harvest scheduling and policy analysis

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Harvest Scheduling & Policy Analysis

Karl R. Walters,Forest Planning Manager, Forest Technology Group

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In this section…

We will review terminologyOutcomesConditionsActivitiesLinear programming (LP)

Develop a base LP model for the Daniel Pickett forestStratificationYieldsActions & Transitions

Make changes to the base model to evaluate different policies

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Terminology Review

OutcomesMore traditional outputs of economic goods & services

Timber harvest volume, recreational visitor days, forage in AUM’s, etc.

ConditionsCurrent & future spatial and element structure of forest ecosystem

Area by stand or habitat type, # of snags/ac, road densities, etc.

ActivitiesHuman related disturbances occurring on the forest

Harvest acres, prescriptions used, miles of road built, etc.

Any of these can be viewed as positive or negative depending on goals

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Terminology Review

Linear programmingConstrained optimization problems

Without constraints, there is no LP problem

Allocation or scheduling of scarce resourcesKey assumptions

Linearity: relationships are strictly linearIf you double the acres harvested, the volume harvested also doubles

Divisibility: any fractional quantity is allowedAny fractional acre can be harvested; otherwise is mixed-integer programming (MIP)

Deterministic: all coefficients are known with certainty

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Daniel Pickett Forest*

Could be anywhereSpecifics of site quality, location & species not identified

2500 acres1000 ac = good site, well stocked, healthy, 100 yrs (old growth)500 ac = poor site, cutover, diseased, 100 yrs (old growth)1000 ac = poor site, well stocked, healthy, 10 yrs (young growth)

*

Based on material from Davis et al., Forest Management,

4th

ed. 2001. Chapters 3 & 12.

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Daniel Pickett Forest

3 WatershedsDogwood CreekTrout CreekWhitewater Creek

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Streamside Management Zones100 ft buffers

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2 Site ClassesGood (red)Poor (green)

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Stand ConditionHealthy, well stocked (green)Diseased, cutover (red)

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Existing Forest CharacteristicsMixed forest type*WatershedManagement emphasis (timber production vs SMZ)Site quality*Stand Condition*Harvest Units

* drivers of growth & yield

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DP Resource Capability Model

Known Management Objectives/ConstraintsMaximize net present value of forest using 4% discount rateHarvest volume not to vary by more than 20% period-to-periodAt least 200 ac must be set aside in park-reserve statusAt least 100 contiguous acres of existing healthy old growth must be set aside as uncut park to protect the habitat of endangered owlNo more than 700 ac can be harvested in each of the first 3 periods to give a good distribution of area by agesEven-aged prescriptions should not exceed 40% of total forestClearcut prescriptions = no more than 20% of forest area and no more than 30% of each watershedDesired future conditions based on WHR system

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Outcomes & Activities (Outputs)PNV (4%)Harvest volumeAcres in park-reserve statusAcres in owl habitat statusAcres harvestedAcres clearcut harvestedAcres in evenaged Rx’sAcres clearcut in each watershed (spatial constraint)

Model codesOFpnv4OQvolOAreserveOAowlOAharvOAccOAevenOAccdc, OAcctc OAccwwc

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Desired future conditionsBased on Wildlife Habitat Relationship classification

Species (1 class – mixed species)Size class (6 diameter classes)Stand density (2 classes)

DFC in period 8No more than 20% change period-to-period thereafter

OutcomesAcres within each desired WHR class

OAm1m, OAm1d (250 ac @8)OAm2m, OAm2d (250 ac @8)OAm3m, OAm3d (500 ac @8)OAm4m, OAm4d (750 ac @8)OAm5m, OAm5d (250 ac @8)OAm6m, OAm6d (500 ac @8)

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Four Management Prescriptions (Activities)Rx1=even-age, 30 yr rotation, plant & regeneration harvest in 30 yr

All stand types are eligible for this prescription

Rx2=even-age, 40 yr rotation, naturally regenerate with supplemental planting if need, commercial thin at age 20, regeneration harvest at age 40

Only good sites are eligible for this prescription

Rx3=even-age, 90 yr rotation, plant & regeneration harvest in 90 yrAll stand types are eligible for this prescription

Rx4=uneven-age, small group selection, 2-ac or smaller openings, 60 yr rotation (enter 1/6 of area assigned to Rx each decade, regeneration harvest at age 60

Only good sites are eligible for this prescription

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Stumpage RevenuesHealthy old growth= $4/cu ftDiseased old growth= $2/cu ftYoung growth= $2.50/cu ft

Site prep/RegenGood sites= $500/acGood sites= $300/ac

Management feesGood sites= $30/ac/decadePoor sites= $20/ac/decade

Logging CostsHealthy old growth, on good sites = $1.00/cu ftDiseased old growth, on poor sites = $1.50/cu ftHealthy young growth on good sites = $0.75/cu ftHealthy young growth on poor sites = $1.25/cu ft

