Northwest Advanced Renewables Alliance How do residual biomass removals affect long- term forest productivity?: Long-term Soil Productivity (LTSP) studies Scott M. Holub, Ph.D. Silviculture Research Scientist Weyerhaeuser Company Springfield Oregon February 18, 2015 MOSS Imagine Tomorrow Webinar

1 OBJECTIVE OF TODAY'S PRESENTATION Briefly describe Weyerhaeuser Company and the processes we use to achieve sustainable site productivity and meet stewardship objectives to:  minimize soil erosion and harmful soil disturbance  maintain or enhance organic matter and soil nutrition Present information about two studies looking at the effects of biomass removal on Long Term Soil Productivity.

WEYERHAEUSER IS ONE OF THE WORLD’S LARGEST PRIVATE FOREST LANDOWNERS AND HARVEST ONLY A SMALL PERCENTAGE EACH YEAR ~2.5 million acres in western Oregon and Washington

5 WEYERHAEUSER FORESTRY Weyerhaeuser Forestry has resource strategies for: -Forest Products -Water Quality -Wildlife Habitat -Soil Productivity

6 WEYERHAEUSER FORESTRY Commitment to sustainable forestry: Soil is an integral part of the forest – no crop can be managed sustainably without considering the soil that supports it.

7 Organic Matter/Soil Nutrient - Management Principles Conserve organic matter/nutrients throughout the managed forest cycle Balance nutrient inputs/outputs through successive rotations Follow Best Management Practices

8 SOIL & NUTRIENT MANAGEMENT PRINCIPLES Loss of topsoil and associated litter layers can reduce soil productivity potential by: Reducing organic matter - reduces moisture holding capacity/infiltration Relocating nutrients -- leading to localized areas of low soil fertility

9 Soil aeration and macro-pore space are critical determinants of soil productivity: – Soil compaction can be detrimental, neutral, or beneficial depending on the level of pore space and texture of the undisturbed soil and the degree of macro-pore space – Disruption of pore space continuity can also impact water movement SOIL & NUTRIENT MANAGEMENT PRINCIPLES

10 Soil productivity potential can be enhanced: Compacted soil layers -- soil cultivation Nutrient deficiencies -- nutrient amendments SOIL & NUTRIENT MANAGEMENT PRINCIPLES

11 NARA Biomass Removal Research

12 WHAT IS NARA? Northwest Advanced Renewables Alliance NARA is the name given to the group of organizations involved in a $40 million biofuel grant from USDA AFRI. Goal: Convert Douglas-fir woody biomass to jet fuel.

13 ENVIRONMENTAL SUSTAINABILITY Part of NARA’s Mission: … meet the high environmental standards of the Pacific Northwest.

14 | 8/13/2014 SOIL PRODUCTIVITY/SLASH REMOVAL Concern: Removing slash removes nutrients and compacts soil. Question: Does slash harvest for biofuel feedstock affect future site growth capacity? Implications: Sustainability / Carbon neutrality / Policy

15 LONG TERM SOIL PRODUCTIVITY NETWORK Map Credit: Andy Scott, USFS Regional Studies in Coastal Douglas-fir Matlock, WA Fall River, WA Molalla, OR NARA LTSP

16 NARA LTSP TIMELINE 2012 – Site indentified/plotted – 83 acres near Springfield, Oregon acre plots. Soil nutrients (June/July) / Pre-harvest tree, etc. measurements (Sept/Oct) – Harvest (Feb-May) / Biomass removal and compaction treatments (May-July). Install weather instruments and soil water collection (July-Sept). Fence site (Nov) 2014 – Plant seedlings, initial tree measurements (March/April). First season tree measurements / 15 year measurements at Fall River LTSP Continue monitoring site conditions / Grad student projects – Second-year tree measurements (Oct). Report drafted by mid beyond Monitor site conditions, measure trees at year 5, 10, 15, etc.

17 Compaction OM Removal C0 – No compaction C1 - Moderate compaction OM0 – Bole only OM0 C0 Boles removed / No compaction OM0 C1 Boles removed / Moderate compaction OM1 - Boles and crowns removed OM1 C0 Boles & crowns removed / No compaction OM1 C1 Boles & crowns removed / Moderate compaction OM2 - Boles, crowns, forest floor removed OM2 C1 Boles, crowns & forest floor removed / Moderate compaction * F&G = + mid-rotation fertilization NARA LTSP Treatments A C B D/F * E/G *

18 NARA POST-TREATMENT AERIAL PHOTO Photo taken October 2013 – Post treatment – looking west across the north part of the study Total Tree Removal No Forest Floor Bole only Removal

19 NARA LTSP - TREATMENT LAYOUT Bole only / No comp Total Tree/ No comp Total Tree/ Compacted Bole only/ Compacted Forest Floor/ Comp Total Tree/ Compacted* Forest Floor/ Comp* * With mid-rotation fertilization

20 NARA POST-TREATMENT CONDITIONS Good separation. Pre-harvest range also shown A B C D/F E/G Pre-harvest range

21 INSTRUMENTATION - NARA LTSP 21 Standard Weather Stations (2) – Harvested area – Forest Every plot (28) + 4 in Forest: Soil moisture and temperature – 10, 20, 30, 100 cm 15 cm Air temperature and Relative Humidity

22 COLLABORATION - NARA LTSP 22 Jim Rivers / Matt Betts– OSU – Wildlife: Pollinators Jeff Hatten / Adrian Gallo – OSU – Soil Nutrients, Carbon/respiration Rob Harrison / Marcella Menegale – UW – Nutrient leaching Mike Barber / Mohammad Hasan– U. Utah (WSU) – Water issues / Microbial assessment Larger LTSP Network Looking for more…

23 PRELIMINARY RESULTS: SOIL TEMPERATURE

24 Fall River LTSP Weyerhaeuser's 15 year old Soil Productivity study in western Washington Summer 2009 Block 1 Block 2 Block 3 Block 4

25 FALL RIVER LTSP - OBJECTIVES Determine the impact of: Biomass removal Compaction and tillage Weed control (Fertilization) on stand productivity and soil and nutrient processes in a fertile Pacific Northwest Douglas-fir plantation

26 BIOMASS REMOVAL TREATMENTS Bole only (BO) Conventional harvest Total-tree plus all coarse woody debris (TT+) Total tree Bole only to 5-cm top

27 BIOMASS REMOVAL - TREE VOLUME AGE 10 Reference Treatment No significant difference

28 COMPACTION +/- TILLAGE TREATMENT 47% of area trafficked during shovel-yarding Aerial view “Non-compacted” Cable-Yarding “Compacted” Shovel-Yarding

29 COMPACTION/TILLAGE - TREE VOLUME Reference Treatment No significant difference

30 FALL RIVER LTSP - CONCLUSIONS At this productive, nutrient rich site very modest, if any, declines in tree growth were seen in high biomass removal vs standard practices. Compaction/Disturbance at the level we did had no negative effects on tree growth.

31 GENERAL LTSP - CONCLUSIONS Across the network of other LTSP sites generally we don’t see large losses in productivity from the experimental removal of residual biomass. Where fall-down has occurred it was on sites with low nutrient levels prior to harvest so those are potentially the most at risk.

32 End