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Atherton, Australia

Van Oosterzee P.,Biocarbon Pty Ltd | Van Oosterzee P.,Charles Darwin University | Preece N.,Biome5 Pty Ltd | Preece N.,Charles Darwin University | And 2 more authors.
Conservation Letters | Year: 2010

The agriculture, forestry, and other land-use sector is a crucial sector, second only to the energy sector, in fighting climate change, and provides an important greenhouse gas abatement opportunity for the world. Recently, released figures for Australia, for example, suggest that agriculture, forestry, and other land-uses, which depend on healthy functioning ecosystems, could abate as much as three quarters of the country's emissions. The United Nations Framework Convention on Climate Change was concerned primarily with ecosystems and humankind, but the Kyoto Protocol of the Convention forfeited the potential of using agriculture, forestry, and other land-uses for global climate mitigation. This had the effect of decoupling biodiversity and ecosystems from carbon pollution reduction and climate change considerations. The Australian Carbon Pollution Reduction Scheme, one of the first emission trading schemes in the world to follow Kyoto "rules," excludes the agriculture, forestry, and other land-use sector, apart from plantation reforestation, potentially creating perverse incentives that themselves can turn into threatening ecological processes. We use Australia and its emerging emissions trading scheme as a case study of the potential effects of this decoupling, and demonstrate the potential impacts on a landscape-scale regional greenhouse gas abatement and carbon sequestration project. ©2010 Wiley Periodicals, Inc. Source


Preece N.D.,Biome5 Pty Ltd | Preece N.D.,James Cook University | Preece N.D.,Charles Darwin University | van Oosterzee P.,James Cook University | And 3 more authors.
Ecological Management and Restoration | Year: 2013

Forest restoration efforts in Australia's Wet Tropics establish <100 ha/year, compared with 20-year average clearing rates of 1661 ha/year. Establishment costs are serious impediments to restoration efforts. Costs range from $25,000 to $67,000/ha, compared with less than $5,000/ha in other areas using other methods. Some of this difference stems from methods used to plant trees. Augered holes are used commonly in environmental plantings, whereas planting spades are used mostly in forestry plantings. To determine the most cost-effective planting method between auger and spade planting methods, we compared the planting costs and the survival and growth of seedlings of local rainforest species, The speed of planting with a spade is on average four times quicker than with an auger, whereas the survival (range = 89-94%, spade vs auger respectively), and growth (slightly greater height growth for auger planted individuals) rates were only marginally different. Given these results, using planting spades is a cost-effective alternative to augering holes. © 2012 Ecological Society of Australia. Source


Preece N.D.,Biome5 Pty Ltd | Preece N.D.,Charles Darwin University | Preece N.D.,James Cook University | Crowley G.M.,James Cook University | And 4 more authors.
Forest Ecology and Management | Year: 2012

Revenue from carbon credits from rainforest stands could encourage reforestation for biodiversity conservation on private land in north-eastern Queensland, Australia. Current models and allometrics for estimating carbon, however, are not calibrated against sites in the region and underestimate carbon stocks. We assess the accuracy of the two accepted methods to estimate carbon stocks in Australian rainforests: FullCAM and the Keith et al. (2000) allometric. We also assess the effect of FullCAM's discounting of small stems (2.5-10cm) to carbon stocks, and compare the carbon benefits of the three reforestation methods in the region to identify planting configurations with the best carbon sequestration potential. We sampled 27 rainforest stands in north-eastern Queensland. Using these data we calculated above-ground biomass (AGB) using the Keith allometric and derived the above-ground carbon (AGC). We compared our estimates across three reforestation methods with the FullCAM modelled estimates for the same sites, and with estimates derived from two global rainforest allometrics (Brown, 1997; Chave et al., 2005). The Keith allometric estimated that planted forests yielded on average 20Mg of tradable carbon ha -1y -1 (i.e. CO 2-equivalent), with no differences between plantation forests and environmental plantings, although the former had more large diameter stems. Small stems (<10cm) accounted for 15.1% of AGB in plantings <20years old. However, even excluding these, the estimates using the Keith allometric were 19.5% greater than those of FullCAM; the Chave allometric 40.4% greater; and the Brown allometric 54.9% greater. More thorough forest mensuration using actual tree volumes and densities is required to determine a biomass allometric function for rainforests in the region. Until then, we recommend the Chave allometric function. It provides intermediate values, is based on the widest range of tropical trees and has been shown to be accurate away from the sites used for its development. This study demonstrates the inadequacy of current methods for estimating carbon stocks in rainforest plantings in north-eastern Queensland. A tailored allometric and the re-parameterisation of FullCAM is needed to reflect both the region's environmental characteristics and the vegetation structure of young reforestation stands. Current estimates deprive landholders of financial incentives and underestimate the national greenhouse gas benefits of tree planting in the Wet Tropics. © 2011 Elsevier B.V. Source


