Feasibility of Planting Trees around Buildings as a Nature-Based Solution of Carbon Sequestration—An LCA Approach Using Two Case Studies

Abstract

In response to Canada’s commitment to reducing greenhouse gas emissions and to making pathways to achieve carbon neutral buildings, this paper presents two real case studies. The paper first outlines the potential of trees to absorb CO2 emissions through photosynthesis, and the methods used for the estimation of their annual carbon sequestration rates. The net annual carbon sequestration rate of 0.575 kgCO2eq/m² of tree cover area is considered in our study. Then, this paper presents the carbon life cycle assessment of an all-electric laboratory at Concordia University and of a single-detached house, both located in Montreal. The life cycle assessment (LCA) calculations were performed using two software tools, One Click LCA and Athena Impact Estimator for Buildings. The results in terms of Global Warming Potential (GWP) over 60 years for the laboratory were found to be 83,521 kgCO2eq using One Click LCA, and 82,666 kgCO2eq using Athena. For the single-detached house that uses natural gas for space heating and domestic hot water, the GWP was found to be 544,907 kgCO2eq using One Click LCA, and 566,856 kgCO2eq using Athena. For the all-electric laboratory, a garden fully covered with representative urban trees could offset around 17% of the total life cycle carbon emissions. For the natural gas-powered single-detached house, the sequestration by trees is around 3% of the total life cycle carbon emission. This paper presents limits for achieving carbon neutral buildings when only the emissions sequestration by trees is applied, and discusses the main findings regarding LCA calculations under different scenarios.

Life Cycle Assessment of the Environmental Benefits of Using Wood Products and Planting Trees at an All-Electric University Laboratory

“…The literature review provided in this paper also expands the literature presented by Grossi et al [28], with a focus on LCA standards and methodologies to quantify the benefits related to nature-based solutions and the end-of-life treatment of biogenic materials.…”

“…Alternatively, there are other design strategies that could be integrated into the portfolio of sustainable solutions for buildings. In the case of nature-based solutions, there is only a small number of papers [28,41,42] that account for the direct carbon sequestration of trees. None of these studies includes the assessment of biogenic carbon content or the consideration of end-of-life benefits from wood products among the strategies to reduce the carbon footprint of buildings.…”

“…When necessary, additional information about thickness, density, and other properties was provided. Then, the next input was the annual electricity consumption, which was previously estimated based on the simulation results described by Grossi et al [28]. The last software input was the vegetation carbon withdrawals, (i.e., the number and type of trees that could be planted around the building).…”

“…This case study is an expansion of the results presented by Grossi et al [28] for the life cycle assessment of a recently built research facility located at Concordia University, in Montreal, with a focus on nature-based solutions and their share of contribution to reducing the carbon footprint of buildings.…”

LCA and Scenario Analysis of Building Carbon Emission Reduction: The Influencing Factors of the Carbon Emission of a Photovoltaic Curtain Wall

“…The LCA method is commonly employed to calculate the carbon emissions associated with a product throughout its whole life cycle, including raw materials, production, use, and disposal. In recent studies, Grossi et al [33] used One Click LCA and Athena Impact Estimator for Buildings to evaluate the life cycle of an all-electric laboratory at Concordia University in Montreal. This indicates the application of LCA in assessing the environmental impact of specific buildings.…”