Timber Harvest Scheduling (Tactical planning) • Tactical problem • Handle large problems – 100 000 roads – ~20 000 stands – Seasons x 5 years => ~20 time periods – 3 road

Timber Harvest Scheduling (Tactical planning)

www.treesys.se

www.treesys.se

www.treesys.se

Contents

• Requirements• The planning problem• Software development• Demo

Requirements

• Tactical problem • Handle large problems

– 100 000 roads– ~20 000 stands– Seasons x 5 years => ~20 time periods– 3 road upgrade options

• Solvable within 24 hours• GIS• Easy to use (district manager) • Possible to sell

Requirements Problem Software developm. Demo

1. Learn2. Understand3. Install4. Start (open projekt/session)5. Import data6. Define problem7. Run problem8. Read/manage results

Easy to use = Easy to:

Requirements Problem Design Demo

Model features

• Road upgrading• Harvest scheduling• Stand accessibility (soil bearing)• Road accessibility• Forwarding cost• Even-flow• Demand


Stand Year Season

1 ? ?

2 ? ?

3 ? ?

…5‐year set of standsto be harvested Road Year Season Upgrade

to

1 ? ? ?

2 ? ? ?

3 ? ? ?

…


Objective function

MinimizeTotal road upgrading (discounted)+Total forwarding cost (discounted)


Public road

Forest roadsegments

Stand B

Stand A

Stand C

Building the road network - routesRequirements Problem Software developm. Demo

Roads in short

• Stand => hauling road• Hauling road => route• Route => road classes


Route logics

• Roads in a route used in a certain season must all have a certain minimum road class for the season

• Roads have state and upgrade variables

• A stand-specific hauling road must be activated if a stand is harvested. At least one route that the terrain road connects to must be activated

• ”Clique constraints”: Dominating routes


Software components

• Matrix generation – new matrix generator (C#)• Solver independent (LP format)• Gurobi, Xpress, Cplex• Road network and GIS – DotSpatial• Shortest path – QuickGraph• UI – DevExpress• Database mapping – DevExpress XPO


New modelling API (LP-writer)

_areaConstraint = new CliqueConstraint(_optModelWriter, "Area", _harvestDecisions, _standSet );

_harvestDecisions = newBinaryDecisionVariable(_optModelWriter, VariableNames.HARV_DEC2, _standSet.Union(_periodSet));


Open source project?

LP-writer features

1. Set, Constraint, Variable, Coefficent object types + derived types2. Foreach3. Slicing4. Time offset5. Sparse matrix6. Slack variables7. “Accounting” variables8. “Objective function accounting variables”9. In my opinion, much easier than


Third part commercial components

• State-of-the art solvers pricing repellent to small companies• Royalty-based an option. Cloud-services emerging, but IMHO not

”there” yet• Modelling tools also expensive (GAMS, AMPL, AIMMS)• DevExpress – royalty free, 600 USD per developer


Deployment• Code objfuscation • Licensing and license server

– Free trial– Academic– Business

• Solver licensing• Installation package• EULA, third part components• Help documentation• Support desk• Payment routines














www.treesys.se

Problem specs

• 11 000 stands x 20 periods• 400 000 road features x 4 classes x 20 periods• Routes• 11 000 x 3 alternative hauling roads x 20 periods


Documents

Timber Harvest Scheduling (Tactical planning) • Tactical problem • Handle large problems – 100 000 roads – ~20 000 stands – Seasons x 5 years => ~20 time periods – 3 road