MARIE SKŁODOWSKA-CURIE ACTIONS Individual Fellowships (IF), Call: H2020-MSCA-IF-2016
Project acronym: REFOREST
The role of extreme drought and legacy effects of long-term manipulation of water availability on growth and reproduction of Scots pine
Project acronym: REFOREST
The role of extreme drought and legacy effects of long-term manipulation of water availability on growth and reproduction of Scots pine
Updates or News
- April 9, 2021: The third chapter (Climate sensitivity and drought seasonality determine post-drought growth recovery of Quercus petraea and Quercus robur in Europe) is now published in the Science of the Total Environment.
- August 25th 2020: Gave a talk on Climate sensitivity and drought seasonality determine post-drought growth recovery of Quercus petraea and Quercus robur in Europe at Swiss Federal Research Institute, WSL.
- May 1st, 2020: The first part of the first objective is published in Global Change Biology: Growth and resilience responses of Scots pine to extreme droughts across Europe depend on pre-drought growth conditions. Global Change Biology, 26(8): 4521-4537.
- January 21st, 2020: The second objective of the project is published in the journal Plant, Cell & Environment: Memory of environmental conditions across generations affects the acclimation potential of scots pine.
- June 5-7, 2019: Participated USYS, ETH Zurich meeting in Davos Switzerland, and presented "The potential role of transgenerational epigenetic effects for the acclimation of Pinus sylvestris L. to drought" .
- April 10-12, 2019: Participated the EGU general assembly 2019 and presented in the session Interdisciplinary Tree Ring Research: Growth responses of Scots pine (Pinus sylvestris L.) to extreme droughts: How do they vary across a 2800 km latitudinal gradient in Europe?
- February 26th, 2019: A coauthored paper leaded by Dr. Sophia Etzold of Swiss Federal Research Institute by Frontiers in Plant Science: One Century of Forest Monitoring Data in Switzerland Reveals Species- and Site-Specific Trends of Climate-Induced Tree Mortality.
- January 29th, 2019: Prsented "The potential role of transgenerational epigenetic effects for the acclimation of Pinus sylvestris L. to drought" at Swiss Federal Reserach Institute WSL.
- December 10-12, 2018: Participated the Functional Ecology Conference in Nancy France, and presented "Potential role of transgenerational epigenetic effects in acclimation to environmental changes".
- November 21st, 2018: Participate the Science day of Swiss Forest Lab in Birmensdorf, Switzerland and made a poster presentation.
- August 19-24th, 2018: Participated the CARSEQ (Carbon Sequestration) summer school at Davos, Switzerland.
- March 11-13th 2018: Participated a meeting in Berlin, Germany for collaboration related to REFOREST project.
- March 7-11th 2018: Participated the CIMAS conference at Granada, Spain for collaboration related to REFOREST project.
Project Introduction
Scots pine (Pinus sylvestris) and deciduous oak (e.g. Quercus petrea, Q. robur and Q. pubescens) are widely distributed tree species in Europe. Several recent studies conducted in southern Europe have reported drought-induced dieback of Scots pine. Many of those forests once dominated
by Scots pine are now shifting towards the dominance of oak. Drought stress has been identified as an important driving factor for forest decline and decline-induced large-scale changes in the vegetation composition. Monitoring the long-term (e.g., over the last three decades) pattern of tree-level growth in relation to drought events is important to understanding the tree-level growth resistance (direct impact of an extreme event) and resilience (trajectory of recovery after an extreme event).
In addition to tree-level responses to elevated temperature and drought, the seedling physiological response (photosynthesis and respiration) to varying growing conditions (temperature and water) is key to forecast the future forest composition of temperate forests in Europe. Tree growth is generally determined by its genetic potential and external environment through various physiological processes including seed germination, seedling establishment and survival. Recent studies demonstrate the important role of transgenerational epigenetic effects (i.e. effects resulting from changes in gene function of an organism and not from changes in DNA) for the adaptive capacity of trees. Although the epigenetic control of gene expression during drought has been shown in trees at the molecular level, its role for the net photosynthesis (carbon assimilation) and transpiration (gas exchange) rate is currently unknown.
Objectives of this study are to (1) quantify radial growth of the two common European tree species, Scots pine and oak along a latitudinal gradient from southern Spain to northern Germany with particular focus on the effects of extreme events, and (2) quantify the potential role of epigenetic effects on seed germination, seedling establishment and survival in variable growing conditions (water, temperature and shading).
Scots pine (Pinus sylvestris) and deciduous oak (e.g. Quercus petrea, Q. robur and Q. pubescens) are widely distributed tree species in Europe. Several recent studies conducted in southern Europe have reported drought-induced dieback of Scots pine. Many of those forests once dominated
by Scots pine are now shifting towards the dominance of oak. Drought stress has been identified as an important driving factor for forest decline and decline-induced large-scale changes in the vegetation composition. Monitoring the long-term (e.g., over the last three decades) pattern of tree-level growth in relation to drought events is important to understanding the tree-level growth resistance (direct impact of an extreme event) and resilience (trajectory of recovery after an extreme event).
