scholarly journals Close and distant: Contrasting the metabolism of two closely related subspecies of Scots pine under the effects of folivory and summer drought

2017 ◽  
Vol 7 (21) ◽  
pp. 8976-8988 ◽  
Author(s):  
Albert Rivas-Ubach ◽  
Jordi Sardans ◽  
José Antonio Hódar ◽  
Joan Garcia-Porta ◽  
Alex Guenther ◽  
...  
Keyword(s):  
Scots Pine ◽  
Summer Drought

scholarly journals Föhrenverjüngung: Plastizität und Akklimatisation in einem trockeneren Klima

2018 ◽  
Vol 169 (5) ◽  
pp. 269-278
Author(s):  
Barbara Moser ◽  
Christoph Bachofen ◽  
Thomas Wohlgemuth
Keyword(s):  
Scots Pine ◽  
Natural Regeneration ◽  
Common Garden ◽  
Forest Steppe ◽  
Short Time Scale ◽  
Summer Drought ◽  
Spring Precipitation ◽  
Pine Regeneration ◽  
A Minor ◽  
Rhone Valley

Pine regeneration: plasticity and acclimation in a dryer climate Increasing summer drought might limit the natural regeneration of Scots pine stands at low elevations of the Rhone valley. Common garden experiments at the forest-steppe ecotone have shown that emergence and establishment of Scots pine primarily depend on spring precipitation and, to a minor degree, on summer drought and rising temperatures. Scots pine seedlings acclimated rapidly to drought periods by favouring root to shoot growth. In the second year, the saplings were already adapted to drought so that most of them survived an extended spring and summer drought, as recorded at Sion twelve times during the last 154 years. Only an extreme summer drought – no water from June to September – killed 14.7% of the Scots pine saplings. Surprisingly, they were even able to acclimate to such extreme drought events: after the same extreme summer drought in the third year, mortality dropped below 5%. In general, the Scots pine was very plastic, i.e. seedlings and saplings changed their phenotype depending on environmental conditions. But we also found genetic adaptation: Scots pine originating from regions with pronounced summer drought, including populations from lower elevations in the Rhone valley, produced more biomass than those from moister regions in all treatment combinations. Black pine reacted similarly to the treatments like Scots pine, but it grew faster and more saplings survived the first extreme summer drought. These results show that Scots pine from low elevations of the Rhone valley is one of the most drought-tolerant provenances in Europe. Thanks to its high phenotypic plasticity and the ability of seedlings and saplings to acclimate to drought on a short time scale, natural regeneration of Scot pine at low elevations of the Rhone valley is likely to occur also under future conditions, but maybe less frequent than today.

scholarly journals Verjüngungspotenzial verschiedener Waldföhrenund Fichtenherkünfte bei variabler Trockenheit

2015 ◽  
Vol 166 (6) ◽  
pp. 399-407 ◽  
Author(s):  
Barbara Moser ◽  
Marek Metslaid ◽  
Lorenz Walthert ◽  
Ulrich Wasem ◽  
Thomas Wohlgemuth
Keyword(s):  
Water Balance ◽  
Norway Spruce ◽  
Scots Pine ◽  
Weather Conditions ◽  
Climatic Conditions ◽  
Water Retention Capacity ◽  
Summer Drought ◽  
Retention Capacity ◽  
Rhine Valley ◽  
A Minor

