Wallaby Creek Flux Data Release 2022_v2

This release consists of flux tower measurements of the exchange of energy and mass between the surface and the atmospheric boundary-layer using eddy covariance techniques. Data were processed using PyFluxPro (v3.4.7) as described by Isaac et al. (2017). PyFluxPro produces a final, gap-filled product with Net Ecosystem Exchange (NEE) partitioned into Gross Primary Productivity (GPP) and Ecosystem Respiration (ER).

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 75 m. 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 the 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 m in areas with high rainfall and fertile soil. Mountain ash forests are confined to the cool mountain regions with elevations ranging from 460 to 1100 m and average rainfalls of 1100 to 2000 mm/y. 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 to 18 m 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 elevation is approximately 720 m. The major soil type within the forest is krasnozemic soils, which are friable red/brown soils, with high amounts of organic matter in the upper 20 to 30 cm. However, the composition of krasnozemic soils is not homogenous, but rather varies with altitude. Grey-yellow podsolised soils can be found at lower altitudes, while krasnozemic loams is characteristic of the higher altitudes of the Kinglake and of the Hume Plateau. The clay content of these soils increases with depth until at least 200 cm deep, where after a transition soils contain rock fragments. 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 to 22.5 °C), whilst the coolest temperatures are experienced in May and August (4.7 to 9.2 °C). Average annual precipitation is 1209 mm, with a maximum rainfall occurring in June (Ashton, 2000). The study site experiences foggy conditions after sunset during autumn and winter.

The original station had a main mast at 110 m. This station was destroyed in February 2009 by bushfires. A replacement station was established in March 2010 and started recording in May 2010. The mast sat at a height of 5 m. The post-fire instrumentation was not as diverse as the pre-fire instrumentation.

本数据集包含采用涡度协方差（eddy covariance）技术获取的地表与大气边界层之间能量与物质交换的通量塔观测数据。数据按照Isaac等人2017年的研究方法，使用PyFluxPro（v3.4.7）进行处理。PyFluxPro可生成经过间隙填充的最终数据集，将生态系统净交换（Net Ecosystem Exchange, NEE）划分为总初级生产力（Gross Primary Productivity, GPP）与生态系统呼吸（Ecosystem Respiration, ER）。

该研究区域的森林被归类为高大湿润硬叶林（sclerophyll forest），优势树种为王桉（Eucalyptus Regnans，又名山灰树），平均冠层高度达75米。站点设置有20年、80年和300年三个林龄序列的林分，这些林分形成于过去300年间的火灾事件之后。该区域被列入联合国国家公园及保护区名录的国际自然保护联盟（IUCN）II类（国家公园），即该公园以生态系统保护为核心管理目标。流域内以山灰林为主，山灰是世界上最高的显花被子植物（angiosperm）。在高降雨且土壤肥沃的区域，山灰树高度可超过90米。山灰林仅分布于海拔460至1100米的凉爽山地，年平均降雨量为1100至2000毫米。该树种广泛分布于维多利亚州中部高地，包括奥特韦山脉（Otway Ranges）和斯特尔齐莱基山脉（Strzlecki Ranges），在塔斯马尼亚州亦有分布。该流域涵盖芒特迪萨波因特山脉（Mt. Disappointment）、大分水岭（Divide）以及沃拉比溪（Wallaby Creek）和西尔弗溪（Silver Creek）的上游区域，大部分坡面地势平缓至中等起伏。

观测站点本身坐落于一片原始老龄林内，部分树木树龄可达300年。在优势冠层下方，发育有温带雨林下层植被，包含高10至18米的疏花火索藤（Pomaderris aspera）和银叶澳菊（Olearia argophylla）。植被下层以澳洲桫椤（Cyathea australis）和南极蚌壳蕨（Dicksonia antartica）等树蕨为主，同时广泛分布着多叶耳蕨（Polystichum proliferum）和瓦茨氏乌毛蕨（Blechnum wattsii）等莲座蕨类与根状茎蕨类，以及金合欢类树木。站点海拔约720米。该森林的主要土壤类型为红棕壤土（krasnozemic soils），即结构疏松的红/棕色土壤，表层20至30厘米有机质含量较高。不过红棕壤土的组成并不均一，而是随海拔变化：低海拔区域可见灰黄色灰化土，而金莱克（Kinglake）和休姆高原（Hume Plateau）的高海拔区域则以红棕壤质土为主。此类土壤的黏粒含量随深度增加，至少在200厘米深度处仍呈递增趋势，200厘米以下的过渡层土壤含有岩石碎屑。研究区域的气候属于凉爽温带气候，夏季（12月至次年2月）最高气温介于13.8至22.5℃，最冷时段为5月和8月，气温介于4.7至9.2℃。年平均降水量为1209毫米，6月降雨量最高（Ashton, 2000）。研究站点在秋季和冬季的日落之后多雾天气。

原始观测站的主桅杆高度为110米，该站点于2009年2月被山火损毁。2010年3月重建了替代观测站，并于2010年5月开始观测数据。重建后的桅杆高度为5米，灾后布设的观测仪器种类较火灾前有所减少。