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Venter M, Dwyer J, Dieleman W, Ramachandra A, Gillieson D, Laurance S, Cernusak LA, Beehler B, Jensen R, Bird MI. Optimal climate for large trees at high elevations drives patterns of biomass in remote forests of Papua New Guinea. GLOBAL CHANGE BIOLOGY 2017; 23:4873-4883. [PMID: 28560838 DOI: 10.1111/gcb.13741] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/10/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
Our ability to model global carbon fluxes depends on understanding how terrestrial carbon stocks respond to varying environmental conditions. Tropical forests contain the bulk of the biosphere's carbon. However, there is a lack of consensus as to how gradients in environmental conditions affect tropical forest carbon. Papua New Guinea (PNG) lies within one of the largest areas of contiguous tropical forest and is characterized by environmental gradients driven by altitude; yet, the region has been grossly understudied. Here, we present the first field assessment of aboveground biomass (AGB) across three main forest types of PNG using 193 plots stratified across 3,100-m elevation gradient. Unexpectedly, AGB had no direct relationship to rainfall, temperature, soil, or topography. Instead, natural disturbances explained most variation in AGB. While large trees (diameter at breast height > 50 cm) drove altitudinal patterns of AGB, resulting in a major peak in AGB (2,200-3,100 m) and some of the most carbon-rich forests at these altitudes anywhere. Large trees were correlated to a set of climatic variables following a hump-shaped curve. The set of "optimal" climatic conditions found in montane cloud forests is similar to that of maritime temperate areas that harbor the largest trees in the world: high ratio of precipitation to evapotranspiration (2.8), moderate mean annual temperature (13.7°C), and low intra-annual temperature range (7.5°C). At extreme altitudes (2,800-3,100 m), where tree diversity elsewhere is usually low and large trees are generally rare or absent, specimens from 18 families had girths >70 cm diameter and maximum heights 20-41 m. These findings indicate that simple AGB-climate-edaphic models may not be suitable for estimating carbon storage in forests where optimal climate niches exist. Our study, conducted in a very remote area, suggests that tropical montane forests may contain greater AGB than previously thought and the importance of securing their future under a changing climate is therefore enhanced.
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Affiliation(s)
- Michelle Venter
- Ecosystem Science and Management Program, University of Northern BC, Prince George, BC, Canada
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
| | - John Dwyer
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, Australia
| | - Wouter Dieleman
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
| | | | - David Gillieson
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
| | - Susan Laurance
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
| | - Bruce Beehler
- Division of Birds, Smithsonian Institution, MRC 116 National Museum of Natural History, Washington, DC, USA
| | - Rigel Jensen
- Australian Wildlife Conservancy, North-Eastern Region, Malanda, Qld, Australia
| | - Michael I Bird
- College of Science and Engineering, Centre for Tropical Environmental and Sustainability Science, James Cook University, Cairns, Qld, Australia
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Peck MR, Kaina GS, Hazell RJ, Isua B, Alok C, Paul L, Stewart AJA. Estimating carbon stock in lowland Papua New Guinean forest: Low density of large trees results in lower than global average carbon stock. AUSTRAL ECOL 2017. [DOI: 10.1111/aec.12525] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mika Robert Peck
- Department of Environment Behaviour and Ecology; School of Life Sciences; University of Sussex; Brighton BN19QG UK
| | - Graham S. Kaina
- New Guinea Binatang Research Centre; Madang Papua New Guinea
| | - Richard John Hazell
- Department of Environment Behaviour and Ecology; School of Life Sciences; University of Sussex; Brighton BN19QG UK
| | - Brus Isua
- New Guinea Binatang Research Centre; Madang Papua New Guinea
| | - Clant Alok
- New Guinea Binatang Research Centre; Madang Papua New Guinea
| | - Luda Paul
- New Guinea Binatang Research Centre; Madang Papua New Guinea
| | - Alan J. A. Stewart
- Department of Environment Behaviour and Ecology; School of Life Sciences; University of Sussex; Brighton BN19QG UK
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Vincent JB, Henning B, Saulei S, Sosanika G, Weiblen GD. Forest carbon in lowland Papua New Guinea: Local variation and the importance of small trees. AUSTRAL ECOL 2014; 40:151-159. [PMID: 26074730 PMCID: PMC4461161 DOI: 10.1111/aec.12187] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2014] [Indexed: 11/30/2022]
Abstract
Efforts to incentivize the reduction of carbon emissions from deforestation and forest degradation require accurate carbon accounting. The extensive tropical forest of Papua New Guinea (PNG) is a target for such efforts and yet local carbon estimates are few. Previous estimates, based on models of neotropical vegetation applied to PNG forest plots, did not consider such factors as the unique species composition of New Guinea vegetation, local variation in forest biomass, or the contribution of small trees. We analysed all trees >1 cm in diameter at breast height (DBH) in Melanesia's largest forest plot (Wanang) to assess local spatial variation and the role of small trees in carbon storage. Above-ground living biomass (AGLB) of trees averaged 210.72 Mg ha−1 at Wanang. Carbon storage at Wanang was somewhat lower than in other lowland tropical forests, whereas local variation among 1-ha subplots and the contribution of small trees to total AGLB were substantially higher. We speculate that these differences may be attributed to the dynamics of Wanang forest where erosion of a recently uplifted and unstable terrain appears to be a major source of natural disturbance. These findings emphasize the need for locally calibrated forest carbon estimates if accurate landscape level valuation and monetization of carbon is to be achieved. Such estimates aim to situate PNG forests in the global carbon context and provide baseline information needed to improve the accuracy of PNG carbon monitoring schemes.
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Affiliation(s)
- John B Vincent
- Plant Biological Sciences Graduate Program, University of Minnesota Saint Paul, MN, 55108, USA
| | - Bridget Henning
- Conservation Biology Graduate Program, University of Minnesota Saint Paul, Minnesota, USA
| | - Simon Saulei
- Papua New Guinea Forest Research Institute Lae, Papua New Guinea
| | - Gibson Sosanika
- New Guinea Binatang Research Center Madang, Papua New Guinea
| | - George D Weiblen
- Bell Museum and Department of Plant Biology, University of Minnesota Saint Paul, Minnesota, USA
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