Forests and Wood Products in Climate Change Mitigation

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Forests and Wood Products in Climate Change
Mitigation

• Lauri Valsta
• Department of Forest Economics
• Faculty of Forestry and Agriculture

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Competing Uses of Forest Carbon

• Store carbon into the forest ecosystems
• Use forest carbon for energy
• Use forest carbon for materials

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Combining Carbon Storage and Use for Energy and
Products

• Increasing forest storage (forest carbon sink)
  usually means reducing harvests
• Increasing harvests usually means reducing forest
  storage
• Harvests lead also to traditional economic
  returns
• To study them together, oneneeds to integrate 3
  factors

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Store Carbon into Forest Ecosystems

• Biomass in forests grows and growth depends on
• Stand density
• Stand age
• Stand structure
• Species composition
• Site quality
• Climatic conditions
• Flow into semi-permanent storage in forest soil
• Mainly in humid climates
• Forest carbon permanence
• Forest fires
• Forest pests

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Use Carbon for Energy and Products

• Three kinds of climatic impacts
• Release of carbon in forest operations
• Change in forest growth
• Avoided fossil emissions
• Economic impacts of forestry and forest products

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Climatic Impacts of Use for Energy and Products
1. Release of Carbon in Forest Operations

• Depend strongly on local conditions
• Harvesting emissions
• Emissions of the harvesting itself
• Embodied emissions of equipment
• Emissions of road construction and maintenance
• Forest management emissions
• Seedling production
• Silvicultural operations

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Climatic Impacts of Use Carbon for Energy and
Products 2. Change in Forest Growth

• Depends strongly on local conditions
• Partial cut
• Decomposition of harvest debris
• Increased growth due to increased growing space
• Clear cut
• Decomposition of harvest debris
• Loss of soil carbon
• Time path of regrowth

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Climatic Impacts of Use Carbon for Energy and
Products3. Avoided Fossil Emissions
(Substitution)

• Energy substitution rate depends on
• Energy efficiency of the wood energy chain
• Emissions of the substituted fuel chain
• Material substitution rate depends on
• Life cycle fossil emissions of wood products
• Life cycle fossil emissions of the substituted
  products
• Functionally equivalent units to be compared
• Products differ strongly
• Life cycle fossil emissions
• Transportation
• Manufacturing
• Demolition

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Climatic Balance of Carbon (Forest) Use

• Impact on
• Carbon use for forest storage mitigation
• Forest carbon growth rate
• Forest soil storage 0/
• Forest carbon permanence -/0
• Net impact /-
• Carbon use in energy and products
• Release of carbon in forest operations -
• Forest (re)growth (next slide)
• Substitution effects (carbon use benefits)
• Net impact /-
• We need to compute the net of the two above
  assessments and valuation over time

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Societal Valuation of the FutureInterest rate
affects the value of regrowth

• A low interest rate (societal time preference)
  makes the regrowth of forest highly valued (0.1
  case). Then, harvesting is beneficial as the loss
  of biomass (valued as 120 ton/ha) is largely
  compensated by the future growth (valued as 110
  ton/ha).
• A normal interest rate (here, 3 real) makes the
  regrowth less valued. Then harvesting is
  discouraged as the loss of biomass (valued as 7
  ton/ha) is not compensated by the future growth
  (valued as 1 ton/ha).

Harvest
Regrowth
Harvest
Regrowth
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Current Understanding of the Different Factors

• Carbon use for forest storage Slide
• Forest carbon growth rate A
• Forest soil storage B
• Forest carbon permanence C
• Net impact D
• Carbon use in energy and products
• Release of carbon in forest operations E
• Forest (re)growth (next slide) F
• Substitution effects (carbon use benefits) G
• Net impact H
• We need to compute the net of the two above
  assessments and valuation over time

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Current UnderstandingA Forest Carbon Growth Rate

• This is known rather well for managed forests for
  most areas of the world due to forest growth
  studies and biomass modeling
• Less well know for some species and sites in the
  developing countries
• For very old forests, the growth rates are less
  certain and significant uncertainties exist for
  all regions

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Current UnderstandingB Forest Soil Storage

• Compared to forest growth, not as well known
• However, overall levels rather well know for
  boreal and temperate forests
• For tropical forests, coverage is not as good but
  useful data exist
• Very long term development is more uncertain

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Current UnderstandingC Forest Carbon Permanence

• More difficult to assess as natural variation is
  large
• The problem of sampling rare events
• For Europe and North America, level of knowledge
  is generally good
• For other regions significant gaps in knowledge
  exist

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Current UnderstandingD Forest Carbon Net Impact

• A rather large amount of studies exist
• For Europe and North America, level of knowledge
  is generally good
• For other regions significant gaps in knowledge
  exist
• For rotations that are close to those in managed
  forests, impacts are rather well known. For
  significantly longer rotations, uncertainties are
  notable.

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Current UnderstandingE Release of Carbon in
Forest Operations

• For Europe and North America, level of knowledge
  is generally good
• For other regions significant gaps in knowledge
  exist, however useful data exist
• Three important factors are
• The need for constructing new roads for
  harvesting
• The amount and speed of release of logging
  residue biomass
• Soil degradation

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Current UnderstandingF Forest Regrowth

• For most regions, regrowth is well known due to
  general forest growth knowledge
• Time preference is usually neglected which is
  problematic because
• The society in general has a time preference due
  to increase of wealth and technological
  development
• Climate policy may well have to assign priorities
  to early impacts compared to impacts in the far
  future (say, more than 50-100 years into the
  future)
• Exceptions Schlamadinger and Marland 1999,
  Valsta 2007

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Current UnderstandingG Substitution Effects

• Energy substitution (bioenergy use)
• Consists of assessment of the
• Emissions in the bioenergy production chain
  generally well known
• Avoided emissions (emissions of the substituted
  fuel) methodological problems in choosing the
  alternative fuel average fuel or marginal fuel
  (often makes a big difference)
• Rather good selection of studies exist
• Product substitution (material use)
• Similarly consists of assessment of the
• Emissions of the production and use of wood
  products well know in developed countries, less
  known in other regions
• Avoided emissions (emissions of the production
  and use of alternative materials) well know for
  the main materials
• Important methodological questions the reference
  material must be functionally equivalent in
  amounts
• Construction of reference cases is tedious
• A rather large amount of studies exist, however

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Current UnderstandingH The Net Effects

• Energy substitution (bioenergy use)
• Studies exist for Europe and North America,
  Japan?, China?, Australia
• Variations in energy systems and forest
  conditions make generalization difficult
• Product substitution (material use)
• Studies exist for Europe and North America,
  Japan, China?, Australia?, New Zealand
• Variations in construction, technology and forest
  conditions make generalization difficult
• Overall net effects can be simplified into
  'substitution multipliers' for which relevant
  values can be established

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Current UnderstandingJ The Net Effects, Grand
Total

• Substitution multipliers need to be connected to
  impacts in forest ecosystems
• Some studies exist in Finland, Sweden, Norway and
  USA
• Many regions lack studies
• Only a few studies that explicitly account for
  the time paths and time valuation involved
• Amounts of existing studies (relative)
• 1. Forest carbon sequestration
• 2. Forest and wood product sequestration
• 2. substitution effects