Warra Tall Eucalypt Coarse Woody Debris Data 

This data contains diameter, length volume, biomass and carbon measurements of all coarse woody debris pieces within the core 1 ha plot at the Warra Tall Eucalypt site in 2015. 

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. 

Coarse woody debris (CWD) is a fundamental component of forested ecosystems, providing habitat for organisms and play an important role in nutrient cycling and carbon storage. 

Coarse woody debris sampling:
Coarse woody debris (CWD) was sampled at the Warra Tall Eucalypt site in 2015. Sampling was split into two separate events, with different methods based on the diameter range of the CWD pieces (thin end diameter of CWD either > 40 cm or < 40 cm). For all pieces of coarse woody debris within size specifications (small end diameter > 40 cm, length > 1.0 m) within the Core 1 ha plot were measured. The 40 cm small-end diameter threshold was based on the work of Sohn et al. (2013) in similar wet E. obliqua forests in the Warra Tall environment. The diameter of the vertical and horizontal axis of both the large and small ends of each piece was measured using a retractable carpenters tape. The small end was set at the 40 cm diameter threshold and any log sections of smaller diameter beyond this 40 cm cut-off point were not measured. The length of the log section between the large and small diameter measurement points was measured using a tape and assigned a decay class based on the decay classification described in Grove et al. (2009). Where necessary, logs were divided into two or more sections (each with separate diameter and length measurements) such that each log section was a homogenous decay class. Logs were also divided into separate sections at each point of bifurcation. The location of each end of each log (or log section) was measured as a perpendicular distance to the nearest boundary of the 20 x 20 m sub-plot in which that log section occurred. These x-y distances to the sub-plot boundary were then converted to the x – y co-ordinates of the 1 ha plot. Where possible the taxon of the tree species generating the log was determined.
All pieces of coarse woody debris < 40 cm diameter (at point of intersection with transect) that were intersected by transects were measured. Four, 50-metre transects were laid-out within the Core 1 ha plot using a measuring tape. The start and end points of the transects are given in the x-y co-ordinate system of the 1 ha plot with (0, 0) corresponding to the SW corner of the plot. The x co-ordinates run east-west and y co-ordinates run north-south. Transect 1 commenced at point (0, 20) and ended at (50, 20). Transect 2 commenced at point (80, 0) and ended at (80, 50). Transect 3 commenced at point (100, 80) and ended at (50, 80). Transect 4 commenced at point (20, 100) and ended at (20, 50). The diameter of the CWD piece at the point of intersection by transect was measured in one of two ways: a diameter tape for suspended CWD, or measurement of the cross-sectional diameter of the vertical and horizontal axes using a retractable builders measuring tape. Each piece of CWD intersected by transects was assigned a decay class based on the decay classification described in Grove et al. (2009); was attributed as being either a log or branch and where, possible, the taxon of the parent tree species was identified.
Calculation of coarse woody debris volume, biomass and carbon
For the CWD pieces > 40 cm diameter: The vertical and horizontal axis diameter measurements of each end of each log or log section were converted to a simple average diameter. The volume of the log or log section was calculated using Smalian’s formula: Volume = length * ((Diameter thick end + Diameter thin end )/2). Biomass was calculated as the product of volume and wood density. The wood density was determined by the assigned decay class of the log using values for E. obliqua given in Grove et al. (2009). The weight of carbon in the log was calculated as the product of the log biomass and the carbon concentration of the log (assumed to be 50%).
For the CWD pieces < 40 cm diameter: The contribution to total volume per hectare made by each piece of CWD was estimated using the formula developed by van Wagner (1968): volume = Dia^2 * 3.1415^2 /8 * L Where: L is the horizontal transect length (after correcting for average slope of each 50 m transect) and Dia is the diameter of the piece of CWD. Biomass was calculated as the product of volume and wood density. The wood density was determined by the assigned decay class of the log using values for E. obliqua given in Grove et al. (2009). The weight of carbon in the log was calculated as the product of the log biomass and the carbon concentration of the log (assumed to be 50%).