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

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.

Download Full-text

Patterns of mast fruiting of common beech, sessile and common oak, Norway spruce and Scots pine in Central and Northern Europe

Forest Ecology and Management ◽

10.1016/j.foreco.2015.12.033 ◽

2016 ◽

Vol 363 ◽

pp. 237-251 ◽

Cited By ~ 29

Author(s):

Anita Nussbaumer ◽

Peter Waldner ◽

Sophia Etzold ◽

Arthur Gessler ◽

Sue Benham ◽

...

Keyword(s):

Norway Spruce ◽

Scots Pine ◽

Northern Europe ◽

Common Beech ◽

Mast Fruiting ◽

Common Oak

Download Full-text

Growth Responses of Boreal Scots Pine, Norway Spruce and Silver Birch Seedlings to Simulated Climate Warming over Three Growing Seasons in a Controlled Field Experiment

Forests ◽

10.3390/f11090943 ◽

2020 ◽

Vol 11 (9) ◽

pp. 943

Author(s):

Katri Nissinen ◽

Virpi Virjamo ◽

Antti Kilpeläinen ◽

Veli-Pekka Ikonen ◽

Laura Pikkarainen ◽

...

Keyword(s):

Norway Spruce ◽

Scots Pine ◽

Root Biomass ◽

Growing Season ◽

Silver Birch ◽

Shoot Biomass ◽

Growth Responses ◽

Growing Seasons ◽

Simulated Climate ◽

Shoot And Root Biomass

We studied the growth responses of boreal Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and silver birch (Betula pendula Roth) seedlings to simulated climate warming of an average of 1.3 °C over the growing season in a controlled field experiment in central Finland. We had six replicate plots for elevated and ambient temperature for each tree species. The warming treatment lasted for the conifers for three growing seasons and for the birch two growing seasons. We measured the height and diameter growth of all the seedlings weekly during the growing season. The shoot and root biomass and their ratios were measured annually in one-third of seedlings harvested from each plot in autumn. After two growing seasons, the height, diameter and shoot biomass were 45%, 19% and 41% larger in silver birch seedlings under the warming treatment, but the root biomass was clearly less affected. After three growing seasons, the height, diameter, shoot and root biomass were under a warming treatment 39, 47, 189 and 113% greater in Scots pine, but the root:shoot ratio 29% lower, respectively. The corresponding responses of Norway spruce to warming were clearly smaller (e.g., shoot biomass 46% higher under a warming treatment). As a comparison, the relative response of height growth in silver birch was after two growing seasons equal to that measured in Scots pine after three growing seasons. Based on our findings, especially silver birch seedlings, but also Scots pine seedlings benefitted from warming, which should be taken into account in forest regeneration in the future.

Download Full-text