🌿 Mangrove Tree Growth Survey

This guide covers how we collect mangrove growth data in the field, how plots fit into the workflow, and how your notes map to what the backend expects for TREE_GROWTH.

How plots work in MariMap

• A Site is the broader area you manage (e.g., “East Lagoon Mangrove”).
• A Plot is a repeatable area or transect segment inside the site where you measure trees over time.
• You can draw a plot boundary (polygon) or use a line/area you already track. Each plot has:
  • external_id (your code, e.g., CRS-TEST-250509-PLOT1)
  • Optional label (e.g., “Plot A” / “Transect 1”)
  • Optional notes
  • Optional geojson (Feature with geometry)

When you create a TREE_GROWTH survey, you attach one or more plots. Each attached plot contains one or more observations for trees measured that day.

Stable plot geometry is key: consistent boundaries make year‑over‑year change meaningful.

Before you go to the field

• Prepare plots for your site (draw geometry or confirm existing).
• Make a survey plan: which plots to visit, which species are expected, and any access constraints (tide windows).
• Gear checklist
  • Diameter tape or caliper (DBH)
  • Height pole / hypsometer (or a consistent height estimation method)
  • Measuring tape, flagging
  • Waterproof notebook or digital data sheet
  • Species ID references (field guide or app)
• Protocol: decide your DBH height standard (typically 1.3 m above ground) and handling of buttresses/irregular stems.

In the field — simple flow

1. Walk to the plot; confirm boundary or transect section.
2. For each species group you encounter:
   • Record species (taxonomy ID if known; otherwise write the scientific/common name to resolve later).
   • Measure DBH (cm) and height (m) for representative individuals.
   • Record count of individuals covered by this observation.
   • Score health (e.g., HEALTHY, STRESSED, DEAD) and add notes if useful.
3. Keep consistent method: same DBH location, same height estimation approach.
4. Add quick context notes (tide, weather, disturbances).

If trees have irregular stems or buttresses at 1.3 m, follow your protocol (e.g., measure at a fixed offset above the buttress) and note it.

After the field — data entry

1. Create a survey (type: TREE_GROWTH) for the site/date.
2. Attach plots you visited.
3. For each attached plot, add observations:
   • species_id (taxonomy ID once resolved)
   • dbh_cm (float)
   • height_m (float)
   • count (int)
   • health (enum)
   • notes (optional)

MariMap will compute biomass/carbon where available (based on species/allometry in your backend).

Data model mapping (what your entries become)

• Survey → SurveyCreate with type: TREE_GROWTH
• Attached plots → SurveyTreeGrowthPlotCreate items under data.plots[]
• Observations → SurveyTreeGrowthObservationCreate inside each plot

At read time, you’ll see resolved species and optionally biomass/carbon:

• SurveyTreeGrowthDataRead → plots[]
• Each plot → survey_tree_growth_observations[]
• Each observation → species, dbh_cm, height_m, count, health, biomass_kg, carbon_kg

Quality tips

• Use consistent plots and repeat dates (e.g., same month each year).
• If you change protocol, note it in the survey journal.
• Outliers: double‑check extreme DBH/height values before saving.

Quick checklist

• Plots defined for the site
• Gear ready (DBH tape, height pole, etc.)
• Roles clear (who measures, who records)
• Survey created and plots attached
• Observations entered and reviewed