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Basal diameter measures of stems (generally 20 cm above ground level) and tree height were recorded in July 2018. Basal measurements were largely below the first branch (D10–D20) or, if the branch were lower than 10 cm high, on all of the branches at ca. D20.

Biomass was calculated using two allometric equations. Allometry for estimates of AGB were based on Paul et al. 2016 and Navar et al. 2013.

References

Navar et al. 2013. Regional aboveground biomass equations for North American arid and semi-arid forests. Journal of Arid Environments 97, 127-135.

Paul et al. 2016. Testing the generality of total above-ground biomass allometry across plant functional types at the continental scale. Glob Chang Biol. 2016 Jun;22(6):2106-24. doi: 10.1111/gcb.13201.

Installations

Band dendrometers were installed on Mulga (Acacia) and understorey shrubs (Psydrax latifolia) in 2011. Half of the dendrometers were installed on 7 April 2011, and the remainder were installed on 20 July 2011. Maintenance and measurement of the dendrometers on P. latifolia have been abandoned. The dendrometers are constructed of a flexible measuring tape and a spring.

The original installation included a cable tie to hold the dendrometer together. These cable ties were found to have anchored the dendrometers to the tree in March 2012, and they had begun girdling some of the trees as the bark grew around the bands. The cable ties were removed and the bands reset at that time. Before removing the bands, it was noted that some of the dendrometers were installed onto the tree "backward" (see below).

We will refer to two ends of the tape: the start point and the free end. The value on the tape at free end was noted upon installation and confirmed or corrected on 15 August 2015. The start point is where the tape ends against the tree. The tape was then wrapped around the stem until the free end overlaps to obscure the start point of the tape. The free end is secured with a spring to a point midway around the tree, and the free end must be handled carefully to avoid accidentally removing the dendrometer from the tree before measurement.

Measurements

Measurements are made at the free end on the tape below. Trees are located by the GPS label Dend-Muxx, where xx is the tree number.

• Confirm the value of the free end (the end under the spring).

• Carefully move the spring out of the way to locate the position of the free end. Avoid excessively disturbing the spring to prevent the dendrometer from coming free of the tree.

• The value on the tape just below the free end is the measurement to be recorded.

• Care must be taken in determining the measurement because the values increase with increasing stem size in some dendrometers but decrease with increasing stem size in others (i.e., some dendrometers were installed "backward"). To avoid mistakes, check the tape for the direction in which the numbers are increasing.

• Note the status of the tree if dead, colonised by termites, etc.

The range of values on the tapes is more-or-less 0–100. Upon passing 100, values reset to 0 in most cases. The dendrometers that go past a reset point are also noted to facilitate quick checking of the new measurements.