Comparing above-ground biomass among forest types in the Wet Tropics

Small stems and plantation types matter in carbon accounting

Noel Preece, Gabriel Crowley, Michael Lawes, Penny Van Oosterzee

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    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. 
    Original languageEnglish
    Pages (from-to)228-237
    Number of pages10
    JournalForest Ecology and Management
    Volume264
    DOIs
    Publication statusPublished - 2012

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    aboveground biomass
    forest types
    rain forests
    tropics
    plantation
    plantations
    stem
    reforestation
    carbon sinks
    rainforest
    stems
    planting
    carbon
    Queensland
    forest mensuration
    carbon markets
    private lands
    economic incentives
    forest plantations
    vegetation structure

    Cite this

    Preece, Noel ; Crowley, Gabriel ; Lawes, Michael ; Van Oosterzee, Penny. / Comparing above-ground biomass among forest types in the Wet Tropics : Small stems and plantation types matter in carbon accounting. In: Forest Ecology and Management. 2012 ; Vol. 264. pp. 228-237.
    @article{2dcd25bdd9ac4322a5d695e5f342de45,
    title = "Comparing above-ground biomass among forest types in the Wet Tropics: Small stems and plantation types matter in carbon accounting",
    abstract = "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. ",
    keywords = "Above ground biomass, Allometrics, Australia, Biodiversity conservation, Carbon accounting, Carbon credits, Carbon sequestration, Carbon sequestration potential, Carbon stocks, Current estimates, Current models, Environmental characteristic, Financial incentives, Forest type, Large diameter, Plantation, Plantation forests, Plantings, Private land, Queensland, Rainforest, Tree plantings, Tropical tree, Vegetation structure, Wet tropics, Biodiversity, Biomass, Carbon dioxide, Conservation, Estimation, Greenhouse gases, Plants (botany), Reforestation, Revegetation, Tropics, Carbon, aboveground biomass, allometry, calibration, carbon dioxide, carbon sequestration, data set, estimation method, greenhouse gas, mathematical analysis, numerical model, plantation, population density, rainforest, reforestation, restoration ecology, tropical forest, vegetation structure",
    author = "Noel Preece and Gabriel Crowley and Michael Lawes and {Van Oosterzee}, Penny",
    year = "2012",
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    Comparing above-ground biomass among forest types in the Wet Tropics : Small stems and plantation types matter in carbon accounting. / Preece, Noel; Crowley, Gabriel; Lawes, Michael; Van Oosterzee, Penny.

    In: Forest Ecology and Management, Vol. 264, 2012, p. 228-237.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Comparing above-ground biomass among forest types in the Wet Tropics

    T2 - Small stems and plantation types matter in carbon accounting

    AU - Preece, Noel

    AU - Crowley, Gabriel

    AU - Lawes, Michael

    AU - Van Oosterzee, Penny

    PY - 2012

    Y1 - 2012

    N2 - 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. 

    AB - 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. 

    KW - Above ground biomass

    KW - Allometrics

    KW - Australia

    KW - Biodiversity conservation

    KW - Carbon accounting

    KW - Carbon credits

    KW - Carbon sequestration

    KW - Carbon sequestration potential

    KW - Carbon stocks

    KW - Current estimates

    KW - Current models

    KW - Environmental characteristic

    KW - Financial incentives

    KW - Forest type

    KW - Large diameter

    KW - Plantation

    KW - Plantation forests

    KW - Plantings

    KW - Private land

    KW - Queensland

    KW - Rainforest

    KW - Tree plantings

    KW - Tropical tree

    KW - Vegetation structure

    KW - Wet tropics

    KW - Biodiversity

    KW - Biomass

    KW - Carbon dioxide

    KW - Conservation

    KW - Estimation

    KW - Greenhouse gases

    KW - Plants (botany)

    KW - Reforestation

    KW - Revegetation

    KW - Tropics

    KW - Carbon

    KW - aboveground biomass

    KW - allometry

    KW - calibration

    KW - carbon dioxide

    KW - carbon sequestration

    KW - data set

    KW - estimation method

    KW - greenhouse gas

    KW - mathematical analysis

    KW - numerical model

    KW - plantation

    KW - population density

    KW - rainforest

    KW - reforestation

    KW - restoration ecology

    KW - tropical forest

    KW - vegetation structure

    U2 - 10.1016/j.foreco.2011.10.016

    DO - 10.1016/j.foreco.2011.10.016

    M3 - Article

    VL - 264

    SP - 228

    EP - 237

    JO - Forest Ecology and Management

    JF - Forest Ecology and Management

    SN - 0378-1127

    ER -