Modeling Carbon Footprints of Organic Orchard Production Systems to Address Carbon Trading: An Approach Based on Life Cycle Assessment

Abstract

<jats:p>Carbon footprint is widely accepted as an indicator of greenhouse gas emissions and global warming. Modeling carbon footprints based on life cycle assessment is applied as a way to evaluate the net contribution of greenhouse gases to the atmosphere from orchard production systems over one growing year. This net balance approach considers the sources and sinks of carbon and therefore provides a better reflection of an orchard system's net contribution to climate change. Carbon footprinting of organic kiwifruit and apple production systems in New Zealand indicated that the studied systems had a net sequestration from 2.4 to 5 t of CO<jats:sub>2</jats:sub>e/ha/year and therefore can be potentially considered as carbon sinks under the Kyoto Protocol. This finding implies that the organic kiwifruit and apple orchardist can gain a monetary benefit by earning carbon credits. However, further research to improve and validate this approach is essential before it can be practically used for decision-making at the orchard level and for policymaking at the national level.</jats:p>

Carbon Sequestration by Fruit Trees - Chinese Apple Orchards as an Example

“…The total net C sink from apple orchards in China is about 27 Tg C in 2010, which is equivalent to 14 t C ha −1 . If taking the life cycling of apple trees as 25 years, the figure is similar to the reported amount for organic kiwifruit and apple production systems in New Zealand [30] . It is predicted that the capability continues growing substantially in China in the future because of the increase of growing areas and more apple orchards entering the mature stage.…”

Ecosystem services in orchards. A review

“…It is nevertheless important to estimate the contribution of orchards, especially in regions where they are highly concentrated. Studies have shown that fruit orchards such as kiwifruit, apple, peach, orange and olive could sequester from 2.4 to 12.5 t C/ha/year (Sofo et al 2005;Page et al 2011;Montanaro et al 2017). Orchards may sequester quantities of carbon similar to those of forests during their first years of life since photosynthesis activity is greater in young trees than in older ones (Wu et al 2012).…”

“…Furthermore, in most cases, carbon in fruit trees is only temporarily sequestered since the lifespan of an orchard ranges from 15 to 30 years and the trees are usually burned without any valorization at the end of their lives. Life cycle analyses show that carbon emissions may also come from other sources: CO 2 emissions by engines during weeding or fertilization might represent as much as 23% of total CO 2 emissions in intensive apple orchards (Page et al 2011). It is therefore important to precisely quantify these losses.…”

“…Some denitrification measurements have been made using methods based on labeled 15 N (Myrold 1990). Similarly, the quantities of carbon sequestered in the soil and in different tree organs at specific time scales have been used as indicators in orchards (Page et al 2011;Wu et al 2012;Zanotelli et al 2015). For these measurements, tree excavation is generally required to measure each organ's biomass, and closed gas exchange systems (e.g., Licor photosynthesis system with soil CO 2 flux chamber) are necessary to measure CO 2 emissions from the soil.…”

“…In view of this type of study, indicators of the direct impact of agricultural practices in terms of CO 2 emissions are necessary. Cumulative amounts of CO 2 emitted by crop protection products or engines operating in the orchard over the growing season can serve as a simple indicator (Page et al 2011;Alaphilippe et al 2013).…”