Managing temperate forests for carbon storage: impacts of logging versus forest protection on carbon stocks

Abstract

Abstract. Management of native forests offers opportunities to store more carbon in the land sector through two main activities. Emissions to the atmosphere can be avoided by ceasing logging. Removals of carbon dioxide from the atmosphere can be increased by allowing forests to continue growing. However, the relative benefits for carbon storage of managing native forests for wood production versus protection are contested. Additionally, the potential for carbon storage is impacted upon by disturbance events, such as wildfire, that alter the amount and longevity of carbon stocks.Using a case study of montane ash forests in southeastern Australia, we demonstrated that the total biomass carbon stock in logged forest was 55% of the stock in old growth forest. Total biomass included above-and belowground, living and dead. Biomass carbon stock was calculated spatially as an average across the landscape, accounting for variation in environmental conditions and forest age distribution. Reduction in carbon stock in logged forest was due to 66% of the initial biomass being made into products with short lifetimes (,3 years), and to the lower average age of logged forest (,50 years compared with .100 years in old growth forest). Only 4% of the initial carbon stock in the native forest was converted to sawn timber products with lifetimes of 30-90 years.Carbon stocks are depleted in a harvested forest system compared with an old growth forest, even when storage in wood products and landfill are included. We estimated that continued logging under current plans represented a loss of 5.56 Tg C over 5 years in the area logged (824 km 2 ), compared with a potential gain of 5.18-6.05 TgC over 5 years by allowing continued growth across the montane ash forest region (2326 km 2 ). Avoiding emissions by not logging native forests and allowing them to continue growing is therefore an important form of carbon sequestration. The mitigation value of forest management options of protection versus logging should be assessed in terms of the amount, longevity and resilience of the carbon stored in the forest, rather than the annual rate of carbon uptake.

Carbon in Mature Native Forests in Australia: The Role of Direct Weighing in the Derivation of Allometric Equations

“…Their value, however, was in good agreement with the sub-regional estimates provided by the local State Forest agency (VicForests) for pure mountain ash stands in the Central Highlands of Vic (approximately 287 t C/ha) [19]. Keith et al [41] calculated stem and branch volumes using an allometric equation for mountain ash [28] based on tree diameter (accounting for stem buttressing and internal wood decay), and multiplied by wood density and carbon concentration. There was good agreement between the AGC reported in our study and those in [41] for 1939 regrowth mountain ash stands.…”

“…Keith et al [41] calculated stem and branch volumes using an allometric equation for mountain ash [28] based on tree diameter (accounting for stem buttressing and internal wood decay), and multiplied by wood density and carbon concentration. There was good agreement between the AGC reported in our study and those in [41] for 1939 regrowth mountain ash stands. However, the productivity of the mountain ash study site was higher than typical 1939 mountain ash regrowth stands.…”

The importance of managing and conserving large old trees: a case study from Victorian Mountain Ash forests

“…Keith et al (2009) suggested that Mountain Ash forests are the most carbon-dense forests on earth. They store vast amounts of carbon, particularly when they have not been disturbed by industrial logging (Keith et al 2014). As in many forest types globally, large old trees contribute a significant proportion of the total carbon biomass stored in individual forest stands.…”

“…This has other key advantages; for example, a larger old growth estate will have fire suppression benefits as well as creating potentially suitable post-fire habitat for animals such as Leadbeater's Possum Lindenmayer et al 2015). In addition, an increased old growth forest estate would have major ecosystem service benefits such as increased levels of carbon storage (Keith et al 2014) and water production (Vertessy et al 2001;Viggers et al 2013).…”

Reconstructing European forest management from 1600 to 2010

“…More recently, evidence is accumulating that forest management (defined as forest remaining forest but undergoing tree or other biomass removal, clear-cuts, fire suppression and/or species change) may also have substantial effects on the atmospheric CO 2 concentration (Hudiburg et al, 2011(Hudiburg et al, , 2013Keith et al, 2014) in addition to affecting the surface climate through changes in albedo, evapotranspiration and surface roughness (Jackson et al, 2005(Jackson et al, , 2008Randerson et al, 2006;Rotenberg and Yakir, 2010;Luyssaert et al, 2014;Otto et al, 2014). Hence, to fully understand the impact of the large-scale application of forest management, taking into consideration only the carbon balance is not sufficient.…”