Combining carbon sequestration objectives with timber management planning

Abstract

This paper presents a new approachto assessing carbon (C) sequestration incommercial forests at spatial scalesrelevant to forest managers. The approachcombines C-sequestration objectives withtimber and non-timber (i.e., wildlifehabitat) management objectives. As ademonstration, the approach is applied to a105,000 ha special management area innorthern New Brunswick, Canada over asimulated time horizon of 80 years. Carbonstock calculations are carried out bymultiplying a series of simple woodvolume-to-C conversion factors to woodsupply projections generated with theWoodstock™ wood supply (RemSoft Inc.) andCWIZ™ linear programming software. Basicinput requirements to the wood supply modelinclude (i) current forest stand inventoryand forest age structure, (ii) growth andyield curves for naturally developingstands, (iii) modified growth and yieldcurves to describe post-treatment standresponse, (iv) non-timber objectives, and(v) specific harvesting prescriptions,including extent of application area andintensity. Spatial blocking of stands iscarried out by importing the treatmentschedule from the 80-year plan and byproviding spatial constraints such asgreen-up delays and adjacency rules over a25-year planning horizon. Model projectionindicates that C stock in the forestof the special management area willincrease in the next 40 years under theproposed harvesting plan and start todecrease thereafter. Under theno-disturbance scenario (both natural andman-made), the carbon stock in the forestwill increase for the next 60 years andstart to decline thereafter. For the wholeplanning period, carbon stock in the forestfollowing current industrial practices willbe less than naturally growing forestwithout any form of disturbance.Although model calculations are notexact, combining C objectives with timbermanagement objectives provides a goodframework for assessing C sequestration incommercial forests, given the excellentquality of the forest input data regardingabove ground biomass. Improvements tomodelled C-sequestration projections maytake place as scientific information aboutthe details of the C cycle in managedforests becomes available.