Paz C.P.,James Cook University | Paz C.P.,Center for Tropical Environmental and Sustainability Science | Goosem M.,James Cook University | Goosem M.,Center for Tropical Environmental and Sustainability Science | And 8 more authors.
Forest Ecology and Management | Year: 2016

Tropical forests are major sinks of terrestrial carbon (C) both above- and below-ground. As a consequence their destruction and degradation is considered the second largest anthropogenic source of carbon dioxide to the atmosphere. Also contributing to the changing dynamics of the global carbon cycle is the widespread and significant expansion of secondary forest. Secondary forests that colonise abandoned agricultural lands can potentially recover above-ground C stocks to historical levels in a few decades. However, the dynamics of below-ground C stored as soil C stocks are unaccounted for in several tropical regions. Similarly, although parent materials are known to differ in chemical and physical properties, little is known about the relationships of soil C stocks with environmental predictors and whether they interact with soil types during natural forest regeneration. We investigated whether soil organic carbon (SOC) stocks change with secondary forest age in two contrasting soil types (derived from either basalt or granite). Soil and vegetation parameters were analysed to determine the best predictors of SOC stock changes in secondary forests. SOC stocks from 24 secondary forests (up to 69 years since pasture abandonment) were compared with those from active pastures and mature forests. We found that clay-rich soils (originating from basalt parent material) store higher amounts of SOC, although these stocks remain unchanged as secondary forests matured. In contrast, SOC stocks in granite soils tend to be lower in young secondary forests and increase rapidly to levels comparable to mature forests. Moreover, our analysis indicated that soil pH and woody plant diversity are strong candidates as predictors of SOC stock variations, yet it appears this is within the context of soil type. Our results support the contention that models predicting SOC stocks during forest succession should not rely only on secondary forest age. Instead, predictions of SOC stocks can be improved with the inclusion of basic information on vegetation cover and soil type (especially soil texture). © 2016 Elsevier B.V. Source


Preece N.D.,James Cook University | Preece N.D.,Charles Darwin University | Preece N.D.,Biome5 Pty Ltd | Lawes M.J.,Charles Darwin University | And 6 more authors.
Forest Ecology and Management | Year: 2015

Few measurements for carbon sequestration, ratio of above-ground to below-ground biomass and wood density exist for young trees. Current allometric models are mostly for mature trees, and few consider trees at the sapling stage. Over four years we monitored the growth rates, from seedling to the sapling stage, of 490 trees (five native species) in environmental plantings, in the Wet Tropics of north-eastern Australia. Our biomass estimates were greater by several orders of magnitude in the first year (6× 10-3Mgha-1 cf. 4× 10-6Mgha-1), and two orders of magnitude less at four years than those derived from the national carbon accounting model (5× 10-1Mgha-1 cf. 13Mgha-1). We destructively sampled 37 young trees to accurately estimate the variation in below-ground and above-ground biomass (AGB) with stem size, and to derive a best fit model for predicting sapling biomass: lnAGB=-5.092+0.786 ln(Diam.base)2Height. Biomass expansion factors for young tree species ranged from 1.71 to 2.44, higher than average for tropical forests. Root:shoot ratios are consistent with mean estimates for mature rainforest. Stem wood densities ranged from 0.444 to 0.683Mgm-3 for the five species measured, which was 6.5% lower than published estimates for three of the species, and 12% and 27% higher for two species. Relative growth rates were faster for species with lower wood density in the first four years, but these species also had the lowest survival over the same period. The findings are significant for a number of reasons. Ecologically, they indicate that young rainforest trees invest more in leaves and branches than in stem growth. From a survival perspective, in the context of rainforest restoration, it is best to invest in species with higher wood densities. From a carbon accounting point of view, refinements to the models used for national carbon accounting are required that include the contribution of the sapling stage. Sapling growth rates were significantly different from those assumed in the national model, requiring growth rates to be increased after four years (as opposed to after 2years in the national model) before reaching an asymptote at some time in the future. This adjustment is essential to enable carbon farmers to judge the time it takes to receive returns from investment. Policies that encourage carbon plantings should take into account that young plantings grow slower than predicted by current national carbon accounting models. © 2015 Elsevier B.V. Source

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