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Conceptual Framework on Planning for Timber Supply
FORE 4212 Kevin Crowe
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Objectives of Lecture Overview timber supply planning
Step by step Place each step in conceptual context What does it mean? Big picture
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Topics of Discussion What is timber supply? How is it measured?
How do we estimate it? Model and data 7 steps Analysis Planning for timber supply
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What is Timber Supply ? A measure of the permitted flow of merchantable logs out of the forest into mills Pulled by price, governed by policy, limited by nature Component of forest management plan A bit of a misnomer Not standing stock
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Measure of Timber Supply
-AAC= planned cut level - every 5 years AAC LRSY LRSY = Σ (MAI * ha) of target forest What does this slope indicate ?
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Context of this problem
Great consequences Economic Environmental Social Great complexity Uncertainty Therefore, use a decision support model
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Since we use a model… What is a model?
A representation of reality that we hope to USE to understand that reality Used for convenience Typically categorized into abstract or concrete Timber supply models are abstract
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expressed quantitatively
How Does it Work? INSIGHT operative processes expressed quantitatively Real Managed System e.g., a forest Model Data
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What insight ? Learning about something through something else?
Learning through analogy A relation of likeness between things The relation between the model and the thing modeled is one of analogy Abstract models Simplified vs. conceptual
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Perhaps I digress, but… A critical distance is needed, and not always present You will use many models Conclusions drawn should be tempered by Quality of data Operative processes Room for improvement
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Let us return to… Decision support model for timber supply problem
There is a generic approach for building decision support models
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Decision Support Framework
Elicit Problem Decision Problem Formulate Model Collect/Enter Data Analysis Loop Generate Solution Choice… Action Appraise Solution
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Step 1 Elicit Problem Timber Objectives Portfolio of products
Product rests on economic assumptions Mill capacity/technology Silvicultural budget Potential Target Markets
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Step 1 Elicit Problem Social Objectives harvest flow policies
recreation and visual quality Various stakeholders
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Step 1 Elicit Problem Ecological Objectives
Common approach in B.C. and Ontario is
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Coarse filter -constraints operating at a variety of spatial scales -habitat for a broad range of wildlife -e.g. 80% clearcuts < 260 ha Fine Filter -required for species whose needs are not met by coarse filter
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Step Two Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Elicit Problem Appraise Solution
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Step 2 Formulate Model Mathematical formulation
Typically an optimization model Maximize NPV or Total Volume Subject to: social and ecological constraints In Ontario, the problem is modeled using SFMM
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Step 3 Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Elicit Problem Appraise Solution
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Step 3 Collect and Enter Data
Data preparation is over 85% of the effort Define Resource Inventories location of both timber and non-timber values Growth and yield Harvestable land base Final product is a spatial data base Polygons Define set of Potential silvicultural prescriptions
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Step 3 Collect and Enter Data
Defining the set of potential silvicultural prescriptions One of the most important decisions in forest management Emulation of natural disturbance is a guide.. Even-aged vs. uneven aged
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Step 3 Collect and Enter Data
Even aged decisions 1. Regeneration Method seed tree, shelterwood, clearcut and plant severity of disturbance probability of regeneration delay given seed tree 2. Rotation length(s) recall frequency of disturbance Age class distribution
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Step 3 Collect and Enter Data
Even Aged Decisions (cont’d) 3. Commercial Thinning The number and timing of entries 4 Opening size and shape Recall disturbance history, fragmentation 5. Trees to leave at final harvest Number and size of tress, snags, and down wood to be left in the opening 6. Adjacency Delay
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Step 3 Collect and Enter Data
Decisions needed in uneven-aged management 1. cutting cycle: number of years between harvest entry on a stand 2. Size of cutting compartments: the maximum size of contiguous area that can be entered at one time 3. reserve growing stock level: residual volume or basal area per acre that can be left
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Step 4 Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Elicit Problem Appraise Solution
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Step 4 Generate Solution
Apply an optimization algorithm to solve the model Generally two classes of algorithms Linear programming Used in SFMM Integer Programming Spatially explicit
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Step 5 Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Step 5 Elicit Problem Generate Solution Elicit Problem Appraise Solution
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Step 5 Appraise Solution
Assessing Timber and Non-timber Outputs Evaluate trade-offs Multiple objectives Use other analysis tools Collaborative effort
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Step 5 Appraise Solution
-e.g., input solution into analysis tools
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Step 5 Appraise Solution
OMNR’s Models to Evaluate Output Landscape Ecological Analysis Package (LEAP) Landscape Diversity Analysis (LDA) Regional Hydro Ecological Simulation System (RHESSys) Socio-economic Impact Model (SEIM)
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Step 6 Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Elicit Problem Appraise Solution
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Change these and solve again
Step 6 Analysis Loop Recall our model’s relation to reality modeled… Change these and solve again Operative Processes Real Managed System e.g., a forest Model Data
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Ecological Objectives
Step 6 Analysis Loop Ecological Objectives Multiply determined by uncertain factors Timber Supply Economic Objectives Social Objectives
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Step 7 Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Choice… Action Elicit Problem Appraise Solution
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Step 7 Choice of Plan Choice is fated
In reality, the long term plan will never be implemented LRSY is a guide to short term Plan, and then re-plan– in Ontario, every 5 years Adaptive management
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Step 7 Choice of Plan ACTION KNOWLEDGE Why plan without end?
To help make near-term actions and decisions consistent with: Dimly perceived future condition To learn about our ignorance of the managed system Knowledge and data gaps ACTION KNOWLEDGE “Models are to be used, not believed.” H. Theil `Principles of Econometrics'
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FINISHED Elicit Problem Formulate Model Collect/Enter Data
Analysis Loop Elicit Problem Generate Solution Choice… Action Elicit Problem Appraise Solution
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Conclusion Recall objectives of lecture Overview of modelling process
7 steps Understand conceptual context Model and Reality Decision support framework Analysis Loop Nature of Planning
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