High-Density Olive Groves Shown to Capture More Carbon Than Traditional Plantings

Summary

High-den­sity olive groves cap­ture sig­nif­i­cantly more car­bon diox­ide per hectare than tra­di­tion­ally planted groves, accord­ing to the GO Olive Carbon Balance pro­jec­t’s ini­tial results. Researchers com­pared dif­fer­ent olive grove man­age­ment mod­els and plant­ing den­si­ties in Andalusia and Castilla-La Mancha to assess car­bon seques­tra­tion rates, find­ing that higher plant­ing den­si­ties exhib­ited the high­est car­bon cap­ture rates.

The first results of the GO Olive Carbon Balance project show that high-den­sity olive groves cap­ture sig­nif­i­cantly more car­bon diox­ide per hectare than tra­di­tion­ally planted groves.

Researchers from the Spanish Association of Olive Growing Municipalities (AEMO) AgroecoliveLab and the University of Jaén com­pared dif­fer­ent olive grove man­age­ment mod­els and plant­ing den­si­ties across sev­eral farms oper­ated by pro­duc­ers and coop­er­a­tives in Andalusia and Castilla-La Mancha. The goal was to assess how effec­tively each sys­tem sequesters car­bon diox­ide.

The researchers con­firmed that all types of olive groves cap­ture car­bon diox­ide, stor­ing it in their wood. However, they found that ​“olive groves with higher plant­ing den­si­ties exhibit the high­est car­bon cap­ture rates.”

High-den­sity groves, defined as those planted with between 900 and 1,400 trees per hectare, cap­tured an aver­age of 6.4 tons of car­bon diox­ide per hectare per year.

The most pro­duc­tive site in the study was a high-den­sity olive grove in Lora del Río, in the province of Seville, which cap­tured nearly 12 tons of car­bon diox­ide per hectare annu­ally.

By com­par­i­son, tra­di­tional olive groves with 100 to 150 trees per hectare sequestered an aver­age of 1.2 tons of car­bon diox­ide per hectare per year. Medium-den­sity groves, with 200 to 300 trees per hectare, cap­tured an aver­age of 1.1 tons.

Despite hav­ing 1,800 to 2,000 trees per hectare, the super-high-den­sity groves ana­lyzed in the study cap­tured an aver­age of 2.2 tons of car­bon diox­ide per hectare annu­ally. The researchers attrib­uted the lower seques­tra­tion rates to the trees’ younger age.

“These amounts are sim­i­lar to or even greater than the CO2 equiv­a­lent emit­ted in field oper­a­tions,” wrote Roberto García, a pro­fes­sor of ani­mal and plant biol­ogy at the University of Jaén, in a blog post. ​“In prac­ti­cal terms, this means that olive groves can not only approach cli­mate neu­tral­ity but can also actively con­tribute to mit­i­gat­ing cli­mate change.”

In the sub­se­quent phases of the project, researchers will ana­lyze how soil man­age­ment, prun­ing, fer­til­iza­tion, phy­tosan­i­tary treat­ments and cover crop cul­ti­va­tion influ­ence car­bon seques­tra­tion in olive groves.

Once a sci­en­tific frame­work is estab­lished to deter­mine the car­bon bal­ance of dif­fer­ent olive grove sys­tems and plant­ing den­si­ties, the team plans to develop an algo­rithm to cal­cu­late car­bon bal­ances and an appli­ca­tion to val­i­date car­bon cred­its.

The researchers also expect the find­ings to inform best prac­tices for increas­ing car­bon seques­tra­tion in olive groves.

The GO Olive Carbon Balance project is one of sev­eral ini­tia­tives exam­in­ing how olive groves sequester car­bon and how this capac­ity could be mea­sured and mon­e­tized through car­bon cred­its.

In May, the International Olive Council launched a pilot project seek­ing vol­un­teer pro­duc­ers to cal­cu­late how much car­bon diox­ide their groves sequester using an online tool to gen­er­ate car­bon cred­its.

Meanwhile, a sep­a­rate group of Andalusian researchers behind the C‑Olivar project stud­ied how cul­ti­va­tion prac­tices affect car­bon seques­tra­tion.

They found sig­nif­i­cant dif­fer­ences between man­age­ment sys­tems, with seques­tra­tion rang­ing from 0.6 to 2.6 tons of car­bon diox­ide equiv­a­lent per hectare. Groves with the high­est seques­tra­tion lev­els typ­i­cally fea­tured ground cover and health­ier soils.