Field Measurement Approach (FMA)
If you have 100 hectares or more of post-1989 forest registered in the ETS, you can’t use lookup tables — you must use the Field Measurement Approach (FMA) to calculate your forest’s carbon stocks.
Who Must Use FMA?
Mandatory For:
- Post-1989 forest land 100 hectares or more registered in the ETS
- Permanent Forest Sink Initiative (PFSI) participants (covenant requires it)
- Participants who choose FMA over lookup tables
Optional For:
- Forests under 100 hectares (can choose FMA if preferred)
- Those wanting more accurate, site-specific carbon measurement
How FMA Works
The Concept
Instead of using pre-calculated lookup tables based on forest type and region, FMA measures your actual forest to create participant-specific carbon tables.
This means:
- Your carbon stock is based on real measurements
- Tables are tailored to your forest
- More accurate than generic tables
- Higher administrative burden
The Process
- MPI provides sample plot locations — they determine where you must measure
- You establish permanent plots — physical plots in your forest
- You collect tree data — diameter, height, species, etc.
- Data is submitted to MPI — they process it
- You receive participant-specific tables — used for emissions returns
Sample Plot Requirements
Number of Plots
The number of plots depends on your forest area:
| Forest Area | Minimum Plots |
|---|---|
| 100 hectares | ~30 plots |
| 200 hectares | ~40 plots |
| 500 hectares | ~60 plots |
| 1,000+ hectares | Proportionally more |
The exact number is determined by MPI based on statistical requirements.
What’s Measured in Each Plot
At each permanent sample plot, you record:
- Tree count — number of trees
- Diameter at breast height (DBH) — for each tree
- Tree height — sample trees
- Species — identification
- Plot location — GPS coordinates
- Site factors — slope, aspect, etc.
Measurement Frequency
Mandatory Emissions Return Periods
A forest survey (all plots) must be measured once per mandatory emissions return period.
Currently, this is expected to be every 5 years ongoing, though:
- You can file more frequently if desired
- Periods may change with policy
- The 2023-2025 period had special rules
Recent Adjustments
Cabinet approved adjustments to reduce costs for participants during the shortened 2023-2025 reporting period, effective March 2025.
Costs
Who Pays What
MPI covers:
- Administering the FMA scheme
- Processing submitted data
- Generating participant-specific tables
You pay:
- Establishing permanent sample plots
- Conducting field measurements
- Consultant/inventory crew costs
- Data submission
Typical Costs
Costs vary significantly based on:
- Forest area and number of plots
- Terrain difficulty
- Access requirements
- Distance from service providers
Indicative range: $5,000-50,000+ per measurement round, depending on scale and complexity.
Cost vs Benefit
For most forests meeting FMA requirements, the additional carbon discovered through accurate measurement exceeds the cost of measurement.
Generic lookup tables are conservative. Site-specific measurement often reveals higher carbon stocks than tables would estimate — sometimes significantly higher.
The FMA Standard
MPI publishes the Field Measurement Approach Standard, which specifies:
- Plot allocation methodology
- Establishment requirements
- Data collection protocols
- Measurement standards
- Submission requirements
- Quality assurance
You must follow this standard precisely. Non-compliant measurements won’t be accepted.
Working with Professionals
Who to Engage
Most participants engage:
- Forest inventory providers — specialists in tree measurement
- Forestry consultants — project management and advice
- Registered cadastral surveyors — for precise plot location
What They Do
A typical engagement includes:
- Planning the measurement campaign
- Locating plots in the field
- Establishing permanent plot markers
- Collecting all required data
- Quality checking measurements
- Submitting data to MPI
- Liaising with MPI on any queries
Appointing a Representative
You can appoint a representative to manage ETS tasks on your behalf, including FMA obligations. This is common for landowners without forestry expertise.
Permanent Plots
Establishment
Permanent sample plots must be:
- Precisely located (GPS)
- Permanently marked
- Consistent across measurements
- Protected from disturbance
Ongoing Requirements
You must:
- Maintain plot markers
- Re-measure the same plots each period
- Record any disturbance or changes
- Report if plots are damaged
Plot Damage
If plots are damaged (e.g., by harvesting, storms):
- Notify MPI
- Document the damage
- Follow MPI guidance on replacement
FMA vs Lookup Tables
| Aspect | Lookup Tables | FMA |
|---|---|---|
| Accuracy | Generic, conservative | Site-specific, accurate |
| Effort | Minimal | Significant |
| Cost | Low | Higher |
| Flexibility | None | Reflects actual forest |
| Mandatory | <100 ha | ≥100 ha |
| Carbon outcome | Often underestimates | Usually higher |
Technology and Tools
PlotSafe
PlotSafe is a data collection guide and tool for ETS FMA measurements. It provides:
- Standardised data collection
- Field data entry
- Quality checking
- Export for submission
GPS and GIS
Precise location is essential:
- Survey-grade GPS recommended
- GIS for mapping and planning
- Integration with MPI systems
Data Submission
Data must be submitted:
- In prescribed format
- Through MPI’s systems
- Within required timeframes
- With quality declarations
Common Issues
Plot Location Challenges
- Dense forest makes access difficult
- Steep terrain increases costs
- Remote areas require more logistics
- GPS accuracy affected by canopy
Measurement Variability
- Different crews may measure differently
- Training and calibration important
- Quality assurance protocols essential
Timing
- Seasonal constraints (weather, access)
- Coordinating with MPI timelines
- Allowing time for data processing
Cost Management
Economies of Scale
- Larger forests have lower per-hectare costs
- Neighbouring participants can share mobilisation
- Multi-year contracts can reduce unit costs
Efficiency
- Good planning reduces field time
- Technology improves productivity
- Experienced crews work faster
Value Focus
Remember: the goal isn’t to minimise measurement cost — it’s to maximise accurate carbon recognition. Cheap measurement that misses carbon is false economy.
Practical Tips
- Engage early — don’t leave measurement to the last minute
- Choose experienced providers — forestry inventory is specialised
- Plan for access — discuss logistics upfront
- Maintain records — document everything
- Protect plots — they’re long-term assets
- Ask questions — MPI can provide guidance
- Budget appropriately — quality measurement pays for itself
Key Takeaways
- 100+ hectares means mandatory FMA — no choice but to measure
- Site-specific data usually beats tables — expect more carbon
- Professional help is essential — specialised work
- Costs are significant but worthwhile — measurement pays for itself
- Permanent plots are long-term commitments — protect and maintain them
- Follow the standard precisely — non-compliant data won’t be accepted