Modeling the forest phosphorus nutrition in a southwestern Swedish forest site
Introduction
Forests are among the most important ecosystems on the planet, providing and regulating multiple important services such as timber production, biodiversity conservation, carbon (C) sequestration, bioenergy supply and potable water supply (Nelson et al., 2011; COM, 2013). Nitrogen (N) is often reported to limit growth in northern forest ecosystems (Tamm, 1991; Jonard et al., 2015). The increase in atmospheric N deposition due to anthropogenic activities has shifted forest ecosystems from being N-limited towards being N-saturated (Aber et al., 1989; Aber et al., 1998), causing N leaching in some forest ecosystems (Gundersen et al., 2006; Kreutzer et al., 2009; Yu et al., 2016). An increased nitrogen pool in the forest can affect other nutrient pools and thereby forest nutrition. It can compromise the availability of base cations by depleting soil base cations through N leaching, which causes acidification and eutrophication (Driscoll et al., 2003; Eriksson et al., 1992; Likens et al., 1996). Another effect of increased N status is a stimulated forest growth (Reich et al., 2006; Ciais et al., 2013), leading to the limitation of other nutrients such as phosphorus (P) (Aber et al., 1989; Akselsson et al., 2008). A switch from N limitation to P limitation over recent decades has been found in many forest studies and experimental studies in Europe (Braun et al., 2010; Jonard et al., 2015; Talkner et al., 2015; Flückiger and Braun, 1999) and North America (Crowley et al., 2012; Tessier and Raynal, 2003; Gress et al., 2007). Such a transition, from N limitation to P limitation, is not commonly detected in Swedish forests (Ingerslev et al., 2001; Högberg et al., 2006) due to the generally relatively low atmospheric N deposition in Sweden (Simpson et al., 2011). However, in southwestern Sweden, where current and historical N deposition is highest (Akselsson et al., 2010), it is suspected that P limitation might already occur (Rosengren-Brinck and Nihlgård, 1995; Akselsson et al., 2008).
Forest P limitation has long been evaluated by the needle N/P ratio (Linder, 1995; Rosengren-Brinck and Nihlgård, 1995; Mellert and Göttlein, 2012; Jonard et al., 2015; Braun et al., 2010), partly because foliar nutrient concentrations and ratios are well-established indicators of nutrient limitation in forest trees (Mellert and Ewald, 2014; Jonard et al., 2015). Particularly because P nutrition in forests is more challenging to evaluate than other nutrients, due to the high uncertainties in quantifying the biogeochemical P processes (Frossard et al., 2011; Shen et al., 2011; Fox et al., 2011; Jones and Oburger, 2011), and measuring the soil P availability (Shen et al., 2011; Hinsinger, 2001). Due to the high uncertainties in P processes measurement, the forest P cycle has not been much quantitatively investigated in field studies (Yanai, 1992; Yanai, 1998; Jonard et al., 2009), nor has it been soundly evaluated in modeling studies (Jonard et al., 2010; Achat et al., 2009; Wang et al., 2010; Yang et al., 2014; Müller and Bünemann, 2014). These highly uncertain P processes include atmospheric deposition (Newman, 1995; Tipping et al., 2014), weathering (Newman, 1995; Smits et al., 2012), sorption/desorption (McGechan and Lewis, 2002; Frossard et al., 2011), mineralization (Bünemann, 2015), and rhizosphere processes (Hinsinger, 2001; Hinsinger et al., 2011). Nevertheless, forest P cycle and its impacts on other cycles (e.g. C and N) are much less investigated in modeling studies simply due to the absence of P cycle in most forest/terrestrial ecosystem models (Fontes et al., 2010; Flato et al., 2013).
In this paper, we first implemented a P module, which contains the biogeochemical processes of the full P cycle, into the integrated dynamic forest model, ForSAFE. We then tested the model at a southwestern Swedish forest site, which is at high risk of P limitation. The aims of this study were: 1) to evaluate the forest nutrition (N and P) at the study site, 2) to quantify the forest P cycle, especially the biogeochemical P processes, from a modeling perspective.
Section snippets
The ForSAFE model
ForSAFE is a mechanistic biogeochemical model of the forest ecosystem and was designed to simulate the dynamic responses of the forest ecosystem to environmental changes (Zanchi et al., 2014; Yu et al., 2016). The model aggregates independent processes—chemical, physical, and physiological—based on empirical evidence (Belyazid, 2006; Wallman et al., 2005). These independent but mutually interacting processes bring together three basic material and energy cycles to form a single integrated
Model evaluation
The model overestimated the wood biomass by 17% and underestimated the foliage biomass by 13%, but the modeled trends for the change in wood biomass and leaf biomass agreed well with the measurements (Fig. 3). The modeled needle N concentrations were about 5% lower than the forest inventory data. Although less noticeable, the model still captured the decrease in needle N concentration after 2000. The modeled needle P concentrations were within the range of the forest inventory data, but the
Forest nutrition at the study site
Swedish forests are mostly limited by N due to low N deposition (Akselsson et al., 2007; Akselsson et al., 2008). Previous forest studies in Sweden have shown that Swedish forests usually have either relatively high needle P concentrations (Vestin et al., 2013; Rothpfeffer and Karltun, 2007) or low needle N/P ratios due to very low needle N concentrations (Bauer et al., 1997; Anonymous, 2003). However, low needle P concentrations or high needle N/P ratios (>10) have been reported in southern
Conclusions
The ForSAFE model was implemented with a P module containing the biogeochemical P cycle and tested at Klintaskogen forest site. Both the forest inventory data and the model results supported the suspicion that Klintaskogen is already limited by P. The model simulations showed that between1900 and 2000 the site switched from being N-limited to being P-limited, and in future the site may return to N limitation, however, this prediction is heavily dependent on the low future projection of N
Acknowledgments
The authors wish to express their gratitude for the financial support granted by the project “Biodiversity and Ecosystem services in a Changing Climate” (BECC). We also thank Gregory van der Heijden, Nicholas Rosenstock, Ann-Mari Fransson, Christian Morel and Pål Axel Olsson for their valuable advice on model development.
