scholarly journals Impact of summer drought on isoprenoid emissions and carbon sink of three Scots pine provenances

2017 ◽  
Vol 37 (6) ◽  
pp. 846-846
Author(s):  
M. Lüpke ◽  
M. Leuchner ◽  
R. Steinbrecher ◽  
A. Menzel
Keyword(s):  
Scots Pine ◽  
Carbon Sink ◽  
Summer Drought ◽  
Isoprenoid Emissions

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 Modelling short-term variability in carbon and water exchange in a temperate Scots pine forest

2015 ◽  
Vol 6 (2) ◽  
pp. 485-503 ◽  
Author(s):  
M. H. Vermeulen ◽  
B. J. Kruijt ◽  
T. Hickler ◽  
P. Kabat
Keyword(s):  
Water Uptake ◽  
Scots Pine ◽  
Water Exchange ◽  
Carbon Sink ◽  
Pine Forest ◽  
Temperature Threshold ◽  
Water Fluxes ◽  
Local Data ◽  
Deep Soil ◽  
Scots Pine Forest

Abstract. The vegetation–atmosphere carbon and water exchange at one particular site can strongly vary from year to year, and understanding this interannual variability in carbon and water exchange (IAVcw) is a critical factor in projecting future ecosystem changes. However, the mechanisms driving this IAVcw are not well understood. We used data on carbon and water fluxes from a multi-year eddy covariance study (1997–2009) in a Dutch Scots pine forest and forced a process-based ecosystem model (Lund–Potsdam–Jena General Ecosystem Simulator; LPJ-GUESS) with local data to, firstly, test whether the model can explain IAVcw and seasonal carbon and water exchange from direct environmental factors only. Initial model runs showed low correlations with estimated annual gross primary productivity (GPP) and annual actual evapotranspiration (AET), while monthly and daily fluxes showed high correlations. The model underestimated GPP and AET during winter and drought events. Secondly, we adapted the temperature inhibition function of photosynthesis to account for the observation that at this particular site, trees continue to assimilate at very low atmospheric temperatures (up to daily averages of −10 °C), resulting in a net carbon sink in winter. While we were able to improve daily and monthly simulations during winter by lowering the modelled minimum temperature threshold for photosynthesis, this did not increase explained IAVcw at the site. Thirdly, we implemented three alternative hypotheses concerning water uptake by plants in order to test which one best corresponds with the data. In particular, we analyse the effects during the 2003 heatwave. These simulations revealed a strong sensitivity of the modelled fluxes during dry and warm conditions, but no single formulation was consistently superior in reproducing the data for all timescales and the overall model–data match for IAVcw could not be improved. Most probably access to deep soil water leads to higher AET and GPP simulated during the heatwave of 2003. We conclude that photosynthesis at lower temperatures than assumed in most models can be important for winter carbon and water fluxes in pine forests. Furthermore, details of the model representations of water uptake, which are often overlooked, need further attention, and deep water access should be treated explicitly.

The future of cool temperate bogs

2002 ◽  
Vol 29 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Peter D. Moore
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Sink ◽  
Western World ◽  
Summer Drought ◽  
Oxidation Of Methane ◽  
Living Things ◽  
The Future ◽  
Atmospheric Carbon ◽  
Carbon Dioxide Levels

The temperate peatlands are extensive, covering around 3.5 million km2 of land. They contain about 455 Gt of carbon, almost equivalent to the carbon stored in all of the living things on the surface of the planet, and representing around 25% of all the soil carbon on earth. These bogs are a sink for atmospheric carbon and their carbon uptake accounts for about 12% of current human emissions. They vary considerably in their form and structure and are an important resource for scientific research, including the study of past environments and climate change, and they are also valuable in environmental education. They are low in biodiversity, but their fauna and flora are distinctive and many groups are confined to this habitat. For all these reasons, the future conservation of peatlands is a matter for concern. Threats to peatlands come from direct human exploitation in the form of peat harvesting for energy and horticulture, and drainage for forestry. Rising environmental awareness should control both of these processes in the western world, but continued northern peatland losses are likely locally, especially in Asia. Peatland drainage for forestry or agriculture will result in losses of carbon to the atmosphere, adding to the greenhouse effect. Human population pressures, industrialization and urbanization are unlikely to have an important direct and immediate influence in the boreal zone. Fragmentation of the habitat is not an important consideration because bogs are by their very nature ‘island’ habitats. Acidification by aerial pollution may be a local problem close to sources, but the habitat is naturally acid and should not be severely affected. The input of aerial nutrients, however, particularly nitrogen, could have widespread impact on bogs, enhancing their productivity and altering their vegetation composition. The physical rehabilitation of bogs damaged by human activities presents many problems, particularly relating to the re-establishment of peat structure and vegetation, but the process can result in the re-formation of a carbon sink so it is worth the effort. Climate change is the most important consideration in its impact on bogs. Higher temperature (especially if accompanied by raised atmospheric carbon dioxide levels and increased nitrate deposition) will enhance productivity, but will also result in faster decomposition rates. The outcome of these opposing factors for peat formation will ultimately depend on the future pattern of precipitation. If, as seems most likely, summer conditions become warmer and drier in continental regions and winters become milder and wetter, the summer drought could cause peat loss and bog contraction. An excess of decomposition will lead to bogs becoming a carbon source and thus a positive feedback in global warming. Emissions of methane and nitrous oxide would add to the greenhouse gas problem, but likely oxidation of methane and low N2O production may well mean that this impact will not prove to be significant. Tree invasion of bogs as a consequence of summer drought could locally lead to increased water loss through transpiration, and higher heat absorption through albedo change. This will enhance the drying effect on the bog surface. Oceanic mires will be less severely affected if the expected increase in precipitation takes place in these regions. The most important overall factor in determining the future of the northern bogs is likely to be the quantity and pattern (both spatially and temporally) of future precipitation in the zone.

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 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.

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