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Puu-0.3240 Wood Products: Properties & Performance. Wood and the environment 20 th January 2014. World population. Today. Sustainable development Megatrends Population growth Economic growth Climate change Carbon sequestration and carbon reservoirs

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Puu 0 3240 wood products properties performance

Puu-0.3240Wood Products: Properties & Performance

Wood and the environment

20th January 2014



Today
Today..

  • Sustainable development

  • Megatrends

    • Population growth

    • Economic growth

    • Climate change

  • Carbon sequestration and carbon reservoirs

  • The role of wood products in carbon storage

  • Embodied energy

  • Other benefits of wood


Sustainable development
Sustainable development

  • "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (from "The Brundtland Report", WCED, 1987: 43)

  • The “three pillars of sustainability”


Population growth
Population growth

  • The global population reached 7 billion on October 31, 2011

  • Now approaching 7,2 billion

  • Estimated to reach 9.20 billion by 2050

  • Growth in population during agricultural and industrial revolutions, better healthcare and vaccinations

  • Increasing expectations and aspirations

  • Can the Earth support this?


P R. Ehrlich et al. Nature 486, 68-73 (2012) doi:10.1038/nature11157


Limitations to economic growth
Limitations to economic growth

  • Is continued economic growth possible, without irreversible damage to the environment?

  • Many now think that it is not possible. See for instance “Growth isn’t possible: why we need a new economic direction”


Climate change
Climate change

  • Fact or fiction?

  • Most now agree that climate change is occurring and as a result of Humankind’s activities (there is still controversy)

  • In 2008, atmospheric carbon dioxide was 38% above pre-industrial revolution levels

  • Anthropogenic CO2, resulting from the burning of fossil fuels and deforestation


Anthropogenic co 2 emissions
Anthropogenic CO2 emissions

  • In 2008, 8.67 billion tonnes of carbon were released as a result of the burning of fossil fuels

  • This equates to the emission of 31.8 billion tonnes of CO2

  • In 1990 this figure was only 6.14 billion tonnes of fossil fuels

  • Only 57% of CO2 is removed by the biosphere and the oceans


Carbon sinks
Carbon “sinks”

  • Carbon sinks include the oceans, forests, agriculture and soils

  • Oceans account for ¼ of carbon “captured” from the atmosphere

  • Forests, particularly tropical forests sequester significant quantities of atmospheric carbon dioxide

  • A large amount of carbon is stored in soil. For example, around 80% of carbon in Canada’s boreal forests are stored in organic matter

  • Change in land use, deforestation and subsequent soil erosion is therefore a BIG problem


The role of wood in mitigating climate change
The role of wood in mitigating climate change

  • The carbon sink effect of forests

  • The carbon storage effect of wood products

  • Substitution for carbon-intensive materials

  • “It has been estimated that an annual 4% increase to 2010 in Europe’s wood consumption would sequester an additional 150 million tonnes of CO2 per year………” (CEI-Bois, Roadmap 2010, Executive Summary, 2004)


Carbon sequestration sink
Carbon sequestration (“sink”)

  • During growth, forests sequester atmospheric carbon CO2 through photosynthesis

  • This carbon is “locked-up” in the forest. It is estimated that 150 to 200 billion (thousand million) tonnes of CO2 is stored in Europe’s forests

  • The afforested area in Europe is growing, resulting is about 0.5 billion tonnes CO2 being additionally captured every year

  • As forests mature, less carbon is sequestered since natural decay leads to a return of the carbon to the atmosphere, but some is “bound” in the soil so that there is a net decrease in atmospheric carbon, but an “equilibrium” is established


Forest management harvesting
Forest management & harvesting

  • Harvesting wood removes carbon from the forest, and “rejuvenates” the ability to sequester carbon

  • Good forest management practices can help in the ensuring that the amount of carbon dioxide sequestered is maximised

  • And every cubic metre of wood “traps” around 0.9 tonnes of CO2

  • But once removed from the forest what then happens to the wood is important…..


What happens to harvested wood
What happens to harvested wood?

  • Energy (fuel wood)

    • Carbon dioxide returned to atmosphere v. quickly!

  • Energy & materials (“biorefinery”)

    • A longer route to return CO2 to the atmosphere

  • Materials

    • Pulp, paper and fiber products (CO2 returned quickly – 2 months)

    • Wood-based composites (CO2 stored for relatively long periods)

    • Sawnwood (CO2 stored for relatively long periods – 75 years )

    • Round wood (CO2 stored for relatively long periods)


Wood products
Wood products

  • If wood does not decay, it acts as a carbon storage “mechanism”. Carbon is only released back to the environment if it’s energy is released, e.g. by burning or decay (when decaying, part of the carbon is bound in organic matter in the soil)

  • What is the carbon content of wood?