Discount rate4% discounted to middle of planning period

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DP RCM –

Base

Planning Horizon _LENGTH = 12 decades

Objective_MAX OFpnv4 _LENGTH

ConstraintsNone: pure profit maximizationTotal forest acres = 2500 (LP constraint but always assumed)

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DP RCM –

Base

ResultsPNV = $10,852,028Maximum volume change period-to-period = +∞,-100% (<20%)100% of forest in evenaged Rx’s (<40%)Maximum acres clearcut in 1st three periods = 443.92 (<700)100% of Dogwood Crk assigned clearcut Rx (<30%)100% of Whitewater Crk assigned clearcut Rx (<30%)100% of Trout Crk assigned clearcut Rx (<30%)0 ac assigned park-reserve status (>200)0 ac assigned to uncut owl habitat preservation (>100)

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DP RCM –

Policy 1 (original DP)

Original Daniel Pickett problem (Chapter 11)Planning Horizon

_LENGTH = 12 decadesObjective

_MAX OFpnv4 _LENGTHConstraints

OAreserve >= 200 1 ; at least 200 ac in park-reserve statusOAowl >= 100 1 ; at least 100 ac of existing good old growth uncut for owls_SEQ(OQvol,0.2,0.2) 1.._LENGTH ; harvest volume to vary by < 20%OIGvol >= 5000000 _LENGTH ; preharvest inventory[12] > 5000000OAcc <= 700 1..3 ; no more than 700 ac clearcut harvested in 1st 3 periodsOArx2 >= 400 _LENGTH ; at least 400 ac of Rx 2 assigned

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DP RCM –

Policy 1

ResultsPNV = $8,279,139Maximum volume change period-to-period = 20% (<20%)Maximum acres clearcut in 1st three periods = 700 (<700)200 ac assigned park-reserve status (>200)100 ac assigned to uncut owl habitat preservation (>100)Preharvest inventory in last period = 5,000,000 (>5,000,000)92% of forest in evenaged Rx’s (<40%)100% of Dogwood Crk assigned clearcut Rx (<30%)93% of Whitewater Crk assigned clearcut Rx (<30%)83% of Trout Crk assigned clearcut Rx (<30%)

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DP RCM –

Policy 2

ConstraintsOAreserve >= 200 1 ; at least 200 ac in park-reserve statusOAowl >= 100 1 ; at least 100 ac of existing good old growth uncut for owls_SEQ(OQvol,0.2,0.2) 1.._LENGTH ; harvest volume to vary by < 20%OIGvol >= 5000000 _LENGTH ; preharvest inventory[12] > 5000000OAcc <= 700 1..3 ; no more than 700 ac clearcut harvested in 1st 3 periodsOArx2 >= 400 _LENGTH ; at least 400 ac of Rx 2 assigned OAeven <= 1000 1.._LENGTH ; no more than 40% of forest in evenaged RxsOAcctc <= 0.3 * OAtc _LENGTH ; acres clearcut in Trout Crk < 30% of watershedOAccdc <= 0.3 * OAdc _LENGTH ; acres clearcut in Dogwood Crk < 30% of watershedOAccwwc <= 0.3 * OAwwc _LENGTH ; acres clearcut in Whitewater Crk < 30% of watershed

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DP RCM –

Policy 2

ResultsPNV = $4,006,265Maximum volume change period-to-period = 20% (<20%)Maximum acres clearcut in 1st three periods = 700 (<700)200 ac assigned park-reserve status (>200)100 ac assigned to uncut owl habitat preservation (>100)Preharvest inventory in last period = 5,000,000 (>5,000,000)30% of forest in evenaged Rx’s (<40%)30% of Dogwood Crk assigned clearcut Rx (<30%)30% of Whitewater Crk assigned clearcut Rx (<30%)30% of Trout Crk assigned clearcut Rx (<30%)

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DP RCM –

Policy 1

Desired Future ConditionsAcre proportions of period 8Sequential change in proportions thereafter < 20%

OAm1m/OAm1d (250 ac @8)OAm2m/OAm2d (250 ac @8)OAm3m/OAm3d (500 ac @8)OAm4m/OAm4d (750 ac @8)OAm5m/OAm5d (250 ac @8)OAm6m/OAm6d (500 ac @8)

