Planting Trees to balance Construction Carbons

We often asked by Constructco2 users, can we offset by planting trees on site and if so how much carbon is ‘offset’? The response can be complicated – but that’s not a reason not to balance construction carbon emissions through increasing living carbon in trees and other living eco systems. 

Before diving in to the role of trees within managing construction CO2 – we need to understand current carbon footprint thinking – so take a look at this fairsnape blog post – Carbon Is Not The Enemy – on why we need to balance the Fugitive Carbon with Durable and Living Carbons 

Trees and Carbon

The answer is not at all straight forward and publications / papers / articles found on the internet do not agree. However, the amount of carbon stored by a tree depends on its size, and age: young trees will absorb carbon dioxide quickly while they are growing, but as a tree ages a steady state would eventually be reached. At this point the amount of carbon absorbed through photosynthesis is equal to that lost through respiration and decay.

Ecometrica study found a one tonne carbon tree locks up around 3.67 tonnes of carbon dioxide from the atmosphere

A tree can absorb as much as 24kg of carbon dioxide per year and could potential sequester 1 ton of carbon dioxide by the time it reaches 40 years old.

On average, each National Forest tree will sequester 79kg of carbon, equivalent to 290kg of carbon dioxide, over an 80 year period of growth.

A recent study carried out at Kielder Forest has calculated that the Forest’s 150 million trees lock up 82,000 tonnes of carbon* annually. This means that as a rough estimate each tree at Kielder is locking up 0.546 kg of carbon per year.

It is better to offset in forests rather than individual trees asm within the UK, forest soils contain around four times as much carbon as the trees.

CO2 is absorbed from the atmosphere by trees during their growth through photosynthesis. The carbon element of the CO2 absorbed remains locked into the timber until its End of Life. The sequestered carbon should though only be considered a benefit in the scope of (any) carbon assessment when the timber is sustainably sourced – certified by FSC, PEFC or equivalent. This is to ensure that any trees felled are being substituted with a minimum of the same number of trees planted and therefore not contributing to deforestation and not compromising the overall carbon- absorbing capacity of woodlands.

Understanding definitions. The language used when talking about carbon in trees and other eco systems is important. 

Biogenic carbon. The carbon sequestered in timber or other bio-based materials.If we are concerned with using trees to offset our construction carbon emissions then we need to address the tree’s sequestration and storage of CO2.

Sequestration The natural process removing (ie seizing) CO2 from the atmosphere and storing it within biological material.

Sink  A carbon ‘sink’ is where there is a net transfer of carbon from the atmosphere to the (tree/forest)  A forest only remains a sink while its carbon stock continues to increase.

Store Wood products are a store of carbon, as they themselves do not capture carbon dioxide from the atmosphere, but keep it locked up throughout their lifetime

 
The most important point is that offsetting – whether through tree planting or not – should not be the first consideration; reducing emissions should always be the main objective.
 
 

Perhaps value engineering to increase materials that have a high carbon store (eg timber) in lieu of materials that have a high embedded carbon footprint through processing (eg concrete) may prove a more viable carbon option.

Importance of locking carbon into long lived, circular economy based, timber products … 

When a tree dies the carbon that is stored in its biomass is either released to the atmosphere or added to the carbon in the soil through decomposition. The rate that carbon is released back to the atmosphere can be controlled by reducing the rate of decomposition, for example by using timber to create long-lived wood products. However, eventually most of the carbon sequestered by the tree will be returned to the atmosphere where each tonne of carbon will be converted to about 3.67 tonnes of carbon dioxide.

More than just Carbon

UK woodland, especially native species, in addition to providing the habitat for our incredible natural biodiversity, provide a wide range of “ecosystem services” such as the control and condition of water supplies, mitigation of surface water flooding, provision of shade, shelter, control of pollution.  Woodland plays a far greater role in the move to a low carbon economy than simple carbon sequestration by trees.

ConstructCO2 Guidance

  1. If planting (additional) trees on site obtain a carbon figure from the projects ecologist or landscape architect. (ConstructCO2 can arrange one for you). You cannot count the landscape design as offset for your construction emissions.
  2. A very rough figure for guidance, for each additional young tree planted on the project 1kg CO2 per month that the tree will be growing.
  3. Consider and promote the regenerative benefits of trees, which will be far greater than simply carbon offsets.
  4. If looking to offset your construction CO2 through tree planting offsets – use a certified organisation and ensure that the offset is an additional measure, and not counted elsewhere.
  5. Consider offsetting to schemes that protect, enhance soils and bring peat bogs and moss lands back into healthy, carbon sequestration eco systems. This can be a higher co2 sequestration than trees.
  6. Consider increasing project materials with a high carbon store – locking greater levels of carbon into the building through sustainability focused value engineering.