References (100)
Long-term organic phosphorus mineralization in Spodosols under forests and its relation to carbon and nitrogen mineralization
Soil Biol. Biochem.
(2010)Logging residue harvest may decrease enzymatic activity of boreal forest soils
Soil Biol. Biochem.
(2015)Contribution of sorption: DOC transport and microbial interactions to the 14C age of a soil organic carbon profile: insights from a calibrated process model
Soil Biol. Biochem.
(2015)Nutrient and carbon budgets in forest soils as decision support in sustainable forest management
For. Ecol. Manage.
(2007)The influence of N load and harvest intensity on the risk of P limitation in Swedish forest soils
Sci. Total Environ.
(2008)Assessing the risk of N leaching from forest soils across a steep N deposition gradient in Sweden
Environ. Pollut.
(2010)Soil biology & biochemistry assessment of gross and net mineralization rates of soil organic phosphorus: A review
Soil Biol. Biochem.
(2015)Does nitrogen deposition increase forest production? The role of phosphorus
Environ. Pollut.
(2010)The role of sensitivity analysis in ecological modelling
Ecol. Modell.
(2007)- et al.
A literature review and evaluation of the: hedley fractionation: applications to the biogeochemical cycle of soil phosphorus in natural ecosystems
Geoderma
(1995)
Effects of acidic deposition on forest and aquatic ecosystems in New York State
Environ. Pollut.
Modeling forest floor contribution to phosphorus supply to maritime pine seedlings in two-layered forest soils
Ecol. Modell.
A 33P tracing model for quantifying gross P transformation rates in soil
Soil Biol. Biochem.
Soil carbon and nitrogen mineralization: theory and models across scales
Soil Biol. Biochem.
Sorption of phosphorus by soil, part 1: principles, equations and models
Biosyst. Eng.
Comparative aspects of cycling of organic C, N, S and P through soil organic matter
Geoderma
Inorganic elements in tree compartments of Picea abies-Concentrations versus stem diameter in wood and bark and concentrations in needles and branches
Biomass Bioenergy
Hydrologic controls on phosphorus dynamics: a modeling framework
Adv. Water Resour.
The implications of exoenzyme activity on microbial carbon and nitrogen limitation in soil: a theoretical model
Soil Biol. Biochem.
Dynamics of diffusive soil phosphorus in two grassland experiments determined both in field and laboratory conditions Agriculture
Ecosyst. Environ.
The stimulating effect of apatite on ectomycorrhizal growth diminishes after PK fertilization
Soil Biol. Biochem.
ForSAFE—an integrated process-oriented forest model for long-term sustainability assessments
For. Ecol. Manage.
DECOMP –a semi-mechanistic model of litter decomposition
Environ. Modell. Softw
Small-scale spatial distribution of phosphorus fractions in soils from silicate parent material with different degree of podzolization
Geoderma
The effect of whole-tree harvest on phosphorus cycling in a northern hardwood forest
For. Ecol. Manage.
Storm disturbances in a Swedish forest-A case study comparing monitoring and modelling
Ecol. Modell.
Modelling the effects of management intensification on multiple forest services: a Swedish case study
Ecol. Modell.
A generalized, lumped-parameter model of photosynthesis, evaporation and net primary production in temperate and boreal forest ecosystems
Oecologia
Nitrogen saturation in northern forest ecosystems
Bioscience
Nitrogen saturation in temperate forest ecosystems − Hypotheses revisited
Bioscience
Process-Based assessment of phosphorus availability in a low phosphorus sorbing forest soil using isotopic dilution methods
Soil Sci. Soc. Am. J.
Dynamics of Forest Soil Chemistry
Nutrient cycling in forests
New Phytol.
Nutrient contents and concentrations in relation to growth of Picea abies and Fagus sylvatica along a European transect
Tree Physiol.
Dynamic Modelling of Biogeochemical Processes in Forest Ecosystems
Plant Litter: Decomposition, Humus Formation, Carbon Sequestration
Carbon and other biogeochemical cycles
C:N:P stoichiometry in soil: is there a redfield ratio for the microbial biomass?
Biogeochemistry
Do nutrient limitation patterns shift from nitrogen toward phosphorus with increasing nitrogen deposition across the northeastern United States?
Ecosystems
Concentrations of mineral nutrients and arginine in needles of Picea abies trees from different areas in southern Sweden in relation to nitrogen deposition and humus form
Ecol. Bull.
Acidification of in Sweden forest
Ambio
Dynamics of phosphate in soils: an isotopic outlook
Fertil. Res.
Forest Condition in Europe 2011 Technical Report of ICP Forests and FutMon
Nitrogen and its effect on growth, nutrient status and parasite attacks in beech and Norway spruce
Water Air Soil Pollut.
Evaluation of climate models
Package QuantPsyc.
Models for supporting forest management in a changing environment
Forest Systems
The global nitrogen cycle in the twenty-first century
Philos. Trans. R. Soc. B
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