Boreal Forest Research Articles

Benchmarking GOCART-2G in the Goddard Earth Observing System (GEOS)

Abstract. The Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, which controls the sources, sinks, and chemistry of aerosols within the Goddard Earth Observing System (GEOS), recently underwent a major refactoring and update, including a revision of the emissions datasets and the addition of brown carbon. A 4-year benchmark simulation utilizing the new version of the model code, termed GOCART Second Generation (GOCART-2G) and coupled to the Goddard Earth Observing System (GEOS) model, was evaluated using in situ and spaceborne measurements to develop a baseline and prioritize future development. A comparison of simulated aerosol optical depth between GOCART-2G and MODIS retrievals indicates the model captures the overall spatial pattern and seasonal cycle of aerosol optical depth but overestimates aerosol extinction over dusty regions and underestimates aerosol extinction over Northern Hemisphere boreal forests, requiring further investigation and tuning of emissions. This MODIS-based analysis is corroborated by comparisons to MISR and selected AERONET stations; however, discrepancies between the Aqua and Terra satellites indicate there is a diurnal component to biases in aerosol optical depth over southern Asia and northern Africa. Despite the underestimate of aerosol optical depth in biomass burning regions in GEOS, there is an overestimate in the surface mass of organic carbon in the United States, especially during the summer months. Over Europe, GOCART-2G is unable to match the summertime peak in aerosol optical depth, opposing the observed late fall and early spring peaks in surface mass concentration. A comparison of the vertical profile of attenuated backscatter to observations from CALIPSO indicates the GEOS model is capable of capturing the vertical profile of aerosol; however, the mid-troposphere plumes of dust in the North Atlantic and smoke in the southeastern Atlantic are perhaps too low in altitude. The results presented highlight priorities for future development with GOCART-2G, including improvements for dust, biomass burning aerosols, and anthropogenic aerosols.

Environmental drivers and cryptic biodiversity hotspots define endophytes in Earth’s largest terrestrial biome

Understanding how symbiotic associations differ across environmental gradients is key to predicting the fate of symbioses as environments change, and it is vital for detecting global reservoirs of symbiont biodiversity in a changing world.1,2,3 However, sampling of symbiotic partners at the full-biome scale is difficult and rare. As Earth's largest terrestrial biome, boreal forests influence carbon dynamics and climate regulation at a planetary scale. Plants and lichens in this biome host the highest known phylogenetic diversity of fungal endophytes, which occur within healthy photosynthetic tissues and can influence hosts' resilience to stress.4,5 We examined how communities of endophytes are structured across the climate gradient of the boreal biome, focusing on the dominant plant and lichen species occurring across the entire south-to-north span of the boreal zone in eastern North America. Although often invoked for understanding the distribution of biodiversity, neither a latitudinal gradient nor mid-domain effect5,6,7 can explain variation in endophyte diversity at this trans-biome scale. Instead, analyses considering shifts in forest characteristics, Picea biomass and age, and nutrients in host tissues from 46° to 58° N reveal strong and distinctive signatures of climate in defining endophyte assemblages in each host lineage. Host breadth of endophytes varies with climate factors, and biodiversity hotspots can be identified at plant-community transitions across the boreal zone at a global scale. Placed against a backdrop of global circumboreal sampling,4 our study reveals the sensitivity of endophytic fungi, their reservoirs of biodiversity, and their important symbiotic associations, to climate.

Climatic and management‐related drivers of endemic European spruce bark beetle populations in boreal forests

Abstract Climate change is already reducing carbon sequestration in Central European forests dramatically through extensive droughts and bark beetle outbreaks. Further warming may threaten the enormous carbon reservoirs in the boreal forests in northern Europe unless disturbance risks can be reduced by adaptive forest management. The European spruce bark beetle (Ips typographus) is a major natural disturbance agent in spruce‐dominated forests and can overwhelm the defences of healthy trees through pheromone‐coordinated mass‐attacks. We used an extensive dataset of bark beetle trap counts to quantify how climatic and management‐related factors influence bark beetle population sizes in boreal forests. Trap data were collected during a period without outbreaks and can thus identify mechanisms that drive populations towards outbreak thresholds. The most significant predictors of bark beetle population size were the volume of mature spruce, the extent of newly exposed clearcut edges, temperature and soil moisture. For clearcut edge, temperature and soil moisture, a 3‐year time lag produced the best model fit. We demonstrate how a model incorporating the most significant predictors, with a time lag, can be a useful management tool by allowing spatial prediction of future beetle population sizes. Synthesis and Applications: Some of the population drivers identified here, i,e., spruce volume and clearcut edges, can be targeted by adaptive management measures to reduce the risk of future bark beetle outbreaks. Implementing such measures may help preserve future carbon sequestration of European boreal forests.

