Standard Operating Procedures - Vegetation Functional Traits Lab Metrics

KEY DETAILS

Principal Investigator
Dr. Nicola Stevens, Dr. Megha Ojha
Date
1 June 2025
Version
1.1.0
Programme
Rangelands Biodiversity Programme
Key partners
LCNR, Kew Gardens, University of Liverpool Contact email
nicolastvns@gmail.com

1. PREAMBLE

Natural State’s research methods and activities are detailed by a set of accepted Standard Operating Procedures (SOPs). These documents describe the steps involved in all Natural State research methodologies, from data collection to data processing and storage. Each SOP documents key methodological details for a specific data type. The objectives and background of the projects or surveys these methods are used for, features of the study area where these methods are applied, and details on survey and sampling designs for these methods may be found in survey Design Documents (DDs), which are available in the Related Documents section below or may be perused in the main NS Design Documents documentation page.

2. GLOSSARY

Natural State Glossary

3. METHODS OVERVIEW

A functional‐trait campaign standardizes measurement protocols to ensure data comparability and minimize observer bias. It targets representative sampling by focusing on species that drive ecosystem functions and using sufficient individuals and replicates to capture intraspecific variation. Sampling spans key habitat and environmental gradients and is integrated with established inventory plots for broader context. Traits are chosen for their clear mechanistic links to ecosystem processes, facilitating robust trait–environment analyses. Rigorous metadata recording, QR‐coded sample packaging, and standardized data capture ensure data quality and traceability. Finally, logistical efficiency and minimal ecosystem impact are achieved by confining destructive sampling to designated areas and maintaining controlled sample transport. Finally for this specific campaign we aim to introduce an extra layer of measurement to help tie remotely sensed data (drone and satellite) to on the ground field measurements, which is documented in the Aerial Cover Survey SOP. The Aerial Cover Survey should be completed before the Vegetation Functional Traits Field Survey as the aerial cover data is required to determine which species need to be sampled for functional traits. Samples collected using the Vegetation Functional Traits Field Survey should be processed in the lab using the Vegetation Functional Traits Lab Metrics SOP.

3.1 METHOD AIMS

Vegetation Functional Traits Lab Metrics are designed to collect:

  1. Leaf measurements
  2. Wet and dry mass of leaves
  3. Leaf spectroscopy data
  4. Leaf chemistry data
  5. Relative bark thickness
  6. Wood density

3.2 METHODOLOGICAL BACKGROUND

The methodologies outlined in this SOP adhere to three primary trait-handbook sources to ensure standardization and comparability worldwide: • Perez‑Harguindeguy, N., et al. (2016) Corrigendum to: New handbook for standardised measurement of plant functional traits worldwide. Australian Journal of Botany 64(8):715–716. • Cornelissen, J. H., et al. (2003) A handbook of protocols for standardised and easy measurement of plant functional traits worldwide. Australian Journal of Botany 51(4):335–380.

4. SAMPLING PREPARATION

The equipment mentioned in the list below needs to be gathered, checked and packed before sampling begins. If any sensors need to be configured prior to commencing sampling this will be documented below the equipment list. Before any field sampling, verify and pack all required items.

4.1 EQUIPMENT LIST

  • Tablet with S123 installed
  • QR code stickers
  • Leaf data stickers
  • Brown coin envelopes
  • Large brown paper bags
  • Paper towel (to dry samples for mass measurements)
  • Razor blades (clean samples if required)
  • Digital calipers (leaf thickness)
  • Beaker (wood density)
  • Needle and thread (wood density)
  • Handheld spectrometer (Joe from Kew)
  • Analytical balances (0.1 mg precision)
  • Scanner (300 dpi) (leaf area)
  • Fridge (store samples before wet measurements)
  • Drying oven (leaf dry mass)

4.2 DEVICE CONFIGURATION

  • The S123 app needs to be loaded onto the tablet and the Leaf FT Lab Labelling, Leaf FT Lab Metrics, Grass FT Lab Labelling, Grass FT Lab Metrics, Wood FT Lab Labelling, Wood FT Lab Metrics, and Bark FT Lab Metrics forms need to be loaded.

5. SAMPLING PROCEDURES

Samples will arrive from the lab in sealed ziploc bags and these should be left closed and stored in the fridge until samples are ready to be processed.

Below is an overview of the steps involved in the lab processing of leaf samples. In addition to this, bark thickness and wood density need to be measured.

