Using expert judgments to explore robust alternatives for forest management under climate change By Tim McDaniels University of British Columbia and CEDM.

Using expert judgments to explore robust Using expert judgments to explore robust alternatives for forest management under alternatives for forest management under

climate change climate change

ByBy

Tim McDanielsTim McDanielsUniversity of British ColumbiaUniversity of British Columbia

and CEDMand CEDM

AcknowledgementsAcknowledgements

Thanks to the CEDM and National Thanks to the CEDM and National Science Foundation for supportScience Foundation for support

Thanks to co-authors Tamsin Mills, Robin Thanks to co-authors Tamsin Mills, Robin Gregory and Dan OhlsonGregory and Dan Ohlson

Thanks to participants, and to Bruce Thanks to participants, and to Bruce Blackwell and Cindy Pearce for forestry Blackwell and Cindy Pearce for forestry advice and insightsadvice and insights

HighlightsHighlights

First paper on RDM using expert judgments First paper on RDM using expert judgments (forthcoming, Risk Analysis)(forthcoming, Risk Analysis)

Develops a framework for elicitation based on Develops a framework for elicitation based on DA concepts: objectives, alts, Likert scales for DA concepts: objectives, alts, Likert scales for performance measures of consequences, given performance measures of consequences, given different climate scenariosdifferent climate scenarios

Results show two alternatives consistently Results show two alternatives consistently outperform the current status quooutperform the current status quo

Results are broadly consistent, and indicate Results are broadly consistent, and indicate promise for this approachpromise for this approach

80% Volume of Pine killed on 80% Volume of Pine killed on the Timber Harvesting Land the Timber Harvesting Land

Base by 2014Base by 2014

Maps: Government of BC

ChallengesChallenges

Photo: nrcan

Photo: mountaincaribou.org

MPB DriversMPB Drivers

““significant increase significant increase in infestations in infestations occurring in areas occurring in areas that were historically that were historically climatically unsuitable climatically unsuitable for the beetle.for the beetle.”” (CFS) (CFS)

Infestations are Infestations are climate exacerbated climate exacerbated (along with previous (along with previous management choices)management choices)

Photo: watersecretsblog.com

Expected Impacts of Climate Change

Concepts and objectivesConcepts and objectives

Robust DM has great appeal as a Robust DM has great appeal as a response to irreducible uncertaintyresponse to irreducible uncertainty

The analytical and information demands The analytical and information demands are enormousare enormous

The intent here is to explore the feasibility The intent here is to explore the feasibility of judgmental approaches to identifying of judgmental approaches to identifying robust alternatives in a specific climate robust alternatives in a specific climate adaptation decision context: how to adaptation decision context: how to manage land after the infestationmanage land after the infestation

Robust DM criteriaRobust DM criteria

An array of definitions, used in various contextsAn array of definitions, used in various contexts Here: “..reasonably likely to achieve objectives, over a range of Here: “..reasonably likely to achieve objectives, over a range of

uncertainties”uncertainties” Here the uncertainty addressed is climate uncertainties, with three Here the uncertainty addressed is climate uncertainties, with three

scenarios: low to highscenarios: low to high

Structured Decision Making

Source: Ohlson et al 2005

Elicitation conceptsElicitation concepts

Group elicitation of three point probabilities Group elicitation of three point probabilities over the consequences of alternatives in over the consequences of alternatives in terms of selected objectivesterms of selected objectives

Informed by concepts for improving Informed by concepts for improving judgmental forecasting: graphical judgmental forecasting: graphical communication, combining forecasts, communication, combining forecasts, specify scenarios, avoid bias and specify scenarios, avoid bias and overconfidence etc overconfidence etc (Stewart and Lusk)(Stewart and Lusk)

Workbook /WorkshopWorkbook /Workshop

Elicit expert judgementsElicit expert judgements Purposive SamplingPurposive Sampling Pilot testPilot test Workshop (n=14 after one rejection)Workshop (n=14 after one rejection) Workbook:Workbook:

Defining the problem: study areaDefining the problem: study area Management ObjectivesManagement Objectives Climate Change scenarios Climate Change scenarios Introducing alternativesIntroducing alternatives Evaluate the strategies; judgementsEvaluate the strategies; judgements

Climate Change ScenariosClimate Change Scenarios

ObjectivesObjectives

AlternativesAlternativesStrategy TablesStrategy Tables

Judgements

Analysis approachesAnalysis approaches

Examine the patterns for each person (one Examine the patterns for each person (one rejected)rejected)

Examine the distributions (none bimodal)Examine the distributions (none bimodal) Combined forecasts (averaging at first)Combined forecasts (averaging at first) Conducted extensive sensitivity analysis Conducted extensive sensitivity analysis

(varying weights on each objective)(varying weights on each objective) Examined individual preferred alternatives Examined individual preferred alternatives

(consistent with averaged results)(consistent with averaged results)

FindingsFindings

Two closely related alts widely seen as most Two closely related alts widely seen as most robust over the climate uncertaintyrobust over the climate uncertainty

The current status quo policy performs worstThe current status quo policy performs worst The more robust alts have higher performance in The more robust alts have higher performance in

part due to more flexibility and diversity on the part due to more flexibility and diversity on the ground (like findings of analytical RDM)ground (like findings of analytical RDM)

This is an encouraging method that deserves This is an encouraging method that deserves further workfurther work

How were judgements How were judgements affected by time period, affected by time period, objectives and climate objectives and climate

change scenarios?change scenarios?

UncertaintyUncertainty