Influence of Terrain Slope on Sub-Surface Fire Behavior in Boreal Forests of China

In recent years, the influence of extreme weather patterns has led to an alarming increase in the frequency and severity of sub-surface forest fires in boreal forests. The Ledum palustre-Larix gmelinii forests of the Daxing’an Mountains of China have emerged as a hotspot for sub-surface fires, and terrain slope has been recognized as a pivotal factor shaping forest fire behavior. The present study was conducted to (1) study the effect of terrain slope on the smoldering temperature and spread rate using simulated smoldering experiments and (2) establish occurrence probability prediction model of the sub-surface fires’ smoldering with different slopes based on the random forest model. The results showed that all the temperatures with different slopes were high, and the highest temperature was 947.91 °C. The spread rates in the horizontal direction were higher than those in the vertical direction, and the difference increased as the slope increased. The influence of slope on the peak temperature was greater than that of spread rate. The peak temperature was extremely positively correlated with the slope, horizontal distance and vertical depth. The spread rate was extremely positively correlated with the slope. The spread rate in the vertical direction was strongly positively correlated with the depth, but was strongly negatively correlated with the horizontal distance; the horizontal spread rate was opposite. The prediction equations for smoldering peak temperature and spread rate were established based on slope, horizontal distance, and vertical depth, and the model had a good fit (p < 0.01). Using random forest model, we established the occurrence prediction models for different slopes based on horizontal distance, vertical depth, and combustion time. The models had a good fit (AUC > 0.9) and high prediction accuracy (accuracy > 80%). The study proved the effect of slope on the characteristics of sub-surface fire smoldering, explained the variation in peak temperature and spread rate between different slopes, and established the occurrence prediction model based on the random forest model. The selected models had a good fit, and prediction accuracy met the requirement of the sub-surface fire prediction.

Drought response of the boreal forest carbon sink is driven by understorey–tree composition

The boreal forest is an important global carbon sink, but its response to drought remains uncertain. Here, we compiled biometric- and chamber-based flux data from 50 boreal forest stands to assess the impact of the 2018 European summer drought on net ecosystem production (NEP) across a 68 km2 managed landscape in northern Sweden. Our results reveal a non-uniform reduction in NEP (on average by 80 ± 16 g C m−2 yr−1 or 57 ± 13%) across the landscape, which was greatest in young stands of 20–50 years (95 ± 39 g C m−2 yr−1), but gradually decreased towards older stands (54 ± 57 g C m−2 yr−1). This pattern was attributed to the higher sensitivity of forest-floor understorey to drought and its decreasing contribution to production relative to trees during stand development. This suggests that an age-dependent shift in understorey–tree composition with increasing stand age drives the drought response of the boreal forest NEP. Thus, our study advocates the need for partitioning ecosystem responses to improve empirical and modelling assessments of carbon cycle–climate feedbacks in boreal forests. It further implies that the forest age structure may strongly determine the carbon sink response to the projected increase in drought events across the managed boreal landscape.

Arriving at a tipping point for worldwide forest decline due to accelerating climatic change

The 2023–2024 El Niño is inducing an acceleration of global warming that is likely to far exceed 1.5 °C. The Boreal summer of 2023 provided numerous examples of catastrophic forest fires (e.g., >18 million hectares of forest burned in Canada, making the Canadian forest a clear carbon source rather than a carbon sink), a trend that has been accompanied by worldwide examples of unusual tree mortality linked to hotter droughts. It is reasonable to expect that the warming induced by El Niño could push forests in several parts of the world over a tipping point, where they will hardly be able to recover their original state. It is therefore necessary to address the meaning, realistically, of sustainable forest management in the era of accelerated climatic change. The ultimate goal of the broadly accepted silvicultural practice of maintaining forests in a state that resembles what we recognize as temperate or boreal forests is becoming more of an idealistic dream rather than an attainable goal. Thus, the time has arrived to discuss painful forest management decisions, such as anticipated thinning to reduce water competition and the gradual replacement of native local forest populations with more drought-resistant provenances and species.

