Improvements To The SORTIE ND / Prognosis BC Linked Model

Transcription

1 Improvements To The ND / Prognosis BC Linked ĈW Model ĈH Derek Sattler, M.Sc. Candidate Faculty of Forestry. University of British Columbia, Vancouver, Canada.

2 Sortie-ND Import Overstory + Understory tree list Note: Model Parameterized to study area ime 1 (After MPB attack) Sortie-ND New tree list following simulation New Seedlings + Saplings Timing of Handoff: 5, 10, 15 years Time 2 (Post MPB attack) Time 3 Prognosis BC Import same Overstory + Understory tree list as used in ND Note: Regen submodel turned off Prognosis BC New estimated tree list following projection Imputation from Prognosis BC Tree list composed of: 1) Prognosis BC projected overstory and understory 2) Seedlings and saplings provided via -ND

3 Background on Linked Model 1. What is it? Link between -ND and Prognosis BC 2. Why develop a link? Improve mid- to long-term Growth and Yield Projections Unmanaged, Naturally Regenerating Stands Uncertainty in G & Y projections following MPB

4 Linked Model Flow Sortie-ND - O/S + U/S tree list (from reconstructed stands) Time 1 (After MPB attack) Prognosis BC O/S + U/S tree list (from reconstructed stands) Sortie-ND New O/S +tree list following simulation New Seedlings + Saplings Time 2 (Post MPB attack) Prognosis BC New O/S+ U/S tree list following projection Imputation from Timing of Handoff 5, 10, 15 years Time 3 Prognosis BC O/S + U/S + New Seedlings projected in Prognosis

5 Model Simulations Five Simulations: 1. Seedling/Sapling Transfer AT YEAR 5 2. Seedling/Sapling Transfer AT YEAR Seedling/Sapling Transfer AT YEAR ND only No Transfer 5. Prognosis BC only No Transfer Total Projection Period = 25 years

6 Simulations Results: HAND-OFF AT YEAR 10 Best results were for Spruce and Aspen Seedlings + Saplings Seedling and Sapling Mortality rates estimated by were too high HANDOFF AT YR10 LODGEPOLE PINE HANDOFF AT YR10 SPRUCE AND ASPEN SPECIES 700 DBH CLASS DBH CLASS BIAS (PRED - OBS) BIAS (OBS - PRED )

7 Allometry Radiu s = A 1 DBH A 2 Heigh t = B 1 HEIGHT β 2 Independent of Stand Density Over-estimate Height/Radius in Dense Stands Under-estimate Height/ Radius in Open Stands

8 Improvements to Allometry 1. Include Measures of Density/Competition Improve fit over range of stand densities 2. Fit Height and Width as a System Avoid uncoupling Height + Width relationship 3. Functional Form: Ensure estimates were biologically attainable

9 Density/Competition Variables + Tree Level Variables Density/Competition Variables : Basal Area / Ha, Trees / Ha, Basal Area of Taller Trees (i.e., BA/Ha of trees taller then the ith-tree). Tree-level measurements: Height, DBH, Height, Width.

10 Height and Radius Strong CH CR relationship as a System Part of a simultaneous biological system Radius Estimate parameters via a system of equations Height Use Height + Radius as Dependent Regressors

11 Functional Form Height Model: Height = Height [ ] β X 1+ e Radius Model: i Radiu s = a X β

12 Chosen Models Estimate of Height = Height [ ] a+ DBH b+ Height c + Rad d+ BAL e+ Ba/Ha f + TPH g 1 + e i Estimate of Radius = a DBH b Height c Ht d BAL e Ba/Ha f TPH g

13 Results of Model Fit Overall Fit Statistics by Species: Summary of Fit Statistics for Pine Dependent Variable Height Radius Root MSE R-Square Partial R^2: Ba/Ha + Tr/Ha Root MSE Model R-Square Change in Estimate (Meters) Summary of Fit Statistics for Spruce Dependent Variable Height Radius Root MSE R-Square Partial R^2: Ba/Ha + Tr/Ha Root MSE Model R-Square Change in Estimate (Meters)

14 Overall Fit Statistics by Species: Summary of Fit Statistics for Douglas Fir Dependent Variable Height Radius Root MSE R-Square Partial R^2: Ba/Ha + Tr/Ha Root MSE Model R-Square Change in Estimate (Meters) Summary of Fit Statistics for Aspen Dependent Variable Root MSE R-Square Partial R^2: Ba/Ha + Tr/Ha Root MSE Model R-Square Change in Estimate (Meters) Height Radius

15 Sortie Equations Lodgepole Pine By Density Class (TPH) New Equations

16 Sortie Equations Interior Spruce By Density Class (TPH) New Equations

17 Sortie Equations Interior Douglas Fir By Density Class (TPH) New Equations

18 Sortie Equations Aspen By Density Class (TPH) New Equations

19 Pine New Model New Model Density Class (TPH) Mean Height Bias (meters) Mean Height Bias Mean Radius Bias (meters) Mean Radius Bias Spruce New Model New Model Density Class (TPH) Mean Height Bias (meters) Mean Height Bias Mean Radius Bias (meters) Mean Radius Bias

20 Douglas Fir New Model New Model Density Class (TPH) Mean Height Bias (meters) Mean Height Bias Mean Radius Bias (meters) Mean Radius Bias Aspen New Model New Model Density Class (TPH) Mean Height Bias (meters) Mean Height Bias Mean Radius Bias (meters) Mean Radius Bias

21 Summary of Results 1. Functional Form of Models Biologically Attainable 2. Addition of Competition / Density Variables Improved Fit Over a Wide Range of Stand Densities Use of Basal Area of Taller Trees 3. Height and Radius Fit as a System Unbiased estimates Efficient Parameter Estimation Avoids uncoupling of CH-CR relationship

22 Next Steps 1. Add New Equations to -ND Model 2. Obtain Parameter Estimates for Wider Range of Stands 3. Re-Run Linked Model (with new equations in )

23 Acknowledgments Funding: British Columbia Forest Science Program Supervisor: Dr. Valerie LeMay Committee Members: Peter Marshall, Bruce Larson, Dave Coates Prognosis Technical Support: Donald Robinson (ESSA), Abdel-Azim Zumrawi (BC-MOF)