How Does Carbon Yield Work in Plantation Forestry Projects?

Trees grow and sequester carbon, right? Here’s an explainer on how commercial plantation management practices can affect carbon yield.

It’s probably a bit of a no-brainer that when you thin, harvest and re-plant commercial trees, you’re going to have a different carbon storage outcome than a permanent planting. In this blog, we’re unpacking the impact that management events have on a plantation project’s modelled carbon yield. As always, these are general rules and indicative impacts, but every plantation’s context is different. To get specific insight on yield possibilities at your site, talk to our friendly team about your plans.

To keep things simple, we’re going to use the example of establishing a new plantation on a greenfield site, or what’s known as a Schedule 1 project under the plantation forestry method. If you need a little refresher on the different practices and schedules under the plantation method, and how carbon yield modelling works, here’s a couple of introductory blogs we’d recommend: 

• Plantation Forestry Carbon Projects 101
• The Beauty of Heatmaps (written about environmental planting projects, but a similar FullCAM model and the same general principles of carbon yield modelling apply to plantation projects too).

What you need to know to understand plantation carbon yield potential

There are a few pieces of info you’d want to be across (or can guesstimate) so that we can help you with an accurate indication of your plantation project’s yielding potential. FYI, for plantation projects, we need to factor in rotations across a 100 year period to model the correct yield in FullCAM. Don’t worry, this doesn’t mean you commit to a 100 year permanence period for your plantation – it’s just to get gross yield right in the first instance (known as your long-term project carbon stock). Here’s the list of plantation management details that it would be helpful to be across:

• Location: A map, mapping file, or the ability to locate your property geospatially is required.
• Hectares: An indication, even if rough, of the total area you’ll establish your plantation on.
• Species: You’ll either need to know what species you plan to plant or can suggest a few options to compare their yielding potential.
• Rotation: The period for which you plan to grow your trees prior to harvest.
• Site preparation: These are optional modelling choices, but it’s helpful to know whether you’d undertake a windrow and burn (piling debris into rows and burning it), or chopper rolling (mechanical) site preparation to prepare the site between rotations for planting your seedlings. 
• Planting date: The date on which you plan to complete planting your first, and subsequent, rotations.
• Fertiliser events: Optional again, but if you plan to fertilise your trees, it is helpful to know when it’s to be applied.
• Weed control events: Optional again, but if you plan to do any weed control on your trees, the date this is likely to be completed within each rotation. 
• Thinning events: This event is optional too, as it’s species and rotation dependent. However, if you’ll thin trees then have handy a general date within each rotation that this is likely to be completed, the % of forest to be removed and if any product recovery from the trees will take place (as pulpwood or sawlog products). 
• Clearfell harvest events: This one is implied by your rotation, but you’ll need to know the likely date when each clearfell harvest would be completed (per rotation). 

What are the impacts of each assumption?

• Location: FullCAM modelled yield differs site to site due to the varying topography, soils and climactic conditions in different parts of the country – so pinpointing your proposed plantation’s location will mean you get a more accurate yield result
• Hectares: The more hectares you can plant the more carbon you’ll sequester.
• Species: Different species can have quite different yielding results. Depending upon what’s viable in your region, it may be prudent to model some different options to weigh up carbon potential alongside the other practical and commercial implications of various trees.
• Rotation: As a general rule of thumb, the longer your trees grow, the more carbon they’ll store, with less harvest events where some carbon, and carbon sequestration potential, is always lost.  Again, rotation choice needs to be appropriate to your region, species, and practical and commercial realities – carbon is just one piece of the puzzle. Schedule 6 of the method provides default rotations for common plantation forestry species which can assist you to determine generic timeframes – check these out in our Plantation Guide.  It’s worth noting that no rotation can be longer than 60 years in duration, and as far as reasonably practicable, the periods between rotations are no more than 24 months apart. 
• Site preparation: Site preparation is often necessary and must form part of a project’s carbon abatement estimate if undertaken. As a general rule, site prep involves the release of carbon into the atmosphere so will have a slight negative affect on carbon yield, with windrow and burning likely to have the larger impact due to emissions released via burning.
• Planting date: This is the date from which the model will start to accrue sequestered carbon.
• Fertiliser events: The model allows one fertiliser event per rotation, and the use of fertiliser is modelled to improve tree growth by half a year – which will optimise your carbon yield. 
• Weed control events: The model allows one weed control event per rotation, and doing so will improve modelled tree growth by a year – which is even better for optimising your carbon yield.
• Thinning events: Thinning should be modelled as appropriate for your management regime, and its impact on carbon will differ from context to context. For instance, if thinned trees are retained for products, more carbon will also be retained in those products, and the remaining trees may grow more rapidly with less competition. However, the capacity for continued growth in stored carbon from thinned trees is lost and emissions will likely be released in the thin. 
• Clearfell harvest events: Clearfell events are modelled similarly to thinning events and have a similar, contextual carbon impact. There is usually a dip in net carbon sequestration, but with the re-planting of a new rotation, it is possible that over time you will continue to see net growth in carbon sequestration – particularly for long rotation plantations. For a visual representation of this, check out page 33 of the regulator’s Simple method guide. 

By understanding and weighing up the impact of these different management practices, you can then advise us how to model FullCAM carbon yield for your plantation. You’ll get a good sense of how much carbon you could sequester – and how many credits you could earn – across a project lifetime. 

Makes sense? Here’s some next steps: 

• Contact us to sense-check the eligibility and viability of your plans. We can provide a more detailed feasibility assessment and offer advice on the different carbon project developers in the market and their respective business models who can help to set up your project.
• Subscribe to our newsletters

Ready to find out more?

Explore our range of educational resources in our Carbon Farming Education Hub where we frequently publish educational articles, webinars, and guidebooks. 

When you’re ready to explore the feasibility of undertaking a carbon project on your property, email us at [email protected] or give us a bell at (08) 6835 1140 to be connected with one of our project facilitators.