Wallaby Creek Flux Data Release 2022_v1 

This data release consists of flux tower measurements of the exchange of energy and mass between the surface and the atmospheric boundary-layer in semi-arid eucalypt woodland using eddy covariance techniques. It been processed using PyFluxPro (v3.3.3) as described in Isaac et al. (2017), https://doi.org/10.5194/bg-14-2903-2017. PyFluxPro takes data recorded at the flux tower and process this data to a final, gap-filled product with Net Ecosystem Exchange (NEE) partitioned into Gross Primary Productivity (GPP) and Ecosystem Respiration (ER). For more information about the processing levels, see https://github.com/OzFlux/PyFluxPro/wiki .

The forest is classed as a tall, wet sclerophyll forest, and the dominant Eucalyptus Regnans or Mountain Ash trees have an average canopy height of 75m. The site contains a chronosequence of (20, 80 and 300) stand ages that were established during fires occurring over the last 300 years. The area is assigned the IUCN Category II (National Parks) of the United Nations’ list of National Parks and protected areas, which means that park is primarily managed for ecosystem conservation. The catchment area is dominated by Mountain Ash, the world’s tallest flowering plant (angiosperm). Trees can reach heights of more than 90 metres in areas with high rainfall and fertile soil. Mountain ash forests are confined to the cool mountain regions with elevations ranging from 460 - 1100m and average rainfalls of 1100-2000mm. These trees are well distributed throughout Victoria’s Central Highlands including the Otway Ranges and Strzlecki Ranges; they are also found in Tasmania. The catchment area contains a portion of the Mt Disappointment range, the Divide and the headwaters of Wallaby Creek and Silver Creek, and much of the slopes are characterised as flat to moderate.

The station itself is located within an old growth stand with individual trees as old as 300 years. Below the dominant canopy lies a temperate rainforest understorey consisting of Pomaderris aspera and Olearia argophylla species, which are 10-18 metres tall. The lower layers of vegetation are dominated by tree ferns (Cyathea australis and Dicksonia antartica) and extensive tracts of rosette and rhizonic ferns (Polystichum proliferum and Blechnum wattsii) as well as Acacia trees.

The major soil type within the forest is krasnozemic soils, which are friable red/brown, with high amounts of organic matter in the upper 20 – 30cm. However, the composition of krasnozemic soils is not homogenous, but rather a variation with altitude can be observed; lower altitudes inhabit grey-yellow podsolised soils compared to higher altitudes of the Kinglake and Hume plateau where the soil composition is krasnozemic loams. The clay content of these soils increases with depth until at least 200 cm deep, where after a transition soils contain rock fragments. The elevation is approximately 720 metres.

The original station was destroyed in February 2009 by bushfires. Before the bushfire, the main mast stood at 110m. In March 2010, a replacement station was established and sat at a height of 5m. Data from the site has been recorded from May 2010 onwards. As the station is relatively new, the post fire instrumentation is currently not as diverse when compared to the pre-fire instrumentation. The climate of the study area is classified as a cool, temperate zone, with the highest temperatures occurring during the summer months of December – February (13.8 – 22.5°C), whilst the coolest temperatures are experienced in May and August (4.7 – 9.2°C). Average annual precipitation is 1209mm, with a maximum rainfall occurring in June (Ashton, 2000). The study site experiences foggy conditions after sunset during autumn and winter. 

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. The station was established in August 2005 by Monash University as part of an ARC funded sustainable futures project, number DP0451247 and was operated in collaboration with Charles Darwin University and University of Alaska Fairbanks and supported by TERN. The flux station was part of the Australian OzFlux Network and contributed to the international FLUXNET Network. 

The research aim of the Wallaby Creek flux station is to understand the complex coupling of carbon, water and energy cycles within Australia's old growth temperate forests over various scales in order to assess the impact of future environmental change including to:
measure exchanges of carbon dioxide, water vapour and energy between an old growth, tall forest and the atmosphere using micrometeorological techniques
quantify the carbon sink/source of a temperate, old growth Mountain Ash forest and identify the contribution of such forests to the continents' National Carbon Inventory
provide a database of microclimate and ecological parameters for use in carbon and water modelling projects
investigate how carbon cycles change over successional time scales (decadal to centennial). 

All flux raw data is subject to the quality control process OzFlux QA/QC to generate data from L1 to L6. Levels 3 to 6 are available for re-use. Datasets contain Quality Controls flags which will indicate when data quality is poor and has been filled from alternative sources. For more details, refer to Isaac et al (2017) in the Publications section, https://doi.org/10.5194/bg-14-2903-2017 .