    • Approximately 50% of dry wood is carbon

    • So every cubic meter of e.g. softwood contains about 250 kg carbon!

  • What is the net carbon content of wood products? i.e. after manufacture


Carbon storage potential
Carbon storage potential

  • In Europe around 220 million tonnes of CO2 is stored in wooden products

  • This figure is rising by about of 20 million tonnes annually

  • In Finland carbon stored in wood accounts for about 17.4 million tonnes (65 million tonnes CO2 equivalent)

  • Increasing by 0.4 million tonnes annually (i.e. about 1.5 million tonnes CO2,but equating to only 3% of CO2 emissions)


Production of wood products

Sawn wood

Wood-based

panels

Production of wood products

(Source: UNECE Timber Committee Forest Products Statistics)


Converted wood products
Converted wood products

  • Fuel wood: energy + CO2

  • Biorefinery: energy, materials + CO2

  • Wood products: materials + CO2

  • Energy is required for the conversion process (i.e. to manufacture the product)

  • This gives rise to the concept of “embodied energy”

  • Broadly speaking, embodied energy is related to the amount of processing, so e.g. it will be lower in sawn products than in e.g. MDF or paper



Embodied energy of sawnwood
Embodied energy of sawnwood

Figure 3. Embodied energy coefficients of softwood

timber based on the study of Mills A & B

compared with the results of other researchers (in MJ/kg).

(Source: Pullen, 2000)


Embodied energy of sawnwood1
Embodied energy of sawnwood

Approx. 7 MJ/kg

(Source: Puettmann & Wilson, 2005)


Embodied energy of particleboard
Embodied energy of particleboard

(Source: Wilson, 2010)


Embodied energy of particleboard1
Embodied energy of particleboard

  • Embodied energy of 10865 MJ/m3

  • Equates to around 15 MJ/kg (assuming density of 750 kg/m3)

(Source: Wilson, 2010)


Particleboard and further processing
Particleboard and further processing

Figure 4. Embodied energy coefficients of particle board and derivatives

compared with other researchers (MJ/kg).

(Source: Pullen, 2000)


Summary
Summary

  • Wood products have the potential to store carbon and at the same time promote carbon sequestration in the forest

  • This carbon storage potential needs to be “off-set” against the energy required to harvest and convert the tree to a usable product

  • The CO2 emissions relating to the embodied energy will of course relate to how the energy is produced in the first place (the forest industry is good in that residues are often used as the fuel source!)

  • Embodied energy increases with the number of processing steps, therefore, sawn solid wood has good characteristics as the embodied energy is relatively low

  • Moreover, much solid sawn wood is used in construction so the carbon will, potentially, be stored for many decades or even centuries, especially if it is re-used


Substitution
Substitution

  • On average, the substitution by wood of another building material reduces CO2 emissions to the atmosphere by an average of 1.1 tonnes CO2 . Add this to the 0.9 tonnes CO2 stored, saves a total of 2 tonnes CO2!

(Source: CEI-Bois; Tackle Climate Change)


Other points
Other points

(Source: CEI-Bois; Tackle Climate Change)

  • In use (in construction) wood results in lower CO2 emissions

  • Is a good thermal insulator, therefore leading to lower energy costs

  • Moderation of the interior climate (moisture buffering)

  • Other health and wellbeing benefits



Final thoughts reduce reuse recycle or else
Final thoughts: reduce, reuse, recycle….. Or else?

  • Clearly we cannot continue to consume at the rate we currently do, nor can the Earth meet the demands for an ever increasing global population with increasing aspirations

  • Technology can (maybe) provide some of the answers but not all

  • We must reduce our consumption, but how does this square with economic growth?

  • How do we use our resources? 95% of fossil reserves are burnt!


References and further information
References and further information

  • “Tackle Climate Change: Use wood”, CEI-Bois

  • “Growth isn’t possible: why we need a new economic direction”, New Economics Foundation

  • Wilson J.E. (2010). Life-Cycle Inventory of Particleboard in Terms of Resources, Emissions, Energy and Carbon. Wood and Fiber Science, 42, pp. 90–106

  • Laturi, J., Mikkola, J. & Uusivuori, J. 2008. Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050. Silva Fennica42(2): 307–324

  • Pullen, S. (2000) Estimating the Embodied Energy of Timber Building Products. Journal of the Institute of Wood Science, 15(3)

  • Puettmann M. E. and Wilson, J.B. (2005) Life-Cycle Analysis of Wood Products: Cradle-to-Gate LCI of Residential Wood Building Materials, Wood and Fiber Science, 37 18 – 29


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