Regeneration potential of different Scots pine and Norway spruce provenances under variable drought Rising temperatures will lead to extended periods of summer drought, which may challenge the persistence of Scots pine and Norway spruce in dry alpine valleys where these species play an important role in the protection against natural hazards. We tested whether the natural regeneration of the two species in the Rhine valley near Chur, Switzerland, might be limited under future climatic conditions and we compared the performance of autochthonous provenances with that of seedlings originating from regions with already drier summer climate such as the Rhone valley, continental Eastern Europe or the Mediterranean basin. Seeds of Scots pine and Norway spruce were sown repeatedly in forest clearings at three south-exposed sites in the Rhine valley near Chur, Switzerland. Soil moisture was manipulated to a minor extent with throughfall reduction roofs. In both species, regeneration success was primarily driven by the weather conditions during the three months following seed sowing: the seedlings having emerged in the rainy spring of 2013 had a higher survival rate and accumulated up to five times more aboveground biomass than the seedlings emerging in the dry spring of 2011. In years with an average or even positive water balance, Scots pine seedlings were able to establish at all sites. In Norway spruce, by contrast, establishment rate exceeded 10% of viable seeds only at the site with the highest water retention capacity. In years with a positive water balance during spring, the seedlings from the Rhine and Rhone valleys outperformed those from most Mediterranean and Eastern European provenances, while no differences between provenances were found in the dry spring of 2011. We suggest that periodical regeneration of Scots pine will be likely in the Rhine valley even under future climatic conditions, whereas the establishment of Norway spruce may remain an exceptional event in dry, south-exposed clearings.

scholarly journals Temperature and moisture dependence of daily growth of Scots pine (Pinus sylvestris L.) roots in Southern Finland

2019 ◽  
Vol 40 (2) ◽  
pp. 272-283
Author(s):  
Yiyang Ding ◽  
Pauliina Schiestl-Aalto ◽  
Heljä-Sisko Helmisaari ◽  
Naoki Makita ◽  
Kira Ryhti ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Growth Patterns ◽  
Root Production ◽  
Summer Drought ◽  
Daily Growth ◽  
Drought Effect ◽  
Fibrous Roots ◽  
Root Types

Abstract Scots pine (Pinus sylvestris L.) is one of the most important conifers in Northern Europe. In boreal forests, over one-third of net primary production is allocated to roots. Pioneer roots expand the horizontal and vertical root systems and transport nutrients and water from belowground to aboveground. Fibrous roots, often colonized by mycorrhiza, emerge from the pioneer roots and absorb water and nutrients from the soil. In this study, we installed three flatbed scanners to detect the daily growth of both pioneer and fibrous roots of Scots pine during the growing season of 2018, a year with an unexpected summer drought in Southern Finland. The growth rate of both types of roots had a positive relationship with temperature. However, the relations between root elongation rate and soil moisture differed significantly between scanners and between root types indicating spatial heterogeneity in soil moisture. The pioneer roots were more tolerant to severe environmental conditions than the fibrous roots. The pioneer roots initiated elongation earlier and ceased it later than the fibrous roots. Elongation ended when the temperature dropped below the threshold temperature of 4 °C for pioneer roots and 6 °C for fibrous roots. During the summer drought, the fibrous roots halted root surface area growth at the beginning of the drought, but there was no drought effect on the pioneer roots over the same period. To compare the timing of root production and the aboveground organs’ production, we used the CASSIA model, which estimates the aboveground tree carbon dynamics. In this study, root growth started and ceased later than growth of aboveground organs. Pioneer roots accounted for 87% of total root productivity. We suggest that future carbon allocation models should separate the roots by root types (pioneer and fibrous), as their growth patterns are different and they have different reactions to changes in the soil environment.

scholarly journals Assessing urban climate effects on Pinus sylvestris with point dendrometers: a case study from Stockholm, Sweden

Trees ◽  
2021 ◽  
Author(s):  
Eva Rocha ◽  
Steffen Holzkämper
Keyword(s):  
High Resolution ◽  
Scots Pine ◽  
Urban Climate ◽  
Water Storage ◽  
Urban Trees ◽  
Summer Drought ◽  
Reference Period ◽  
Growth Responses ◽  
Pine Trees ◽  
The Impact

