (Abies balsamea [L.] Mill.), jack pine (Pinus banksiana L.), white spruce (Picea glauca [Moench] Voss), trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), northern white cedar (Thuja occidentalis L.), American larch (Larix laricina [Du Roi] K. Koch), and balsam poplar (Populus balsamefera L.). The comparison of observed and predicted basal areas and stand densities indicated that ZELIG-CFS predicted the dynamics of most species consistently for periods varying between 5 and 57 simulation years. The patterns of forest succession observed in this study support gap phase dynamics at the plot scale and shade-tolerance complementarity hypotheses at the regional scale.

Highlights

Emulating natural disturbances in managed forests has been recommended as a means to sustainably manage boreal forests for timber production, climate regulation and climate change mitigation [1], biodiversity [2], and many other ecosystem services that are essential to human well-being [3,4,5]
The factors that must be considered in the comparison of the predictions of gap models with observed stand data can be classified in three groups [29]: (1) degree to which the environmental site variables used in the simulations are accurate and representative of the field conditions; (2) extent to which observed data, which may originate from inventory surveys, represent the forests under examination; and (3) extent to which potential successional changes and management activities are taken into account
The historical long-term sample plot data set used in this study originated from a databank developed and maintained by the NDMNRF Growth and Yield Program and the measurements were conducted by ministry staff or forest companies mentioned above, which provides a strong confidence in the validity of the measurements

Summary

Introduction

Emulating natural disturbances in managed forests has been recommended as a means to sustainably manage boreal forests for timber production, climate regulation and climate change mitigation [1], biodiversity [2], and many other ecosystem services that are essential to human well-being [3,4,5]. These multiple social and environmental demands have led to increasing pressure on forest ecosystems. In boreal forests, evidence points to gap dynamics at the local scale and species succession at the landscape scale

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