Life cycle analysis of a garden: CO2 emissions and capture

Extending carbon footprint assessment to garden design: Margot Dudkiewicz-Pietrzyk's Polish studio

The "secret" emissions of city gardens — Even gardens have an environmental impact: a Polish study outlines the way to calculate their carbon footprint (Photo: Envato)

Parks and gardens They're good for the environment. It's natural to think so. Yet, urban greenery isn't climate-neutral: building and maintaining a garden emits greenhouse gases; therefore, just as with buildings, we should start considering their environmental impact. carbon footprint and integrate it into decision-making processes. Also because, as emerges from a study by Margot Dudkiewicz-Pietrzyk According to the Department of Landscape Architecture at the Lublin University of Life Sciences, building a traditional garden can generate tons of CO2 equivalent.

Analysis of the entire life cycle of a garden

When analyzing the life cycle of buildings, two fundamental components of the carbon footprint can be distinguished: the operational footprint and the embodied footprint. The operational footprint includes emissions associated with the use of a building, such as heating and lighting, and has historically constituted the dominant share of total emissions. However, with the progressive improvement of the energy efficiency of buildings and the ever-increasing use of renewable energy sources, the specific weight of the operational footprint is decreasing in favor of the embodied one, which concerns emissions deriving from the extraction of raw materials, the production of materials (starting with cement), transport and construction processes.

As can be read in the study of Margot Dudkiewicz-Pietrzyk recently published in the magazine Sustainability, Also garden emissions They can be divided into operational and embedded. Although gardens and green spaces are perceived as positive for the environment, their creation and maintenance actually result in greenhouse gas emissions. As Dudkiewicz-Pietrzyk explains,

A garden's embodied carbon includes emissions associated with site preparation, the production and transportation of materials (such as surfaces, small architectural elements, or substrates), and the production of plant material. Another important factor is soil disturbance and the removal of existing vegetation, which can lead to the release of previously stored organic carbon. A garden's operational carbon is associated with its maintenance and includes, among other things, mowing, irrigation, fertilization, and other maintenance activities.

There is, however, a substantial difference between the built environment and gardens: the latter, in fact, can sequester carbon through the accumulation of biomass and organic matter in the soil, something that must be taken into due consideration in thelife cycle analysis and in net carbon balance.

Emissions from a garden: the study — To calculate the footprint of a garden, 4 factors are fundamental: the initial emissions associated with construction, the annual emissions resulting from use, the potential for CO2 sequestration and the total balance analysed in the first year of operation and over a 20-year horizon (Photo: Envato)

How do you calculate the carbon footprint of a private garden?

The study takes into consideration different types of urban greenery: private gardens, urban parks, street greenery, and roof gardens. Particularly interesting is the analysis of the carbon footprint of private gardens, which allows formulas and calculations to be put into a practical and easily visualized dimension. The author considers a fairly typical garden, with a surface area of 500 m² The layout is as follows: 200 m² of lawn, 150 m² of perennial and shrub beds, 100 m² of mineral surface, 30 m² of wooden terrace, and 20 m² of prefabricated concrete slab path. The planting plan includes 5 deciduous trees, 25 shrubs, and 200 perennials and ornamental grasses.

To calculate the carbon footprint, however, other factors must also be considered: materials needed for construction (including topsoil and mulch) and the operational model hypothesized for the garden management, which in this case involves mowing the lawn with a gasoline-powered lawnmower, moderate irrigation, no use of mineral fertilizers, and partial on-site composting of the biomass. Based on these data,

“The calculation methodology is based on four components: initial emissions associated with construction, annual emissions resulting from use, the CO2 sequestration potential of vegetation and soil, and the total balance analyzed in the first year of operation and over a 20-year horizon.”

The (surprising) emissions of a traditional garden

Il calculating the emissions of a garden It begins with those associated with its construction, which obviously have an impact on the materials used: in the case analyzed, the path with concrete slabs involves the emission of 700 kg CO2e, while the 100 m² mineral surface generates approximately 1200 kg CO2e and the small wooden terrace approximately 450 (without taking into account the carbon storage in the material).

The transportation and application of soil, aggregates, and mulch generate a total of 444 kilograms of CO2 equivalent. Plant production and transportation also account for approximately 350 kg of CO2e. The initial emissions for building such a garden amount to approximately 3,4 tons of CO2 equivalent.
In the operational phase, explains Dudkiewicz-Pietrzyk, emissions are much lower but of a recurring nature:

Mowing a 200 m² lawn with a gasoline-powered lawnmower (approximately 20 cycles per year) generates approximately 40 kg of CO2e per year. Irrigation, including water and energy consumption, accounts for approximately 25 kg of CO2e per year, while routine maintenance activities and the use of small equipment contribute approximately 20 kg of CO2e. Additional emissions associated with material replenishment and minor replanting amount to approximately 30 kg of CO2e per year. At the same time, partial on-site composting of biomass reduces emissions by approximately 15 kg of CO2e per year. Consequently, total emissions related to garden management amount to approximately 100 kg of CO2e per year.

Finally, the vegetation's capacity to absorb carbonIn this case, 5 young deciduous trees absorb a total of approximately 90 kg of CO2 per year, the flowerbeds bind approximately 53 kg, and the lawn approximately 20 kg, for a total of 163 kg per year. This specific garden, therefore, uses 54 years to offset emissions related to its construction.

The carbon footprint of traditional gardens — A traditional private garden with a high environmental impact in the Lublin region, Poland (Photo: M. Dudkiewicz-Pietrzyk, 2025)

Traditional garden vs. naturalistic approach

As the author points out, a garden conceived in this way shows a rather high initial imprint, but a few substantial changes are enough to significantly reduce its impact: reducing the area of concrete slab paths from 20 to 8 m², limiting the lawn to 100 m², extending the area of flower beds and plantations, using permeable surfaces with lighter construction and reducing operating emissions by replacing the petrol lawnmower with an electric device, you can reduce initial emissions to 2,5 t CO2e, while the annual net sequestration balance could increase to around 180-250 kg of CO2. This would reduce the compensation time to around 10-15 years, or, in a more conservative scenario, to twenty years.

Another aspect that can contribute to the sustainability of a garden is related to the approach. The same 500 m² can be designed in a traditional manner, like the garden analyzed above, or follow amore naturalistic setting:

“The naturalistic variant, assuming a reduction in the grass area (100 m²), a reduction in the areas, an increase in the flowerbed area (230 m²) and a greater number of trees (8), achieves lower initial emissions (approximately 2,56 t CO2e), while at the same time demonstrating a significantly higher sequestration potential (approximately 277 kg CO2/year) and lower operational emissions (approximately 53 kg CO2e/year). As a result, the annual positive balance amounts to approximately 224 kg CO2 and the compensation time is reduced to approximately 11–12 years; furthermore, within 20 years, the garden reaches a negative overall balance (approximately −1,92 t CO2e), becoming a net sink.”

The key factors for reducing the footprint of gardens, therefore, are: limit high-emitting materials (especially concrete and structures), reduce the area of intensively managed lawn in favor of, for example, ground cover vegetation, increase the share of durable perennial vegetation and minimize operational inputs by designing gardens with lower maintenance requirementsBut this is only the first chapter in a new way of looking at urban greenery. Future research, the author concludes, should focus on the quantitative evaluation of the proposed indicators, their testing on different types of gardens, and their integration with existing environmental assessment tools such as LCA.