Premature defoliation under drought may reduce hydraulic risk but at the expense of nutrient and carbon imbalance in Quercus pyrenaica
Researcher:
Ferrio Díaz, Juan Pedro
Congress:
XVI Congreso Nacional de la AEET
Participation type:
Póster
Other authors:
Juan Pedro Ferrio (speaker); José Victor dos Santos-Silva; José Javier Peguero-Pina; Ana López-Ballesteros; Eustaquio Gil-Pelegrín; Rubén Martín-Sánchez; Domingo Sancho-Knapik
Year:
2023
Location:
Almería
Publication:
Juan Pedro Ferrio (speaker); José Victor dos Santos-Silva; José Javier Peguero-Pina; Ana López-Ballesteros; Eustaquio Gil-Pelegrín; Rubén Martín-Sánchez; Domingo Sancho-Knapik. Premature defoliation under drought may reduce hydraulic risk but at the expense of nutrient and carbon imbalance in Quercus pyrenaica. Póster presentado en XVI Congreso Nacional de la AEET (Almería, 16 - 20 de octubre de 2023).
In the last decades, thinning of abandoned coppices has been promoted to reduce forest decline. However, the ability of these treatments to reduce vulnerability in the mid-term remains unclear. Here, we assessed the response to a prolonged drought in summer 2022 of Quercus pyrenaica stands with different forest treatments in Moncayo (unthinned forest in favourable and unfavourable sites -UTF, UTU, dehesa -D and middle forest -MF). We hypothesized that thinned forests will be less vulnerable to drought, due to reduced competition. From early July, we observed a premature defoliation in unthinned forests, starting in less favourable sites (UTU). Moderate defoliation was later observed in UTF (late July), DE (end of August) and MF (late September). In August, unthinned sites showed significantly lower predawn water potential (-3.0 ±0.15 MPa) than DE and MF (-1.7 ±0.16 MPa), reaching similar values in all sites by early October (-2.9 ±0.08 MPa). The site with the earliest defoliation (UTU) showed a negligible loss of conductivity (PLC<20%), not differing significantly from an additional site chosen as reference for PLC and nutrients (near-optimal location, thinned to high forest -HF). Conversely, the unthinned site with moderate defoliation (UTF) and DE showed significantly higher PLC (>40%), with intermediate values in MF. Nutrient analyses revealed limited Phosphorus resorption (<40%) in senescing leaves from unthinned sites in August, regardless of site quality, as compared to ca. 80% in naturally senescing leaves in November (HF). Our results indicate that premature defoliation prevented hydraulic failure, but at the expense of nutrient loss.
In the last decades, thinning of abandoned coppices has been promoted to reduce forest decline. However, the ability of these treatments to reduce vulnerability in the mid-term remains unclear. Here, we assessed the response to a prolonged drought in summer 2022 of Quercus pyrenaica stands with different forest treatments in Moncayo (unthinned forest in favourable and unfavourable sites -UTF, UTU, dehesa -D and middle forest -MF). We hypothesized that thinned forests will be less vulnerable to drought, due to reduced competition. From early July, we observed a premature defoliation in unthinned forests, starting in less favourable sites (UTU). Moderate defoliation was later observed in UTF (late July), DE (end of August) and MF (late September). In August, unthinned sites showed significantly lower predawn water potential (-3.0 ±0.15 MPa) than DE and MF (-1.7 ±0.16 MPa), reaching similar values in all sites by early October (-2.9 ±0.08 MPa). The site with the earliest defoliation (UTU) showed a negligible loss of conductivity (PLC<20%), not differing significantly from an additional site chosen as reference for PLC and nutrients (near-optimal location, thinned to high forest -HF). Conversely, the unthinned site with moderate defoliation (UTF) and DE showed significantly higher PLC (>40%), with intermediate values in MF. Nutrient analyses revealed limited Phosphorus resorption (<40%) in senescing leaves from unthinned sites in August, regardless of site quality, as compared to ca. 80% in naturally senescing leaves in November (HF). Our results indicate that premature defoliation prevented hydraulic failure, but at the expense of nutrient loss.