The PeatPic project: Predicting plot-scale green leaf phenology across peatlands
Data files
Oct 13, 2025 version files 1.17 MB
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Davidson_DOYPeakGreenness.xlsx
39.31 KB
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Davidson_RawGreenness.xlsx
1.12 MB
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README.md
13.53 KB
Abstract
This dataset comprises standardized plot-scale photographs and associated metadata collected from 42 peatland research sites during the 2021 and 2022 growing seasons. Using the PeatPic protocol, participants photographed dominant vegetation communities weekly to bi-weekly from pre-growth through senescence, capturing seasonal dynamics across bog, fen, and swamp ecosystems. Metadata includes vegetation type, microform, site characteristics, and disturbance history. RGB imagery was analyzed using the Phenopix R package to derive a greenness index, and seasonal trajectories were modeled using a Gaussian function to estimate the timing and magnitude of peak greenness. These data support cross-site comparisons of peatland green leaf phenology (GLP) and facilitate broader investigations into vegetation responses to climate and disturbance.
Dataset DOI: 10.5061/dryad.cz8w9gjgp
Description of the data and file structure
Between 2021 and 2022, researchers and volunteers from the peatland research community collected standardized, plot-scale photographs (0.036–1 m²) of dominant vegetation at various peatland sites using the PeatPic protocol. Each site included 4–12 plots that were either permanent monitoring points or temporarily marked areas. Photos were taken weekly or bi-weekly from directly above the vegetation throughout the growing season, under consistent lighting conditions, using a single camera type per site.
Alongside each photo, participants recorded key environmental details such as peatland type (bog, fen, swamp), vegetation community (e.g., feather moss-, Sphagnum-, graminoid- or shrub-dominated), microform (hummock, lawn, hollow), tree cover, permafrost presence, and disturbance signs.
The photographs were analyzed in R v2.4 using the Phenopix (Fillicetti et al. 2016) package to calculate a greenness index (a proxy for plant growth) and to model seasonal vegetation dynamics. Gaussian models were fitted to determine the timing and peak of greenness (growing season progression), with adjustments made to align data from northern and southern hemispheres.
Files and variables
File: Davidson_DOYPeakGreenness.xlsx
Description: Day of Year (DOY) at peak greenness and associated variables for 27 peatland sites
Variables
| Variable | Description |
|---|---|
| Plot ID | Unique ID for each plot (designated by Site PI) |
| Year | Year in which photos were collected |
| Site | Site name |
| Location | Country where study site is located |
| Camera or Phone | Whether the photograph was collected using a smartphone or camera |
| Peatland type | Whether the peatland was a bog, fen or swamp |
| Microform | Whether the plot was located on a hummock, hollow or lawn |
| Vegetation type | Whether the plot was dominated by graminoid, Sphagnum, feathermoss or shrub |
| Disturbance | Whether there was a disturbance present (Y/N) |
| Disturbance type | Details on the type of disturbance |
| Permafrost present | Whether the site was underlain by permafrost (Y/N) |
| Tree cover present | Whether the site has any tree cover or was open (Y/N) |
| Plot type | What type of plot - quadrat, flux collar, flagged |
| Plot area (cm2) | Area of plot in cm2 |
| Plot shape | Whether the plot was circular or square |
| Plot manipulation | Whether the plot had any manipulation (Y/N) |
| Manipulation.type | Details on the manipulation |
| Latitude | Coordinates of study site |
| Longitude | Coordinates of study site |
| Hemisphere | Whether site was located in Northern or Southern Hemisphere |
| Lat band | Whether the site is located in the Arctic, Boreal or Temperate region |
| Day of Year at Peak Greenness | The day of year when the plot hit it's maximum or peak greenness |
| DOY at Peak Greenness Std Error | Standard error of above |
| N/A | Data not available |
File: Davidson_RawGreenness.xlsx
Description: Greenness data and associated plot variables for 27 peatland sites
Variables
| Variable | Description |
|---|---|
| Site | Site name |
| Location | Country where study site is located |
| Camera or phone | Whether the photograph was collected using a smartphone or camera |