Abstract Key message Extreme drought conditions, in addition to the urban heat island effect, modify the growth response and water storage dynamics of urban Scots pine trees in the Stockholm region. Abstract Changes in surface properties of the urban environments significantly impact the local microclimate. While urban trees are known for providing important thermal regulation, the impact of urban climate on tree growth remains relatively unexplored. The present study focuses on the climate response and growth dynamics of urban Scots pine trees (P. sylvestris) in comparison to their rural counterparts. High-resolution monitoring of stem-radius variations using automatic point dendrometers was performed during the growing seasons (April–October) of 2017 and 2018 in Stockholm, Sweden. In 2018, the region experienced a severe and long-lasting summer drought. In May and July, temperatures were up to 5 °C higher relative to the reference period (1981–2010), and precipitation sums were below the reference period for the entire growing season. Our results show that the urban climate primarily impacts the daily water storage dynamics by decreasing the radius change amplitudes and delaying the time of maximum stem-water replenishment and depletion. Under standard climatic conditions, the warmer climate (1.3 °C) at the urban sites had a positive impact on radial growth increment. Drought periods significantly impact the climate–growth relationships. Stem shrinkage intensifies during the day, and lower growth rates were registered, resulting in reduced annual growth. The high-resolution monitoring provided valuable insights into daily and seasonal patterns of Scots pine stem-radius variations, showing that growth responses to increasing temperature are mainly controlled by moisture availability and site-specific conditions.

scholarly journals Response of water use efficiency to summer drought in boreal Scots pine forests in Finland

2016 ◽  
Author(s):  
Yao Gao ◽  
Tiina Markkanen ◽  
Mika Aurela ◽  
Ivan Mammarella ◽  
Tea Thum ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Use Efficiency ◽  
Water Use ◽  
Time Scales ◽  
Scots Pine ◽  
Land Surface ◽  
Summer Drought ◽  
Ecosystem Level ◽  
Use Efficiency ◽  
Daily Time

Abstract. The influence of drought on plant functioning has received considerable attention in recent years, although our understanding of the response of carbon and water coupling in terrestrial ecosystems remains unclear. In this study, we investigated the response of water use efficiency to summer drought in boreal forests at daily time scales mainly using eddy covariance flux data. In addition, simulation results from the JSBACH land surface model were evaluated against the observed results. Two Scots pine (Pinus sylvestris) sites at Hyytiälä (southern Finland) and Sodankylä (northern Finland) were used in the study. Based on observed data, the ecosystem level water use efficiency (EWUE) showed a decrease only during a severe soil moisture drought at Hyytiälä, whereas the inherent water use efficiency (IWUE) increased when there was a severe soil moisture drought at Hyytiälä and a moderate soil moisture drought at Sodankylä. This indicates a decrease in surface conductance at the ecosystem level, but the decrease in evapotranspiration (ET) was alleviated because of the increased vapor pressure deficit (VPD) during drought. Moreover, the changes in IWUE implied that Scots pine has weaker response to drought in the southern site than in the northern site. Thus, IWUE is a more appropriate metric than EWUE for capturing the impact of soil moisture drought on plant functioning at daily time scales. In general, the results from transpiration based ecosystem level water use efficiency (EWUEt) and IWUE, and the transpiration based inherent water use efficiency (IWUEt) from JSBACH simulations were similar to the observed results. The deviated groups of gross primary production (GPP) and evapotranspiration (ET) under severe soil moisture drought in observed data at Hyytiälä were also successfully captured in the simulated results. However, deficiencies in the model were clearly seen by the limitation effect of air humidity on stomatal conductance in observed data. Our study provides a deeper understanding of carbon and water dynamics in the major boreal ecosystem. These findings highlight the importance of choosing a suitable plant functioning indicator when investigating the effects of drought, and suggest possible improvements to land surface models, which play an important role in the prediction of biosphere-atmosphere feedbacks in the climate system.

Size-dependent responses to summer drought in Scots pine, Norway spruce and common oak

Trees ◽  
2011 ◽  
Vol 26 (2) ◽  
pp. 557-569 ◽  
Author(s):  
Christian Zang ◽  
Hans Pretzsch ◽  
Andreas Rothe
Keyword(s):  
Norway Spruce ◽  
Scots Pine ◽  
Summer Drought ◽  
Size Dependent ◽  
Common Oak
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