Avocet carbon budget

The carbon estimates outlined below were taken from “Avocet”, a grazing property, located approximately 32 km south of Emerald in Central Queensland. The property has a total area of 4274 ha, of which about 1533 ha (36%) has been cleared for grazing, and the remainder is uncleared natural bushland. Cattle are grazed in both cleared and uncleared areas. “Avocet” is located within the Brigalow Belt Bioregion, and includes vegetation categorised in 18 Regional Ecosystems. As the property included such a wide range of Regional Ecosystems (REs) it was decided to sample only eight of the REs, (marked in bold in Table 1) and to apply the information from these sites to the other REs. At each RE one general area (site) was selected to be representative of the vegetation. Trees were measured in 200m² rectangular plots called transects. 30 transects were laid out at each site. Each transect was 50 metres long and 4 metres wide, and all were laid in a north-south direction. All trees were measured in the first three transects. Dead trees, if encountered were included in the measurements. In the remaining transects, trees were measured until thirty trees of each major tree type had been measured and then, only the number of trees was counted in each transect. All trees and bushes over 1.8 metres weremeasured. It was assumed that trees and bushes lower than this height would be susceptible to fire and may have perished in the landscape. In some REs one site was not sufficient to represent the variation in vegetation that occurred and in such cases more that one site was sampled. The stem circumference of each tree selected was measured at a height of 30 cm above the ground. From this measurement, the tree biomass was calculated using previously developed equations, which relate stem circumference, or in some cases, stem diameter, to total above-ground biomass.

以下所述的碳排放估算数据源自位于澳大利亚昆士兰州中部的艾默德南方约32公里处的“翠鸟”牧场。该牧场总面积为4274公顷，其中约1533公顷（占36%）已被清除用于放牧，其余部分为未开垦的自然林地。牛群在清除和未清除的区域均进行放牧。“翠鸟”位于布里加洛生物区域之内，包括被归类于18个区域生态系统的植被。鉴于该牧场涵盖了如此广泛的区域生态系统（REs），因此决定仅对八个REs进行采样（见表1中加粗标注），并将这些采样点的信息应用于其他REs。在每个RE中，选择了一个一般区域（即采样点）以代表植被。树木在称为横断面的200平方米矩形区域内进行测量。每个采样点布置了30个横断面。每个横断面长50米，宽4米，均沿南北方向布置。在最初三个横断面上测量了所有树木。如遇枯树，则将其包含在测量范围内。在剩余的横断面上，树木的测量直至每种主要树木类型的树木测量数量达到三十棵，然后，在每个横断面上仅计数树木的数量。所有高度超过1.8米的树木和灌木均进行测量。假设低于此高度的树木和灌木可能易受火灾影响，并可能已在景观中灭绝。在某些REs中，单个采样点不足以代表植被的变异情况，因此在这些情况下，对多个采样点进行采样。所选树木的树干胸径在距地面30厘米的高度处进行测量。通过这一测量值，利用先前开发的方程式计算树木的生物量，这些方程式将树干胸径（或在某些情况下，树干直径）与地上总生物量相关联。