Response of Boreal Plant Communities and Forest Floor Carbon Fluxes to Experimental Nutrient Additions

Response of Boreal Plant Communities and Forest Floor Carbon Fluxes to Experimental Nutrient Additions

The Effect of Climate Change on Forest Fire Danger and Severity in the Canadian Boreal Forests for the Period 1976–2100

AbstractRecent climatic trends have increased forest fire activity in Canada. This study aimed to evaluate how forest fire conditions might evolve across the Canadian boreal forests in the future and to inform discussions about the impact of climate change on fire danger and severity. I generated surfaces of daily climate conditions using daily observational data from meteorological stations across Canada from 1976 to 2014. Simulated daily values of the same climatic variables were obtained from four earth system models of the Coupled Model Intercomparison Project Phase 5 project (CMIP5) for the historical period 1976–2005. Daily climate values for 2006–2100, forced by three climate change scenarios, Representative Concentration Pathway (RCP) 2.6, RCP 4.5, and RCP 8.5, were also simulated by the models. The simulated data were bias‐corrected and delta‐downscaled to project future trends in fire activity to assess the spatiotemporal variations of the potential impacts of climate change on forest fires. My results suggest fire danger and severity would increase in many Canadian boreal forests under RCP 8.5. The changes in fire conditions under RCP 2.6 were the least noteworthy; RCP 4.5 was associated with medium‐level changes.

A bootstrap-based approach to combine individual-based forest growth models and remotely sensed data

Abstract Combining forest growth models with remotely sensed data is possible under a generalized hierarchical model-based (GHMB) inferential framework. This implies the existence of two submodels: the growth model itself ($\mathcal{M}_{1}$) and a second submodel that links the growth predictions to some remotely sensed variables ($\mathcal{M}_{2}$). Analytical GHMB estimators are available to fit submodel $\mathcal{M}_{2}$ and account for the uncertainty stemming from submodel $\mathcal{M}_{1}$, i.e. the growth model. However, when the growth model is individual based, it is usually too complex to be differentiated with respect to its parameters. As a result, the analytical GHMB estimators cannot be used. In this study, we developed a bootstrap approach for the GHMB inferential framework in order to combine individual-based forest growth models with remotely sensed data. Through simulation studies, we showed that the bootstrap estimators were nearly unbiased when both submodels were linear. The estimator of the parameter estimates remained nearly unbiased when submodel $\mathcal{M}_{1}$ became complex, i.e. non-differentiable, and submodel $\mathcal{M}_{2}$ was nonlinear with heterogeneous variances and correlated error terms. The variance estimator showed some biases but these were relatively small. We further demonstrated through a real-world case study that the predictions of a complex individual-based model could be linked to a Landsat-8 near-infrared spectral band in the boreal forest zone of Quebec, Canada.

The Pulses of Soil CO2 Emission in Response to Rainfall Events in Central Siberia: Revisiting the Overall Frost-Free Season CO2 Flux

Boreal forests nowadays act as a sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to weather conditions and, specifically to ongoing climate warming. Extreme weather events such as heavy rainfalls or, conversely, heat waves during the growing season might perturb the ecosystem carbon balance and convert them to an additional CO2 source. Thus, there is an urgent need to revise ecosystem carbon fluxes in vast Siberian taiga ecosystems as influenced by extreme weather events. In this study, we focused on the soil CO2 pulses appearing after the rainfall events and quantification of their input to the seasonal cumulative CO2 efflux in the boreal forests in Central Siberia. Seasonal measurements of soil CO2 fluxes (both soil respiration and net soil exchange) were conducted during three consecutive frost-free seasons using the dynamic chamber method. Seasonal dynamics of net soil exchange fluxes demonstrated positive values, reflecting that soil respiration rates exceeded CO2 uptake in the forest floor vegetation layer. Moreover, the heavy rains caused a rapid pulse of soil emissions and, as a consequence, the release of additional amounts of CO2 from the soil into the atmosphere. A single rain event may cause a 5–11-fold increase of the NSE flux compared to the pre-rainfall values. The input of CO2 pulses to the seasonal cumulative efflux varied from near zero to 39% depending on precipitation patterns of a particular season. These findings emphasize the critical need for more frequent measurements of soil CO2 fluxes throughout the growing season which capture the CO2 pulses induced by rain events. This approach has inevitable importance for the accurate assessment of seasonal CO2 soil emissions and adequate predictions of response of boreal pine forests to climatic changes.

