A Life Cycle Assessment of Glued Laminated Timber (Glulam) Production in Indonesia

Abstract

The building construction sector is one of the most carbon-intensive industries, contributing nearly 40% of global energy-related CO2 emissions. In tropical countries, rapid urbanization and economic growth amplify this impact, highlighting the need to reduce both operational and embodied carbon. While mass timber is gaining traction as a low-carbon solution in temperate regions, its potential in tropical areas remains underexplored. As the country of this case study, Indonesia offers a unique opportunity to harness the environmental benefits of mass timber due to its abundant wood resources, strong wood industry, and supportive climate policies. However, challenges such as land use change remain a major concern. This research aims to document the mass timber supply chain and perform a cradle-to-gate LCA of glued laminated timber (glulam) produced in Indonesia, with the consideration of land use and land use change (LULUC). The results demonstrate the potential of glulam produced in Indonesia to contribute positively to climate change mitigation. The production of 1 m3 of glulam in Indonesia results in 523.26 kg CO2 eq. of fossil emissions, while 914.11 kg CO2 eq. of biogenic carbon is stored. Thus, the overall product's carbon balance is -390.85 kg CO2 eq. Two land use change scenarios were considered to reflect conditions where logs are harvested from forest lands that have undergone conversion. One scenario was conversion from primary to secondary dryland forest, representing forest degradation, while the other was conversion from dry shrubs to secondary dryland forest, representing forest gains. For the forest gain scenario, the product's overall climate impact becomes -426.75 kg CO₂ eq. In contrast, forest degradation raises it to 821.48 kg CO₂ eq. The forest degradation scenario takes away the biogenic carbon sequestration credit while still accounting for all the biogenic and fossil emissions throughout the product's life, resulting in a significantly higher climate impact. This highlights the importance of sourcing wood from sustainably managed forests to claim the carbon benefits of wood products.