Estimating net climate impacts of timber production and utilization in fossil fuel intensive material and energy substitution

Abstract

We utilized an ecosystem model and life cycle assessment tool for studying carbon flows between the ecosystem, technosystem, and atmosphere for scenarios utilizing forest biomass (biosystem) against fossil fuel intensive materials (fossil system). The net climate impacts were studied for a Norway spruce (Picea abies (L.) Karst.) stand over two consecutive rotation periods (2 × 80 years) in the boreal conditions in central Finland (62°N, 29°E). The effects of alternative forest management on the carbon dynamics in the biosystem were studied in comparison with the fossil system by using an unmanaged and baseline thinning regime. The results showed that the biosystem produced carbon benefits compared with the similar system with the use of fossil fuel intensive materials and energy. The unmanaged stand stored the highest amount of carbon and retained carbon the longest when solely the ecosystem was considered. Studying the ecosystem and the technosystem together, the biosystem was found effective in storing and increasing the residence of carbon with or without changing the life span of biomass-based products. We found that the increase of the life span of biomass-based products could reduce emissions up to 0.28 t CO2·ha−1·year−1 depending on the management regimes over the study period. The increased stocking regimes could increase negative net climate impact by 47% over the study period compared with the use of baseline thinning in the biosystem. The proper climate mitigation strategies should consider the benefits from forest management and forest biomass in storing carbon into both the ecosystem and technosystem.

GHG displacement factors of harvested wood products: the myth of substitution

“…Thus, if the f nw and f w terms are understood as measures for fossil emissions only, the corresponding DF value promises unrealistic GHG benefits [18][19][20] . Authors who are aware of this difficulty account separately carbon stock variations in forest and in wood-products 7,[21][22][23][24][25][26] . Such an approach is valid as far as the interactions between the forest and wood-product carbon pools are correctly taken into account, but this does not remove the ambiguity of the displayed DF values.…”

Climate impacts of carbon sequestration of forests and material substitution by energy biomass and harvested wood products under boreal conditions

“…The LCA tool utilized the SIMA model outputs (i.e., the NEE, and timber and energy biomass yields) to estimate annual net CO2 exchange (Cnet, g CO2 m 2 a -1 ), as caused by all the main phases included in forest production and biomass utilization in substitution of fossil-based materials and fuels (Kilpeläinen et al 2011;Alam et al 2017). In addition to NEE, the Cnet included CO2 emissions from the forest management, manufacturing of wood products from timber, the degradation of wood products, and combustion of energy biomass and of the processing waste of timber (Papers I-III).…”

“…The impacts of climate change on carbon sequestration in forests and consequent effects on mitigation were excluded from the analysis. The LCA tool (Kilpeläinen et al 2011) has previously been used to study the Cnet of forest biomass production and utilization, inside and outside forest ecosystems (Routa et al 2011a;Alam et al 2012Alam et al , 2013Alam et al , 2017Kilpeläinen et al 2012Kilpeläinen et al , 2014Kilpeläinen et al , 2016bTorssonen et al 2016). In this work, the ALCA (Papers II, III) utilized all the flows of ecosystem and technosystem carbon in calculating Cnet for management and harvesting scenarios.…”

“…Use of high displacement factors also favored earlier final fellings and the use of energy biomass in substitution (Paper III). Therefore, in assessing the climate impacts of forest-based biosystems in the long term, the short-term development of sinks, integrated with substitution impacts and stocks of wood products, should be considered (Eriksson et al 2007;Lippke et al 2011;Alam et al 2017;Smyth et al 2017aSmyth et al , 2017b.…”

Substitution and carbon storage impacts of harvested wood products - Effects of increased cascading with different market responses

“…Although the substitution impacts of wood-based products are widely recognised [e.g. [19][20][21][22] the phenomenon is still relatively poorly understood in relation to the extended service life of wood-based products [23] and cascade use of wood [12]. Producing longer-lifetime products does not necessarily lead to higher substitution impacts and vice versa, which means that their combined impacts need to be studied case by case.…”