Tree Facts

  1. A single tree can absorb CO2 at a rate of 12kg per year.
  2. Trees act as natural pollution filters by absorbing pollutants through the stomates in leaf surfaces.
  3. Trees lower temperature by transpiring water and shading surfaces.
  4. Trees reduce heat sinks.
  5. Trees reduce erosion.
  6. An acre of trees absorbs enough CO2 over one year to equal the amount produced by driving a car 26,000 miles.
  7. Trees provide food and wildlife habitats.
  8. Planting trees remains one of the cheapest, most effective means of drawing excess CO2 from the atmosphere.
  9. Trees recharge ground water and sustain stream flow.
  10. One large tree strategically placed can replace 10 room-size air conditioners operating 20 hours per day.

Sources

“This Changes Everything” Paris Agreement and the Built Environment

That the Paris Agreement has come into force today, 4th November 2016, some four years early, now ratified by the requisite number of nations, is a huge milestone and speaks volumes for the global recognition and consensus to reduce carbon emissions.

cop21 article 2 draft

Back in December in Paris, the built environment was recognised as a major contributor to the carbon problem as well as having a major role to play in a low carbon sustainable future. (See How significant was the first Buildings Day at COP21?)

Now, then, is the time to review our approaches to taking carbon out of the built environment, through design, through the operation of buildings and in the manufacture and construction processes.

Through ConstructCO2 we know that up to 70% of construction carbons are travel and transport related, and much of this through diesel fuelled vehicles, further adding to our air quality problems and stretched health services. Construction transport impact must now be a primary target for sustainable construction.

In the UK, our most recent industry target is within Construction 2025 Vision – to reduce emissions by 50% by 2025. Consider however that this was written when the consensus for carbon reduction was based on a 2 degree target for temperature increase. We are now looking at 1.5 degree as the emerging consensus, and that changes everything.

construction-2025-headlines

There is a sense of urgency here, and as I explored and commented within FutuREstorative ‘we no longer have the luxury of being only less bad’ but need to be doing more good, and in doing so heal the future.

less-bad-more-good-chart

In 2015 the UK Green Construction Board noted that ‘reducing built environment carbon emissions (50% from 1990 levels by 2025) is now out of reach with current practice’, and as Namoi Klein wrote in This Changes Everything (2015) “There are no non-radical approaches left before us in addressing climate change’

But we do have approaches, tools and initiatives to ensure that the built environment can contribute to a 1.5 degree future, again as explored in FutuREstorative and illustrated here in this infographic:

carbon-image

As we celebrate the Paris Agreement coming into force, lets also take the opportunity to look forward and start working collaboratively within the built environment towards a 1.5 degree future. And in doing so,to address the other hugely important aspects of the Paris Agreement, adopt the Sustainable Development Goals.

Chart_of_UN_Sustainable_Development_Goals

The Price of Construction Carbons

screenshot.14
Distribution of Construction CO2

ConstructCO2 now allows the calculation of a ‘shadow’ carbon price for carbon emissions from the construction process. The default price is set at £29 / tonne, based on current available data as used by other organisations within their shadow carbon pricing exercises (1) However ConstructCO2 also allows for any user or project to set their own carbon price.

Carbon pricing is increasingly being used to drive carbon reductions, through internal costing arrangements, and as awareness or preparation for what many see as an inevitable carbon future regulations or taxation.

In the light of the Paris Agreement, the calls from businesses and activists to put a price on carbon are becoming louder. To keep global warming below the Paris target of 2 deg C, the UN Intergovernmental Panel on Climate Change says the world will need to get to zero net emissions urgently.

Construction processes are part of the climate change problem but a vital part of the solution , and by introducing an operating cost by factoring emissions into bottom-line calculations through carbon pricing will be part of the construction industry contribution to carbon reduction.

See FT article: Companies accelerate use of carbon pricing and for example the advertising group WPP, who use an internal price of £29 a tonne of CO2 when buying or refitting buildings to understand “the impact of future energy and carbon regulations on our business”.

Not knowing the construction industry carbon footprint is not acceptable.

Minimising and reducing carbon in construction has been a central plank of industry sustainability strategies for a good many years. It is therefore embarrassing for the industry, as Construction Manager reports, that we don’t still don’t have an industry handle on or indeed understand construction carbon figures.

An earlier Sustainability Strategy for Construction set a 2012 target of 15% reduction from the 2008 figure of 48T of CO2 / £million spend which should give us about 42 T / £m at 2012 with targets for further reductions by 2020 and 2050 in line with UK reduction targets.

Although … Peter Hansford “The strategy is to achieve a 50% cut in construction sector emissions from 1990 levels by 2025, and the GCB (Green Construction Board) is tasked with making it happen”

Indications are that, dispute a focus on sustainability, with just about every organisation in construction self-claiming to be sustainable,  construction emissions actually rose by 13% over the period 2008 – 2012.

As a major emitter of CO2, (when adding in transport and travel) the construction has a socially responsibility to address and reduce.

The fact that as an industry we don’t really know is down right unacceptable.