In addition to tree-level responses to elevated temperature and drought, the seedling physiological response (photosynthesis and respiration) to varying growing conditions (temperature and water) is key to forecast the future forest composition of temperate forests in Europe. Tree growth is generally determined by its genetic potential and external environment through various physiological processes including seed germination, seedling establishment and survival. Recent studies demonstrate the important role of transgenerational epigenetic effects (i.e. effects resulting from changes in gene function of an organism and not from changes in DNA) for the adaptive capacity of trees. Although the epigenetic control of gene expression during drought has been shown in trees at the molecular level, its role for the net photosynthesis (carbon assimilation) and transpiration (gas exchange) rate is currently unknown.
Objectives of this study are to (1) quantify radial growth of the two common European tree species, Scots pine and oak along a latitudinal gradient from southern Spain to northern Germany with particular focus on the effects of extreme events, and (2) quantify the potential role of epigenetic effects on seed germination, seedling establishment and survival in variable growing conditions (water, temperature and shading).
Objective-1: Tree-growth responses to extreme drought
Scots pine
615 adult Scots pine trees from 30 sites along an approximately 2800 km long latitudinal gradient from southern Spain (Baza; 37.2° N, 4.0º W) to north-eastern Germany (Torgelow; 53.6 °N, 14° W) was used.
For tree growth resilience, we computed three resilience indices as suggested by Lloret et al. (2011): resistance, recovery, and resilience. The resistance quantifies the ratio between growth during a drought period and growth during the preceding non-drought period, representing thus the capacity of the trees to buffer the stress and maintain growth during drought. The recovery quantifies the growth reaction following the drought period and is defined by the ratio between growth during the post-drought period and growth during the drought period. The resilience quantifies the ratio between growth during the post-drought period and growth during the pre-drought period, which represents the capacity of trees to recover and regain the growth of the pre-drought period.
615 adult Scots pine trees from 30 sites along an approximately 2800 km long latitudinal gradient from southern Spain (Baza; 37.2° N, 4.0º W) to north-eastern Germany (Torgelow; 53.6 °N, 14° W) was used.
For tree growth resilience, we computed three resilience indices as suggested by Lloret et al. (2011): resistance, recovery, and resilience. The resistance quantifies the ratio between growth during a drought period and growth during the preceding non-drought period, representing thus the capacity of the trees to buffer the stress and maintain growth during drought. The recovery quantifies the growth reaction following the drought period and is defined by the ratio between growth during the post-drought period and growth during the drought period. The resilience quantifies the ratio between growth during the post-drought period and growth during the pre-drought period, which represents the capacity of trees to recover and regain the growth of the pre-drought period.
Oak species
1310, 154, and 597 trees of Quercus petraea, Quercus pubescens, and Quercus robur, respectively from 119 sites along an approximately 2000 km long latitudinal gradient from norther Spain (40.2° N, 1.8º E) to north-eastern Germany (Torgelow; 53.6 °N, 14° W) was used.
Similar to Scots pine, tree growth resistance, recovery, and resilience to extreme drought was assessed and the influence of legacy effects of drought to the growth of post-drought years were examined.
1310, 154, and 597 trees of Quercus petraea, Quercus pubescens, and Quercus robur, respectively from 119 sites along an approximately 2000 km long latitudinal gradient from norther Spain (40.2° N, 1.8º E) to north-eastern Germany (Torgelow; 53.6 °N, 14° W) was used.
Similar to Scots pine, tree growth resistance, recovery, and resilience to extreme drought was assessed and the influence of legacy effects of drought to the growth of post-drought years were examined.
Objective-2: Transgenerational acclimation in Scots pine
In order to disentangle drought-induced parental legacy effects, legacy effects of irrigation on soil properties, and direct environmental drivers on seed and seedling performance, we carried out two offspring establishment experiments, one at the experimental site in Pfynwald (referred to as "field") and another under controlled environmental conditions in the greenhouse at the Swiss Federal Research Institute WSL (“greenhouse”).
In the greenhouse, the offspring from control trees exposed regularly to drought were more tolerant to hot-drought conditions than the offspring from irrigated trees and showed lower mortality even though there was no genetic difference. However, under optimal conditions (high water supply and full sunlight) these offspring showed lower growth and were outperformed by the offspring of the irrigated trees. This different offspring growth, with the offspring of the “irrigation-stop” trees showing intermediate responses, points to the important role of transgenerational memory for the long-term acclimation of trees. Such memory effects, however, may be overridden by climatic extremes during germination and early growth stages such as the European 2018 mega-drought that impacted our field experiment.
Published in the journal Plant, Cell & Environment.
In the greenhouse, the offspring from control trees exposed regularly to drought were more tolerant to hot-drought conditions than the offspring from irrigated trees and showed lower mortality even though there was no genetic difference. However, under optimal conditions (high water supply and full sunlight) these offspring showed lower growth and were outperformed by the offspring of the irrigated trees. This different offspring growth, with the offspring of the “irrigation-stop” trees showing intermediate responses, points to the important role of transgenerational memory for the long-term acclimation of trees. Such memory effects, however, may be overridden by climatic extremes during germination and early growth stages such as the European 2018 mega-drought that impacted our field experiment.
Published in the journal Plant, Cell & Environment.