Enhancing Forest Inventory and Biomass Variables: Current Status and Future Needs

1. FIA Volume and Biomass Variables: A Look at Current Status and Needs Raymond M. Sheffield Southern Research Station Larry DeBlander Rocky Mountain Research Station Photo Credit: Mary Ann Fajvan, West Virginia University, www.forestryimages.org

2. Objectives • Review current volume/biomass variables • Review inconsistencies/limitations • Changes needed to correct problems/voids • List possible new variables to address current needs • Next steps

3. Background • Volume/Biomass Variables Definition Team • Multiple Band Membership (AB, IM, DAB) • Goals: • Which of the present FIADB volume/biomass variables are needed? • Which are national or regional in nature? • How to define, document, field collect, calculate, and populate the needed variables? • Brief Summary of Work to Date

4. Current Volume/Biomass Tree Variables • VOLCFNET • For trees with d.b.h. >= 5.0 inches, net cubic-foot volume in central stem from 1-ft stump to a 4-inch top d.o.b. • Gross merchantable volume minus cull deductions • VOLCFGRS • As above but without cull deductions 4-inch top d.o.b Merchantable portion 1-foot stump

5. Current Volume/Biomass Tree Variables • VOLCSNET • Net cubic-foot volume in the saw-log portion of sawtimber size, growing stock trees • VOLCSGRS • As above but without cull deductions 4.0 inch top d.o.b. Saw-log top Saw-log portion

6. Current Volume/Biomass Tree Variables • VOLBFNET • Net board-foot volume in the saw-log portion of sawtimber size, growing stock trees • VOLBFGRS • As above but without cull deductions 4.0 inch top d.o.b. Saw-log top Saw-log portion

7. Current Volume/Biomass Tree Variables • DRYBIOM • For trees with d.b.h. >= 5.0 inches, merchantable stem biomass in oven-dry weight. • Gross biomass including bark in central stem from 1-ft stump to a 4-inch top d.o.b. 4-inch top d.o.b Merchantable portion 1-foot stump

8. Current Volume/Biomass Tree Variables • DRYBIOT • The total aboveground gross biomass of a sample tree 1.0 inch diameter or larger, including all tops and limbs (Oven-dry weight) • Excludes foliage • Only volume/biomass variable populated for trees < 5.0 inches

9. Inconsistent Definition/Calculation • Western woodland species not accommodated in definitions • Cull (defect) deductions vary widely • Lack of national core Tree Class variable affects all Growing Stock variables, especially Sawtimber • Salvable Dead class of timber not nationally defined • Biomass variables

10. Western Woodland Species:Where’s the Merchantable Portion? Merchantable portion

12. More inclusive definition… • Volcfnet: The net cubic-foot volume of the merchantable portionof a live tree 5.0 inches diameter or larger. • Merchantable portion: • That portion of the central stem of a timber species tree from a 1-foot stump to a minimum 4-inch top diameter, or to where the central stem forks, where all are less than 4.0 inches diameter, OR • That portion of a woodland species tree from the DRC measurements to the 1.5-inch ends of all the qualifying stems.

13. Inconsistent Definition/Calculation • Western woodland species not accommodated in definitions • Cull (defect) deductions vary widely (dead trees esp. problematic) • Lack of national core Tree Class variable affects all Growing Stock variables, especially Sawtimber • Salvable Dead class of timber not nationally defined • Biomass variables

14. Cull (defect) deductions vary widely • Volcfnet: a cubic foot value populated by deducting both sound and rotten/missing cull for some FIA units; others only deduct rotten/missing • Broken stems cause major inconsistencies

15. 4.0 inches d.o.b. Sound cull Merchantable portion

16. Proposed definition of “net” cubic volume • Net cubic-foot volume - Gross cubic-foot volume minus deductions for rotten/missing cull

17. Other Problems with Cull Deductions 4.0 inches d.o.b. Missing top Merchantable portion Rotten or missing

18. Rotten/Missing Wood Not Collected For Dead Trees in Some Regions (Core Optional) Photo: Chris Schnepf, University of Idaho, www.forestryimages.org

19. Inconsistent Definition/Calculation • Western woodland species not accommodated in definitions • Cull (defect) deductions vary widely (dead trees esp. problematic) • Lack of national core Tree Class variable affects all Growing Stock variables, especially Sawtimber • Salvable Dead class of timber not nationally defined • Biomass variables

20. What are we missing? • “Net” biomass estimates • Do we need to distinguish “missing” wood from “decayed” wood? • Standing dead trees < 5.0 inches d.b.h. • Estimates of green biomass • Total tree stem volume and biomass

21. Let’s Move Beyond Outdated Merchantability Standards 4.0 inches d.o.b. Total Stem Volume/Biomass Merchantable portion Saw-log portion

22. New Variables Coming Your Way? • VOLCFSTEMNET: Net cubic-foot volume of the main stem of a tree 1.0 inch diameter or larger. • VOLCFSTEMGRS: Gross-cubic foot volume of the main stem of a tree 1.0 inch diameter or larger. • DRYBIOSTEMNET: Net above ground biomass of the main stem of a tree 1.0 inch diameter or larger (oven dry weight). • DRYBIOSTEMGRS: Gross above ground biomass of the main stem of a tree 1.0 inch diameter or larger (oven dry weight).

23. New Variables: “Net” Biomass • DRYBIOTNET: Net above ground biomass of a tree 1.0 inch diameter or larger (oven dry weight). • DRYBIOMNET: Net above ground biomass of the merchantable portion of a tree 5.0 inches in diameter or larger (oven dry weight).

24. National Volume Equations • Encourage development and testing of national equations for volume and biomass • VOLCFNETNAT: National FIA variable to house results of national equations to facilitate testing/validation.

25. Other Recommendations • Make Tree Class (and Growing Stock) National Core • Conduct more “all live” and total biomass analysis now so we aren’t limited to growing stock trends in the future

26. What’s Next? • Change Proposals !!!!!!!!! • Revise Change Component Variables