Assessment of Aboveground Carbon in Primary and Selectively Harvested Tropical Forest in Papua New Guinea

Abstract

Papua New Guinea (PNG) has become the focus of climate change mitigation initiatives such as reducing emissions from deforestation and forest degradation, but defensible estimates of forest carbon are lacking. Here we present a methodology for estimating aboveground forest carbon, and apply it to a large Permanent Sample Plot system maintained by Papua New Guinea Forest Research Institute. We report the first estimates of forest carbon in lowland tropical forest in PNG. Average aboveground carbon in stems 4 10 cm diam. for 115 selectively harvested 1-ha plots in lowland tropical forest was 66.3 AE 3.5 Mg C/ha (95% CI) while for 10 primary forest plots the average was 106.3 AE 16.2 Mg C/ha. We applied ratios based on field observations, in-country studies, and the literature to estimate unmeasured pools of aboveground carbon (stems o 10 cm diam., fine litter and coarse woody debris). Total aboveground carbon was estimated at 90.2 and 120.8 Mg C/ha in selectively harvested and primary lowland forest, respectively. Our estimate for primary tropical forest is lower than biome averages for tropical equatorial forest, and we hypothesize that frequent disturbances from fire, frost, landslides, and agriculture are limiting carbon stock development. The methodology and estimates presented here will assist the PNG government in its preparedness for mitigation initiatives, are of interest to communities that are seeking to participate in voluntary carbon markets, and will encourage transparency and consistency in the estimation of forest carbon.

Advocacy coalitions, REDD+, and forest governance in Papua New Guinea: how likely is transformational change?

“…http://www.ecologyandsociety.org/vol19/iss3/art16/ al. , Fox et al 2010, illegal forest clearance under the guise of agricultural development (Filer 2011(Filer , 2012, and corruption (Transparency International 2009, Laurance et al 2011. These features are often associated with a lack of state autonomy from what can be considered as powerful vested interests driving deforestation and forest degradation, particularly foreign-owned logging companies (Laurance 2010, Melick 2010, Laurance et al 2011).…”

The Context of REDD+ in Papua New Guinea: Drivers, agents, and institutions

“…There is general agreement that current rates of commercial timber harvesting in PNG are unsustainable (Bun et al 2004, Fox et al 2010.…”

“…PNG is particularly prone to fires during El Niño-Southern Oscillation (ENSO)-induced droughts (Johns 1989, GoPNG 2010a. In terms of REDD+, frequent fires will reduce the amount of carbon stored in the country's forests, with a recent study suggesting that frequent disturbance by fire has contributed to lower levels of carbon stored in PNG's forest when compared with global tropical forest averages (Fox et al 2010). …”

“…Data from the PNGFRI sample plots were used by Fox et al (2010) to estimate above-ground carbon stocks at 120 MgC/ha in primary forest and 90.2 MgC/ ha in selectively harvested forests (the authors note that this is considerably lower than the global average for tropical forests, and note a degree of uncertainty).…”

Development of Allometric Equations for Tree Biomass in Forest Ecosystems in Paraguay

“…For a ground-based inventory, permanent sample plots allow the monitoring of carbon stocks by area (e.g. Fox et al 2010, Samreth et al 2012. Estimates of carbon stocks in living biomass can be obtained using allometric equations with measured field variables such as diameter and tree height in the plots (Metzker et al 2012).…”