Robson Creek Rainforest Diameter, Height and Aboveground Woody Biomass Data 

This data contains stem diameter, height measurement and above ground living biomass calculations for an Australian tropical rainforest derived from a comprehensive ground survey of a large area from 2009 - present. Diameter and height measurements for stems ≥10cm diameter at breast height were sampled within 25 x 1 ha plots within the Robson Creek Rainforest site. Repeated measurements of individual trees have been conducted in the core hectare plot in 2010, 2015, 2019 and 2023. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging. This work was funded by the Terrestrial Ecosystem Research Network (TERN), an Australian Government National Collaborative Research Infrastructure Strategy (NCRIS) project. 

This dataset records tree diameter and height data used to calculate above-ground biomass across vegetation types in Australia. This data is important for mapping and monitoring changes in plant growth, carbon storage and terrestrial energy fluxes. 

Site information:
25 x 1 ha plots were established at the Robson Creek SuperSite in 2009. The vegetation in this plot is classified as complex mesophyll vine forest on granite and meta-sediment alluvium. Soil is classified as acidic, dystrophic, brown dermosol; medium, non-gravelly, clayey moderate.
Plot layout:
All 1-ha plots were divided into 25 subplots (20 m x 20 m ). Subplot numbering started in the south-west corner of each hectare and the order of subplot within each hectare is west to east, then east to west etc. Subplot numbering is continuous across the 25 ha plot, ending at 625 in the north-east corner of the 25 ha. Tree numbering is sequential within each hectare.
Tree survey:
All individual stems ≥ 10 cm diameter at breast height (1.3 m) were mapped within each 20 x 20 m subplot to an accuracy of 0.5 m. Each subplot is temporarily divided into 10 x 10 m quadrats to assist in mapping. Heights are recorded to the nearest 1 metre for each measured stem and are recorded as the length of the stem from ground to highest leaf, not height above ground level. Heights for easily visible and larger stems are measured using a Nikon laser range finder. The heights of all other stems are estimated by comparing to the measured stems. Stems ≥10 to ≤30 cm diameter at breast height (DBH) are marked with a tag attached to a wire encircling the stem. A line completely encircling the stem is painted at the point of measurement (POM). Repeated diameter and height measurements are conducted on all individual trees in the core hectare plot in 2010, 2015 and 2019. Height measurements were not taken in 2023, with height values from 2019 being used in biomass calculations
Biomass calculations:
Above-ground biomass was calculated for each stem >10 cm diameter at breast height using the allometric equation from Chave et al 2014: Chave, J., Réjou-Méchain, M., Búrquez, A., Chidumayo, E., Colgan, M.S., Delitti, W.B., Duque, A., Eid, T., Fearnside, P.M., Goodman, R.C., Henry, M., Martínez-Yrízar, A., Mugasha, W.A., Muller-Landau, H.C., Mencuccini, M., Nelson, B.W., Ngomanda, A., Nogueira, E.M., Ortiz-Malavassi, E., Pélissier, R., Ploton, P., Ryan, C.M., Saldarriaga, J.G. and Vieilledent, G. (2014), Improved allometric models to estimate the aboveground biomass of tropical trees. Glob Change Biol, 20: 3177-3190. https://doi.org/10.1111/gcb.12629. Wood density values were were taken from a database of species of northern Australia (CSIRO unpublished)