5.1 Leaf functional trait lab metric collection

  1. Leaf prep: Collect three representative, healthy, sun-exposed leaves, including the petioles and stipules from each ziploc bag (1 ziploc bag represents 1 plant). For leaves that extend underground (e.g. grasses, sedges), cut the leaf from where chlorophyll is present (keep green, remove white tissue). For small-leaved species with multiple leaves or compound/pinnate leaf systems, count the number of leaves/leaflets in each sample and record this number on the leaf trait sticker. Remove soil or other matter from each leaf where required and place each leaf into a brown coin envelope labelled with a QR code and a leaf trait sticker. Scan the QR code of the ziploc bag that all three leaves came from and then scan the QR code of each coin envelope using the Leaf FT Lab Labelling S123 form. Pass leaf samples onto step 2. Pass remaining grass and forb samples on to protocol 5.2 below. Tree branch samples are now finished with.
  2. Leaf fresh mass: Carefully remove the leaf from the sample bag and gently blot dry with tissue paper to remove any surface water before measuring water-saturated fresh mass. Weigh each leaf (including blade, petiole and stipules where present) to the nearest 0.001 g and record the mass on the leaf trait sicker. Once weighed, cover the leaf with the moist paper towel and return it to the coin envelope.
  3. Leaf spectroscopy: Measure leaf level spectra in the lab using a FieldSpec® HandHeld 2™ Spectroradiometer. Spectroscopy should be done on only 1 of the 3 leaves collected per plant. Tick the ‘YES’ box for spectroscopy on the leaf trait sticker for this leaf and tick the ‘NO’ box for the remaining two leaves. On each leaf, take adaxial spectral readings at 3 different locations and avoid areas with prominent veins or irregularities. Copy the name of each spectral file onto the sticker. Perform white reference scans at regular intervals (every 10 minutes) to avoid instrument measurement drift and clean the lens regularly. Immediately check spectral curves for irregularities (sharp spikes/dips), redo the scans if required.
  4. Leaf area: Place leaf on a piece of clean white paper. Ensure that leaf blades are unfolded and that there is no overlap between leaflets, petioles or stipules. For leaves that are tightly folded down a midrib (e.g. some grasses), leave these folded for the scan and write ‘X 2’ on the piece of paper as a not to multiply the area by two when it is calculated. Place the QR code from the coin envelope next to the leaf, as well as a ruler or calibration grid. Scan the leaf and copy the name of the file onto the leaf trait sticker. Ensure that the leaf, QR code and ruler are clearly visible in the scanned image.
  5. Leaf thickness: Leaf thickness is the distance between the adaxial (upper) and abaxial (lower) leaf surfaces. For each leaf take three measurements using a pair of digital calipers at the midpoint of the lamina, avoiding major veins or the midrib. Ensure the instrument’s jaws lie flat against the leaf surfaces without compressing tissue.
  6. Dry leaf: Inside their paper envelopes, dry the leaves at 60 °C for 48-72 hours. Never exceed 60 °C to preserve tissue for subsequent nutrient analyses.
  7. Leaf dry mass: Weigh each leaf (including blade, petiole and stipules where present) to the nearest 0.001 g. Place leaves back inside their labeled paper envelopes.

  8. S123 data input: Take each brown coin envelope, scan the QR code into S123 and then enter all data into S123 using the Leaf FT Lab Metrics S123 form, being careful to not make mistakes.

  9. Leaf chemistry: Place leaves in their labelled brown coin envelopes into a large plastic tupperware full of silica for storage, then send leaves that were spectrometered for chemistry measurements.

5.2 Grass and forb plant functional trait lab metric collection

  1. Grass and forb stemminess: Use the remaining grass or forb sample (from which three leaves have already been removed) and meticulously separate stems from leaves. Place all stems into a brown paper bag with a QR code. Place all leaves into a separate brown paper bag with a QR code. Scan the QR code of the ziploc bag that samples came from and then scan the QR code of each paper bag using the Plant FT Lab Labelling S123 form.
  2. Dry samples: Dry leaves and stems in the oven at 60–70°C for 24-48 hours or until constant weight.
  3. Leaf and stem dry mass: Take each paper bag, scan the QR code into S123 and then enter the dry mass of the sample into S123 using the Plant FT Lab Metrics S123 form.

5.3 Tree bark and wood functional trait lab metric collection

  1. Bark thickness: Scan the QR code on the ziploc bag containing 10 twigs into the Bark FT Lab Metrics S123 form. Measure the stem thickness and bark thickness at the thickest end of each twig using a pair of digital calipers and record these in the Bark FT Lab Metrics S123 Form.
  2. Wood core volume: Scan the QR code on the ziploc bag containing the wood core into the Wood FT Lab Labelling S123 form. Place a QR code on a brown paper bag and scan this into S123. Measure the fresh volume of the wood. Place a beaker containing 100ml of water onto a scale. Record the mass of the beaker and water in S123. Insert a needle with a thread attached into the wood core. Gently lower the wood core into the beaker until fully submerged. Record the mass of the beaker containing the wood core into S123. Place the wood core into the labelled brown paper bag and dry the sample in the oven at 103 ± 2 °C until it reaches a constant weight (usually 48 hours). Once dry record the weight on the sticker.
  3. Wood core dry mass: Scan the QR code on the paper bag containing the dry wood core into the Wood FT Lab Metrics S123 form. Record the dry mass of the wood core in this S123 form.

6. POST PROCESSING

6.1 SAMPLE PROCESSING AND STORAGE

Leaves should stay in their storage container with silica in a cool dry place until the project PI advises that they are no longer needed.

6.2 DATA ENTRY AND UPLOADS

S123 forms need to be sent to the cloud as soon as possible.

7.1 DESIGN DOCUMENTS

7.2 OTHER RELEVANT SOPS

7.3 DATA ELEMENTS

Survey Design

Data Collection

Dashboard

8. REVISION AND VERSION HISTORY AND DESCRIPTION

v1.0.0 Initial SOP created in May 2025. v1.1.0 Modifications after in person meeting on first day of trait campaign in June 2025.