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A national approach to the estimation of above ground biomass in forest trees, the Component Ratio Method (CRM). Mark Ha

A national approach to the estimation of above ground biomass in forest trees, the Component Ratio Method (CRM). Mark Hansen - NRS. Volume components in both FIADB3 & FIADB4. Trees < 5” have zero volume. Rotten or missing cull. Form cull or sound defect. Gross volume ( VOLCFGRS ) >=.

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A national approach to the estimation of above ground biomass in forest trees, the Component Ratio Method (CRM). Mark Ha

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  1. A national approach to the estimation of above ground biomass in forest trees, the Component Ratio Method (CRM).Mark Hansen - NRS

  2. Volume components in both FIADB3 & FIADB4 Trees < 5” have zero volume Rotten or missing cull Form cull or sound defect Gross volume (VOLCFGRS) >= Sound volume (VOLCFSND) >= Net volume (VOLCFNET)

  3. FIA biomass estimates • Tree level estimates of the biomass of all trees 1” diameter and larger on forest land. • Used to report total biomass at various levels. • Indirectly used to compute total carbon at various levels (carbon = biomass/2). • Not currently used to compute the growth, removals and mortality of biomass or carbon .

  4. Biomass components in FIADB3 Trees < 5” have zero DRYBIOM Rotten or missing cull Form cull or sound defect Total gross biomass (DRYBIOT) minus Merch. Biomass (DRYBIOM ) =Tops, limbs and stump

  5. Biomass components in FIADB4 Rotten or missing cull Form cull or sound defect --------------------------Trees 5”+ DBH --------------------------- Saplings Woodland species DRYBIO_BOLE DRYBIO_TOP DRYBIO_STUMP DRYBIO_SAPLING DRYBIO_WDLD_SPP All trees 1” diameter and larger DRYBIO_BG

  6. Biomass components in FIADB4 1” 2” 3” 4” 5” 6” 7” 8” ….

  7. Carbon components in FIADB4All trees 1” diameter and larger CARBON_AG CARBON_BG

  8. Regional volume computations • VOLCFGRS = fv(DIA,…) • VOLCFSND = VOLCFGRS – (observed or estimated rotten and missing cull) • VOLCFNET = VOLCFGRS – (observed or estimated total cull)

  9. Volume estimates have been one of our primary products for many years.

  10. Regional biomass computation • DRYBIOT = fb1(DIA,…) • DRYBIOM = fb2(DRYBIOT,…) or • DRYBIOM = fb3(VOLCFGRS,…) • DRYBIOT = fb4(DRYBIOM,…) • Biomass and volume equations take different forms and were developed at different times from different data sets.

  11. Issues • National consistency. • Biomass-volume consistency. • Errors in application of biomass equations. • Realistic estimates of components.

  12. Consistent - reasonable estimatesSelect red oak, 10.0” dia, live, growing stock trees, 60-70’ HT

  13. Jenkins et al. – total above ground biomass (including foliage)

  14. Biomass data sets • All the boles are strong • All the trees are good looking • All the SI are above average

  15. Component Ratio Method (CRM) • Based on the assumption that FIA volume estimates are pretty good. • Sound wood has biomass. • Rotten and missing wood has no biomass. • If we get the bole right, we are about 75% done.

  16. Biomass in the boleDRYBIOM in FIADB v3 DRYBIO_BOLE in FIADB v4 VOLCFSND (cf) x wood density (lbs/cf) + VOLCFSND (cf) x bark ratio (cf bark/cf wood) x bark density (lbs/cf)

  17. Biomass in the bole DRYBIO_BOLE DRYBIO_BOLE = VOLCFSND * WOOD_SPG * 62.4 + VOLCFSND * BARK_PCT * BARK_SPG * 62.4 = VOLCFSND * (WOOD_SPG + BARK_PCT * BARK_SPG) * 62.4

  18. Bole Bole biomass = (volume of sound wood in the bole) x (density of sound wood) + (volume of bark on the bole) x (density of bark)

  19. Biomass in the stumppart of (DRYBIOT-DRYBIOM) in FIADB v3 DRYBIO_STUMP in FIADB v4 DRYBIO_BOLE (lbs) x Jenkins biomass in stump (lbs) / Jenkins biomass in bole (lbs)

  20. DRYBIO_STUMP DRYBIO_STUMP = VOLCFSND * (WOOD_SPG + BARK_PCT * BARK_SPG) * 62.4 * ( raile_stump_b1*dia*dia / (((exp(jenkins_stem_bark_ratio_b1 + jenkins_stem_bark_ratio_b2 /(dia*2.54)) + (exp(jenkins_stem_wood_ratio_b1 + jenkins_stem_wood_ratio_b2 /(dia*2.54)))) * (exp(Jenkins_TOTAL_b1 + jenkins_TOTAL_b2 * ln(dia*2.54))))) )

  21. Stump Stump biomass = Bole biomass x Stump ratio

  22. Biomass in the tops and limbspart of (DRYBIOT-DRYBIOM) in FIADB v3 DRYBIO_TOP in FIADB v4 DRYBIO_BOLE (lbs) x Jenkins biomass in branches (lbs) / Jenkins biomass in bole (lbs)

  23. Tops and limbs Top and limb biomass = Bole biomass x Branch ratio

  24. Saplings (trees < 5.0” diameter) • CRM is Jenkins adjusted to meet national average CRM biomass of a 5.0” diameter tree by species group. • Smooth transition over the 5” threshold is important for growth estimation. • DRYBIOT in FIADB v3 • DRYBIO_SAPLING in FIADB v4

  25. What follows are Regional vs CRM vs Jenkins estimates for each FIA region by state • All estimates are based on the latest/greatest public version of FIADB (as of Oct 2008). • All estimate are total above ground biomass of live trees 5” diameter and larger on forest land. • Annual estimates for 47 states, mostly 2007 and 2006, a few 2005. • New Mexico – 1999 periodic inventory is include. • Oklahoma and Hawaii are missing.

  26. Hardwoods4.0” to 6.0”diameter

  27. Softwoods4.0” to 6.0”diameter

  28. CRM estimatesSelect red oak, 10.0” dia, live, growing stock trees, 60-70’ HT

  29. What next – the future of CRM • All the species level coefficients used to compute components will be stored in FIADB v4. • Better (taper based) volume estimates will improve the CRM estimate of biomass. • Taper based estimates of stump volume. • Improved estimates of bark volume. • Other estimates of the biomass in tops and limbs .

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