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Tree demography surveys at two sites in the southern Mount Lofty Ranges – a monitoring pilot study.

dataset
posted on 08.12.2020, 04:55 by Greg GuerinGreg Guerin, Jacob MillsJacob Mills

The data consist of pilot tree demography surveys at two sites, which aimed to assess feasibility of sampling the distribution of size classes and tree status as a survey and baseline for monitoring. The study comparatively assessed the quality of information gathered from modules of the Bushland Condition Monitoring (BCM) method (Croft et al. 2009) and a plot-based method modified from AusPlots Forests (Wood et al. 2015).


We collected tree data at two TREND sites located at Horsnell Gully (HOR-A) and Montacute (MON-A) in the Adelaide Hills. At each site, tree demography data were collected using both the BCM method, which is based on sampling the 10 nearest trees to a central point, and a modified version of the AusPlots Forests survey protocol in which all trees within 30 x 30 m plots (overlaid with existing species composition plots of the same size) were sampled. Tree measurements included spatial location (GPS), DBH (Diameter at Breast Height) or GBH (Girth at Breast Height), basal area (derived collectively from DBH), % canopy dieback, number of hollows, number of mistletoes, tree height, and trunk condition/status.


For the BCM method, measurements were taken from the 10 nearest trees in a circle around the SW corner peg of the plot. Distance from each tree to the SW peg was measured with a tape and a compass bearing was taken from the peg to each tree. Growth form was assessed as mallee eucalypt, other eucalypt, or other tree. Each tree was assessed as dead or alive and for multi-stemmed trees, the number of trunks was recorded and each assessed as dead or alive. GBH was measured in centimetres with a tape at a height of 1.35 m on the largest stem. DBH was measured in centimetres (cm) with a diameter-adjusted tape at 1.3 m length from the ground for every stem for comparison. Percentage foliage dieback was visually estimated. Hollow presence was counted as yes/no (including cracks) and mistletoes were counted.


For the modified AusPlots Forests method, existing 30 x 30 m plots orientated NS-EW were used. Plots were marked for survey by running 30 m tapes around the NS-EW boundaries, guided by compass bearings from the permanent plot marker located in the SW corner. Measurements were taken from individuals of each tree species that occurred within the plot where DBH was 10 cm or more. Each tree was GPS marked (WGS84) and permanently tagged with sequential numbers at ~1.6 m above the ground. Tree height was measured with a Vertex Hypsometer. All trunks were assessed as dead or alive and percentage (%) foliage dieback was visually estimated. The number of mistletoe clumps was counted and DBH was measured with diameter tape at 1.3 m above ground for every stem. Basal area (area of stem at breast height per area in cm2/Ha) was later calculated from DBH. A nested 10 x 10 m subplot in the SW corner was used to score the number of tree seedlings (defined as <2 m tall and DBH <2 cm) and saplings (defined as >2 m tall and/or DBH >2 cm but <10 cm DBH) for all tree species.


The data were reported in Guerin (2017).



References:


Croft, S.J., Milne, T.I. and Pedler, J.A. (2009). ‘Bushland Condition Monitoring Manual: Murray Darling Basin, South Australia’. Nature Conservation Society of South Australia, Adelaide, South Australia.


Guerin, G.R. (2017) Monitoring diversity and tree demography in vegetation communities of the Mount Lofty – Flinders Ranges. The South Australian Naturalist. 91, 56–67.


Wood, S.W., Prior, L.D., Stephens, H.C. and Bowman, D.M. (2015). Macroecology of Australian tall eucalypt forests: baseline data from a continental-scale permanent plot network. PLOS ONE 10: e0137811.

Funding

Field Naturalists Society of South Australia, Lirabenda Endowment Fund (LEF) grant

Terrestrial Ecosystem Research Network

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