Modeling paludification and fire impacts on the forest productivity of a managed landscape using valuable indicators: the example of the Clay Belt

Sylvie Gauthier,Osvaldo Valeria,Frédéric Raulier,Alexis Schab,Jesus Pascual,Yves Bergeron

doi:10.1139/cjfr-2020-0386

Abstract

In areas sensitive to forest management, paludification and successive disturbances in boreal forest can affect forest regeneration negatively, sometimes resulting in stand opening. As these negative effects on forest productivity are not fully considered in strategic management planning, a new landscape dynamics model integrating fire, paludification, forest harvesting, and regeneration failure was used to assess these impacts in a large forest management unit (10 828 km2) of northwestern Québec. Two reforestation scenarios, one based on the accessibility of the areas to be treated and the other aimed at restoring all burned and paludified areas to production were compared with one with no intervention. The success of the scenarios was evaluated using the predicted volume harvested, the proportion of closed or opened stands areas, which is an indicator of productivity, and the cost of reforestation and the royalties associated with harvesting. Harvesting the paludified areas without reforesting would lead to a sharp increase in open stands areas (+17.3%). The strategy of reforesting accessible areas is the most promising for achieving sustainable forest management targets. The monitoring of maximum potential volume and the closed forest area as indicators of landscape productivity provides the ability to anticipate problems earlier than with the conventional forest planning indicators.

Highlights

In Canada, the boreal forest provides many ecological benefits, including a large carbon stock (Lemprière et al 2013), and is an important source of wood fiber (Brandt et al 2013)
To foresee the productivity problems induced by regeneration failure, we developed the maximum potential volume (MPV) as a valuable indicator
Effects of paludification and fire on forest management unit (FMU)’s productivity Compared with the business as usual (BAU) scenario, the effect of fire on the success rate of the harvest schedule plan is marginal over the entire planning horizon, whereas the effect of paludification is slightly more pronounced with a median of 0.98 compared with the BAU scenario

Summary

Introduction

In Canada, the boreal forest provides many ecological benefits, including a large carbon stock (Lemprière et al 2013), and is an important source of wood fiber (Brandt et al 2013). Boreal forest is managed mostly for timber production but under the sustainable forest management paradigm, management aims to maintain the social, economic and ecological benefits of this important ecosystem (CCFM 1995). For a site to be considered productive in silvicultural terms, the total volume of wood with a merchantable size of stems must reach a certain quantity (Rapanoela et al 2015). At high latitude, both climatic and physical conditions (too wet or too dry) become limiting to tree growth to the point where sustainable forest management is no longer possible (Jobidon et al 2015; Robitaille et al 2015)

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