Tree mineral nutrition is deteriorating in Europe

Abstract

The response of forest ecosystems to increased atmospheric CO2 is constrained by nutrient availability. It is thus crucial to account for nutrient limitation when studying the forest response to climate change. The objectives of this study were to describe the nutritional status of the main European tree species, to identify growth-limiting nutrients and to assess changes in tree nutrition during the past two decades. We analysed the foliar nutrition data collected during 1992-2009 on the intensive forest monitoring plots of the ICP Forests programme. Of the 22 significant temporal trends that were observed in foliar nutrient concentrations, 20 were decreasing and two were increasing. Some of these trends were alarming, among which the foliar P concentration in F. sylvatica, Q. Petraea and P. sylvestris that significantly deteriorated during 1992-2009. In Q. Petraea and P. sylvestris, the decrease in foliar P concentration was more pronounced on plots with low foliar P status, meaning that trees with latent P deficiency could become deficient in the near future. Increased tree productivity, possibly resulting from high N deposition and from the global increase in atmospheric CO2, has led to higher nutrient demand by trees. As the soil nutrient supply was not always sufficient to meet the demands of faster growing trees, this could partly explain the deterioration of tree mineral nutrition. The results suggest that when evaluating forest carbon storage capacity and when planning to reduce CO2 emissions by increasing use of wood biomass for bioenergy, it is crucial that nutrient limitations for forest growth are considered.

Changes in the nutrition and health status of young Norway spruce stands in the Krkonoše Mts. in a 17-year period

“…Thereby the N/Mg ratio was thus consistently decreasing. Similar findings in regard to the temporal trends of N/K, N/Ca (an increase) and N/Mg (a decrease) ratios were reported by Jonard et al (2015) while the positive change in the foliar Mg concentration was more marked in plots with a low foliar Mg status. These trends of base cations are somewhat contradictory.…”

“…Phosphorus deficiency as a limiting factor in regard to the forest growth in the Bavarian Alps was reported by Mellert and Ewald (2014) regarding Norway spruce and by Ewald (2000) regarding European beech. Talkner et al (2014) documented a significant decrease of phosphorus nutrition throughout the beech stands in Europe which was also supported in other species by findings of Jonard et al (2015), who suggested the increased growth resulting from a high level of N deposition and from the global increase of atmospheric CO 2 as being the main driver behind the deterioration of mineral nutrition of trees. This conclusion can be supported by the significant increase of N/P ratio in both needle classes -though it is still within the optimal range (6-12) -indicating decreasing availability and possibly a nutritional imbalance of phosphorus in rela-tion to nitrogen uptake (Hüttl 1990;Drenowsky, Richards 2004;Luyssaert 2004;Ewald 2005).…”

Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

“…The tendency towards less favourable foliage nutrition at plots with high N concentration in soil solution is in line with our second hypothesis that the exceedance of critical limits affects the nutritional status of trees. It remains to be investigated whether the temporal trends of mineral nutrition in foliage determined by Jonard et al (2015) could be explained by changes in N deposition or N concentrations in soil solution.…”

Spatial Patterns of Phosphorus Fractions in Soils of Temperate Forest Ecosystems with Silicate Parent Material

“…Even though many soils in central Europe are young, the P status of forests is often low or insufficient (Ilg et al, 2009;Jonard et al, 2015). Soil acidification and N eutrophication, intensified by anthropogenic deposits, additionally reduces plant available P (Mohren et 5 al., 1986).…”