Benefits and risks of using more  wood biomass for energy in 

California 

Drawing on ‘POTENTIAL POSITIVE AND NEGATIVE 

ENVIRONMENTAL IMPACTS OF INCREASED WOODY BIOMASS USE 

FOR CALIFORNIA

byWilliam Stewart, Robert Powers, Kathyrn McGown, Lindsay 

Chiono, Teresa Chuang

University of California, BerkeleyDownload draft at http://forestry.berkeley.edu/

Contract Number:  BOA‐99‐247‐R

Natural forests provide more social and Natural forests provide more social and  environmental benefits than agricultural or environmental benefits than agricultural or 

suburban landssuburban lands

•• Wildlife habitats, biodiversity, reduced Wildlife habitats, biodiversity, reduced  erosion, and Aesthetically pleasing vistaserosion, and Aesthetically pleasing vistas

•• Part of of CaliforniaPart of of California’’s commitment to s commitment to  renewablesrenewables

•• They are also more affected by natural They are also more affected by natural  disturbances disturbances ––

fires, insects, diseasesfires, insects, diseases

The status quo of US energy consumers also has various environmental risks

The Status Quo for US energy has various environmental risks

The Status Quo for US energy has various environmental risks

The Status Quo for US energy has various environmental risks

Land use sector Consumer sectorForest sector

Non-forest land use

Forest ecosystems

Bioenergy

Wood products

Fossil fuel energy

Substitute products

Economy-wide emissions with wood products

Economy-wide emissions if no wood products as substitutes

PhotosynthesisRespiration

Wood product emissions

Full cycle assessment of the 3 sectors  involved with forest biomass

Land use sector Consumer sectorForest sector

Non-forest land use

Forest ecosystems

Bioenergy

Wood products

Fossil fuel energy

Substitute products

Economy-wide emissions with wood products

Economy-wide emissions if no wood products as substitutes

PhotosynthesisRespiration

Wood product emissions

Full cycle assessment of the 3 sectors  involved with forest biomass

Land use sector Consumer sectorForest sector

Non-forest land use

Forest ecosystems

Bioenergy

Wood products

Fossil fuel energy

Substitute products

Economy-wide emissions with wood products

Economy-wide emissions if no wood products as substitutes

PhotosynthesisRespiration

Wood product emissions

Full cycle assessment of the 3 sectors  involved with forest biomass

Forest after a “No Cost/No Profit”Fuel Reduction Treatment

With THP exemption, BCAP, & a local energy plant

Collins Pine in Chester, CA - 25 years of wood power

Benefits             Risks      Benefits             Risks      •• Utilize decomposing Utilize decomposing 

biomass that releases CO2 biomass that releases CO2 

anywayanyway

•• Utilize collected postUtilize collected post‐‐

consumer biomass that consumer biomass that 

would have gone to landfillswould have gone to landfills

•• Provide market for Provide market for 

suppressed trees that suppressed trees that 

currently increase risk of loss currently increase risk of loss 

from fires, insects, disease, from fires, insects, disease, 

etc. etc. 

•• Decrease in long term soil Decrease in long term soil 

fertilityfertility

•• Soil erosion and stream Soil erosion and stream 

damage from vehiclesdamage from vehicles

•• Removal of an excessive Removal of an excessive 

fraction of the wildlife fraction of the wildlife 

habitats related to dead habitats related to dead 

and down woodand down wood

But what has been measured? But what has been measured? What can be measured? What can be measured?

Atmosphere (-47)

Live Biomass (- 16 +/- 45)

Dead Biomass

(+19 +/- 29)

Harvested Wood Products (45)

Fire (4) Fire (19)NPP (809) Resp.(h) (738)

Harvest (42) Harvest (3)

Logging Residues (45)

Fire & Insects (52)

Turnover (681)

Canadian Managed Forest Carbon Flux

Stinson 2011

Land Cover Changes in Three Forested  Regions in California in km2 from 88,360  km2

in 1973 to 2000

Forest cover ‐

2,844 km2

Recent wildfires + 1,461 km2

Grass/shrub cover + 1,325 km2

Developed area +    108 km2

•Wildfire areas will regenerate but possibly to shrubs or grass unless an active 

reforestation program is implemented. •Nearly all wildfire area in corporate forest land gets replanted

but families and 

government agencies often have investment constraints or other goals•Loss of forested area will also lead to decrease terrestrial carbon storage

Source: Sleeter (2010)

Star Fire –

Harvest/Regenerate  vs. Lawsuit/Delay

Star Fire –

Harvest/Regenerate  vs. Lawsuit/DelayAction and No Action create different habitats and 

different patterns of future fire risks

June 2008 Fire – Yuba River Canyon

A lot of California looks like thisThis severe fire burned up many spotted owl sitesThere is less green biomass and more black biomassAnd fire weather could get a lot worse

Sometimes they burn up and may or may not be harvested and replanted

Key Questions on how biomass harvesting Key Questions on how biomass harvesting  affects environmental attributes concern:affects environmental attributes concern:

• Forest Growth Rates – Shift resources to bigger trees• Soil and Water Erosion – Much better BMPs now

• Soil Fertility – N, not C, is the limiting nutrient

• Fire, insect and disease risks  ‐

Increase or decrease?

• Wildlife Habitats and Vegetation Diversity

– Diversity of the forest matrix (<25% intensive managed) 

– Home ranges of wildlife vs. temporal impact of projects

• Conclusion: We need more experiments to guide a forward  looking strategy

Logs Go In * Wood Products and Energy come out

Big gaps in areas with  local biomass energy  plants

*Mendocino/Sonoma*Siskiyou*West Central Sierra Nevada*Southern Sierra Nevada

Forests*Southern California

US Forests‐

2006 Annual Carbon Flux83% to products, 16% to energy, 1.5% to waste

50% to pulpmill energy, 50% to paper OR to pellets, panels, energy

Industrial, residential, commercial heat

Net growth after removals and mortality

Left in forest –(+/-) wildlife habitats(-) excess fuel/fire risk(-) CO2 emission from microbial respiration(-) impede tree regeneration(0) direct plant nutrient(+) maintain humus

Remember: The US imports around 30% of our wood and >50% of our energy

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-$0$

Wood and Energy Use Implications in Buildings

1

2

3

Wood in the Consumer Sector

USFS (2006) and forward looking estimates of post‐logtruck biomass

49

47

Post-consumer bioenergy and wood product storage is estimated with USFS (2006) estimates in CAR v3.x, DOE 1605b and other more modern standards

243

Land use sector Consumer sectorForest sector

Non-forest land use

Forest ecosystems

Bioenergy

Wood products

Fossil fuel energy

Substitute products

Economy-wide emissions with wood products

Economy-wide emissions if no wood products as substitutes

PhotosynthesisRespiration

Wood product emissions

Full cycle assessment of the 3 sectors  involved with forest biomass