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DP RCM –

Policy 1

Habitat Composition

0

500

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10 11 12

Planning Period

Acr

es o

f Hab

itat T

ype

M6DM6M

M5DM5M

M4DM4M

M3DM3M

M2DM2M

M1DM1M

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DP RCM –

Policy 2

Habitat Composition

0

500

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10 11 12

Planning Period

Acr

es o

f Hab

itat T

ype

M6DM6M

M5DM5M

M4DM4M

M3DM3M

M2DM2M

M1DM1M

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DP RCM –

Policy 3

Constraints*OBJECTIVE_GOAL(g1,g2,g3,g4,g5,g6) ; minimize deviations from WHR goals*CONSTRAINTSOAreserve >= 200 1 ; at least 200 ac in park-reserve statusOAowl >= 100 1 ; at least 100 ac of existing good old growth uncut for owlsOIM6 = 500 _GOAL(G6,1,1) 8OIM5 = 250 _GOAL(G5,1,1) 8OIM4 = 750 _GOAL(G4,1,1) 8OIM3 = 500 _GOAL(G3,1,1) 8OIM2 = 250 _GOAL(G2,1,1) 8OIM1 = 250 _GOAL(G1,1,1) 8

Constraints (cont’d)_SEQ(OIM6,0.2,0.2) 9.._LENGTH_SEQ(OIM5,0.2,0.2) 9.._LENGTH_SEQ(OIM4,0.2,0.2) 9.._LENGTH_SEQ(OIM3,0.2,0.2) 9.._LENGTH_SEQ(OIM2,0.2,0.2) 9.._LENGTH_SEQ(OIM1,0.2,0.2) 9.._LENGTH

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DP RCM –

Policy 3

ResultsPNV = $229,564Maximum volume change period-to-period = -50%,+147% (<20%)Maximum acres clearcut in 1st three periods = 302 (<700)200 ac assigned park-reserve status (>200)100 ac assigned to uncut owl habitat preservation (>100)Preharvest inventory in last period = 5,002,078 (>5,000,000)40% of forest in evenaged Rx’s (<40%)50% of Dogwood Crk assigned clearcut Rx (<30%)41% of Whitewater Crk assigned clearcut Rx (<30%)28% of Trout Crk assigned clearcut Rx (<30%)

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DP RCM –

Policy 3

Habitat Composition

0

500

1000

1500

2000

2500

0 1 2 3 4 5 6 7 8 9 10 11 12

Planning Period

Acre

s of

Hab

itat T

ype

M6DM6MM5DM5MM4DM4MM3DM3MM2DM2MM1DM1M

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DP RCM –

Policy 3

Why can’t we meet DFC?None of the Rx’s will produce M6M/M6D – only existing good old growth has it so it must be largely left unharvestedFew Rx’s produce early WHR typesSome constraints are too onerous

What do we need to do?Develop new silvicultural Rx’s that can produce M6M/M6D types

Possibly find better growth & yield models to predict WHRExplore additional scenariosModify constraints

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FeaturesScheduled:

Clearcut final harvest, group selection, commercial thinningNatural and artificial regenerationSome variations of DP RCM not shown included fertilization

Tracked Volume outputs, revenues, costsActivity levels (acres treated)Wildlife Habitat Relationship classification acresCould easily track products, forage acres, etc.

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Forest Management Planning

What is required?Computer hardware

Fast CPU, lots of memory, disk space (all much cheaper in recent years)Computer software

Forest planning modelsCommercial products: Woodstock, Ep(x), HabplanPublic Domain: Spectrum (FORPLAN), SARA

Growth & Yield modelsStand-level for volume/product outputsIndividual tree models for habitat/ecosystem variables

Geographic Information/InventorySufficient and Complete

ExpertiseSubject matter experts in economics, biometrics, forest management, GIS

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Visualization

Today

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Visualization –

20 years later

20-years into future

20-years into future

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Part 3 –

Questions & Answers

In this section…We will open up the discussion to questions from audience

What planning problems can I address using this technology?How do I incorporate this facet of the problem into a forest planning model?How do I go from a strategic planning model to something I can implement on the ground?

Discuss issues on technology and expertiseShould I do this stuff in-house, or should I contract it out?

Final take-away points

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Issues

Hardware is probably the cheapest aspectCapacity continues to growData availability is often more limiting

Access to growth & yield modelsPlot dataResearch and Development

In-house R&D, membership in cooperatives, public domainExpertise

Requires a group of experts working togetherLimited supply

Relatively few people available with the training/experience needed

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Final Thoughts –

7 Points

Know the long-term & short-term goals of the landowner/decision-maker. Are these priorities documented?Establish the time-frame for the analysis. Next year? Next 10 years? Next 20-50 years? All of these?Do you need to consider county, state, federal laws or regulations? Do outside interests need to be recognized in your plan?Is spatially-explicit information needed for implementation?Critically evaluate your available data. Is it sufficient and complete to meet your planning needs?How will your silvicultural prescriptions be generated? How will you generate estimates of outcome arising from them?Who are the people that will be doing this work for you? Are they in-house specialists? Out-sourced specialists? Combinations?

harvest scheduling and policy analysis

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