| Peatland type | Whether the peatland was a bog, fen or swamp |
| Plot ID | Unique ID for each plot (designated by Site PI) |
| Microform | Whether the plot was located on a hummock, hollow or lawn |
| Vegetation type | Whether the plot was dominated by graminoid, Sphagnum, feathermoss or shrub |
| Disturbance | Whether there was a disturbance present (Y/N) |
| Disturbance type | Details on the type of disturbance |
| Permafrost present | Whether the site was underlain by permafrost (Y/N) |
| Tree cover present | Whether the site has any tree cover or was open (Y/N) |
| Plot type | What type of plot - quadrat, flux collar, flagged |
| Plot area (cm2) | Area of plot in cm2 |
| Plot shape | Whether the plot was circular or square |
| Plot manipulation | Whether the plot had any manipulation (Y/N) |
| Manipulation type | Details on the manipulation |
| Year | Year in which photos were collected |
| DOY | Day of year when photograph was taken |
| r.av | Average digital number (DN) values for the red channels from a region of interest (ROI) in an image. |
| g.av | Average digital number (DN) values for the green channels from a region of interest (ROI) in an image. |
| b.av | Average digital number (DN) values for the blue channels from a region of interest (ROI) in an image. |
| r.sd | Standard deviation of the DN values for the red channel in the ROI—used to assess variability or noise. |
| g.sd | Standard deviation of the DN values for the green channel in the ROI—used to assess variability or noise. |
| b.sd | Standard deviation of the DN values for the blue channel in the ROI—used to assess variability or noise. |
| bri.av | Average brightness, usually calculated as the average of R, G, and B values: bri.av - r + g + b / 3 |
| bri.sd | Standard deviation of brightness |
| gi.av | Green chromatic coordinate (GCC), often calculated as: g/r+g+b. A key index for phenology, correlating well with vegetation "greenness". |
| gi.sd | Standard deviation of gi.av |
| gei.av | Green-Excess index, often calculated as = 2g−r−b. Measures the excess of green over red and blue, often used for detecting vegetation. |
| gei.sd | Standard deviation of Green-Excess Index |
| ri.av | Red chromatic coordinate (GCC), often calculated as: r/r+g+b. |
| ri.sd | Standard deviation of ri.av |
| bi.av | Blue chromatic coordinate (GCC), often calculated as: b/r+g+b. |
| bi.sd | Standard deviation of bi.av |
| Latitude | Coordinate of study site |
| Longitude | Coordinate of study site |
| Hemisphere | Whether site was located in Northern or Southern Hemisphere |
| Lat band | Whether the site is located in the Arctic, Boreal or Temperate region |
| DOY adjusted | Day of year adjusted for Southern Hemisphere sites to match Northern Hemisphere by adding 182.5 to any DOY less than 182.5 and by subtracting 182.5 from any DOY greater than 182.5 |
| N/A | Data was not available |
Access information
Data was derived from the following source:
Data was derived from standardized community-collected peatland photographs taken between 2021 and 2022 to monitor seasonal vegetation greenness and growth patterns across global peatland sites.
Using the standardized PeatPic protocol, participants collected nadir-view photographs (0.036–1 m² plots) of dominant vegetation communities at 27 peatland research sites. Photographs were taken weekly to bi-weekly throughout the growing season and into autumn, under consistent lighting (auto white balance, overcast or clear skies, no shadows). Plots (4–12 per site) were either permanent or temporarily marked. Each site used a single camera or phone model. Metadata collected for each plot included peatland type, dominant vegetation group, microform type, experimental treatments, tree cover, permafrost presence, and disturbance history.
RGB images were analysed using the Phenopix R package (v2.4.4; Filippa et al. 2016). Greenness Index was calculated as GDN / (RDN + GDN + BDN), omitting images with snow or standing water. Regions of interest were delineated using DrawROI and greenness indices extracted per pixel with Extract VIs. A Gaussian model was fitted to greenness values by day-of-year (DOY) for each plot-year (n = 319), with parameters describing peak greenness (a), DOY at peak (b), and seasonal progression (c). Models with p > 0.05 were excluded (n = 96). To align hemispheric seasons, southern hemisphere DOYs were offset by ±182.5 days as appropriate.