Our ConstructCO2 tool shows an average of 97.5kg / £k based on all construction types. As we gain more data (currently 300 projects) we can break this down into more meaningful targets, but since the first project on ConstructCO2 our benchmark has not fallen below 90kg/£K. (As an industry we should be below 40kg/£K)

When we founded ConstructCO2, we set out to keep it simple to record and used the strap line of Monitor, Understand and then Reduce.  Having monitored for a number of years we now understand the causes of construction carbon

Ashford School CCO2 A2 Poster

and can take steps to reduce through proactive planning.

Reducing Construction Carbon - Infographic


Why then, as industry we do not understand or monitor Construction CO2?

  • Cash in King, Carbon is Queen was a rallying call from Construction Advisor Paul Morrell – but very few rallied.
  • BREEAM hasn’t followed through – with just the requirement to record travel, transport and energy use, but not to reduce, monitor over time or collate. As an industry we have a mass of disparate spreadsheets across the country containing probably all the data we need.
  • Recording data at site level is deemed too time consuming, put into the too busy to do box by contractors, excepting of course the enlighten contractors using ConstructCO2 who see the benefits of doing so – or their clients are telling them to do so.
  • In the main, clients are not requiring projects to record and act on carbon emissions as a project key performance indicators.
  • Reducing carbon at site entails a collaborative approach from all on construction method, specification, procurement, planning, sub contractor management and so on. We simply don’t collaborate on reducing CO2.

Benefits of Monitoring CO2 (as reported by ConstructCO2 users)

  • Every kg of CO2 reduced equates to x£ not spent
  • Reducing CO2 from material and waste transport improves the local spend
  • Reducing mileage CO2 from personnel travel reduces driving time stress on operative & managers, improves productivity and time on site. Car sharing also reduces the fuel cost of operatives and managers.
  • Understanding the carbon issues enables more informed procurement, selection and logistics management

As Shaun McCarthy, Director of the Sustainability Supply Chain School said on twitter, its not Rocket Science,

Indications are that the GCB and WRAP UK will take up the mantle of managing data on construction carbons. Lets hope they talk to ConstructCO2, understand our lessons learnt and keep it simple but effective.

Reducing Construction Carbon – Project Planner / Infographic

The planning chart / infographic below was produced as part of the ConstructCO2 support tools to enable projects to reduce construction phase carbon emissions. It provides a visual check box for use at project planning stage as to what actions, initiatives and approaches will be taken to reduce carbon, and to achieve the project carbon target.

Further information on the ConstructCO2 site
Reducing Construction Carbon - Infographic

Managing Construction Carbons

Managing construction carbon is an essential part of successful project management.

If you are not already using constructco2, here is our latest update release for the ConstructCO2 carbon monitoring toolkit…

As part of the annual review of the ConstructCO2 toolkit’s conversion factors we have updated the Modes of Transport to match those published this year by DEFRA and the Carbon Trust. These updates ensure that we are in line with industry standards and reflect the emission improvements declared by DEFRA every year.

We are aware that many users are now using ConstructCO2 carbon footprint in connection with ISO 14001, Carbon Trust  Standard, ISO 9001 and other standards. You may be interested to know that we offer an independent audit and verification service to verify the accuracy of your data within ConstructCO2. Please do get in touch to discuss

We are also aware that some early adopters may not be fully using some of the more recent additions and improvements to the toolkit, therefore we will be running webinar refresher sessions in the autumn. More news and dates soon.

To assist in publicly demonstrating your commitment in measuring and reducing your projects carbon footprint we have developed:

Reducing Construction Carbon - InfographicA Reducing Carbon Action Planning Infographic to assist strategic and operational carbon reduction:

 

Project Carbon Performance Posters to communicate carbon progress and engagement with those on site:Ashford School CCO2 A2 Poster

 

 

 

 

 

and ConstructCO2 Banners, with QR codes allowing progress checks on performance:cco2 banner

We are very keen to hear your improvement suggestions to incorporate, or you have any queries please don’t hesitate to contact us.  Also if you are not currently using ConstructCO2 but would like a free trial just ask!

ConstructCO2 wins social media award at #Be2Awards

photo

Delighted that ConstructCO2 picked up a social media Be2Award  yesterday for the best ‘internet of things’, location-based or mobile app.

“Runner-up a few years back, ConstructCO2 has now moved on considerably. It has matured its monitoring of Construction Carbons at project, offices and company levels. It is now operating globally with projects in the UK, Europe, Americas, Far East and Australia.

However, the significant development this year is on the localism theme and the ability to monitor construction spend throughout the supply chain, based on project and supply chain locations, on set radials from the project.

Securing a Be2 means we successfully gained the recognition and endorsement of a substantial online community.”

The Be2Award trophy is made from recyled glass by Bottle Alley Glass in Yorkshire (websiteFacebook orTwitterwho sponsored the awards.

The best ‘internet of things’, location-based or mobile app was sponsored by Tekla