Assessing spatial patterns of burn severity for guiding post-fire salvage logging in boreal forests of Eastern Canada

Areas affected by forest fires are increasing worldwide, making salvage logging (i.e., harvesting fire-affected trees) an increasingly used practice to reduce the economic impacts of fire on forestry. However, salvage logging can have strong ecological impacts, notably on post-fire forest regeneration and biodiversity. Burn severity (i.e., the degree to which fires impact the vegetation and soil) is also a central element that interacts with pre-fire forest characteristics and salvages logging to control post-fire forest dynamics and biodiversity. In an ecosystem-based forest management context, spatial patterns of burn severity should thus be considered when planning salvage logging operations. This study presents a simple and innovative method to generate burn severity maps with Landsat and Sentinel-2 multispectral imageries to support salvage logging operations rapidly after a fire event. We assembled a unique dataset involving 330 plots from 10 burns (from 2010 to 2020) in which burn severity has been estimated on the field using the composite burn index (CBI) approach in eastern North America. CBI values were modelled as a univariate function of changes in spectral indices using the first cloud-free post-fire satellite images taken after the burns. Our results demonstrate that using free satellite images with straightforward methods can produce reliable and ecologically meaningful burn severity maps within the few weeks following a fire event. The method was then applied to a case study with salvage logging that illustrates how our burn severity maps could be a useful tool for guiding post-fire forestry operations in an ecosystem-based management context. We combined burn severity maps with pre-fire forest composition and age maps to assess immediate post-fire forest. We discuss how such an approach helps to guide salvage planning and maintain residual forests that are representative of the initial post-fire spatial variability in burn severity and pre-fire vegetation. We conclude that rapid mapping of burn severity after a forest fire event may offer many other applications for identifying and managing recently burned forests.

Process-evaluation of forest aerosol-cloud-climate feedback shows clear evidence from observations and large uncertainty in models

Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooling of the surface via impacts on cloud radiative properties. Motivated by the considerable spread in feedback strength in Earth System Models (ESMs), we here use two long-term observational datasets from boreal and tropical forests, together with satellite data, for a process-based evaluation of the BVOC-aerosol-cloud feedback in four ESMs. The model evaluation shows that the weakest modelled feedback estimates can likely be excluded, but highlights compensating errors making it difficult to draw conclusions of the strongest estimates. Overall, the method of evaluating along process chains shows promise in pin-pointing sources of uncertainty and constraining modelled aerosol feedbacks.

Spatial and Temporal Variation in Primary Forest Growth in the Northern Daxing’an Mountains Based on Tree-Ring and NDVI Data

We used tree-ring width data of Larix gmelinii and Pinus sylvestris var. mongolica from the northern region of the Daxing’an Mountains, China; normalized difference vegetation index (NDVI) data; and microtopographic information (elevation, slope direction, slope gradient, and topographic location index) to assess spatiotemporal dynamics in the growth of the boreal forest and topographic patterns of forest decline under the background of climate warming. Forest growth trends were determined based on tree growth decline indicators and NDVI time series trends, and topographic patterns of forest decline were analyzed using the C5.0 decision tree model. More climatic information was present in the radial growth of the trees at higher elevations, and P. sylvestris var. mongolica was influenced strongly by climatic factors of the previous year. Since 1759, tree radial growth trends in the study area have experienced two recessions during 1878–1893 and 1935–1943, which were characterized by persistent narrow whorls of tree rings of below-average growth. Changes in NDVI and tree-ring information were similar, and they together indicate a high risk of declining forest growth in the northern Daxing’an Mountains after 2010, especially at higher elevations. The NDVI time series showed that the high temperatures in 2003 negatively affected forest growth in the study area, which was confirmed by the tree-ring data. The decision tree terrain model results had an accuracy of 0.861, and elevation was the most important terrain factor affecting forest decline. The relative importance of elevation, topographic position index, aspect, and slope was 58.41%, 17.70%, 16.81%, and 7.08%, respectively. Classification rule-based decision tree models can be used to quantify the effects of terrain factors on tree growth. This research methodology can aid the management of regional forestry resources and the conservation of forest resources under the background of climate change, which increases the risk of forest decline.

Biochar as a potential tool to mitigate nutrient exports from managed boreal forest: A laboratory and field experiment

AbstractForest management in drained forested peatlands can negatively affect water quality due to the increase in exports of organic matter and nutrients. Therefore, new methods to alleviate this impact are needed. In laboratory conditions, biochar has been shown to be a strong sorbent of organic and inorganic nutrients due to its high surface area and ion‐exchange capacity. However, evidence of the adsorption capacity in field conditions is lacking. Here, we studied the water purification performance of two different biochar feedstocks (wood‐ and garden residue‐based) in a 10‐day laboratory experiment where we incubated biochar with runoff water collected from drainage ditches in clear‐cut peatland forests. We measured changes in pH and concentrations of inorganic phosphorus (PO4), total dissolved nitrogen (TDN), and dissolved organic carbon (DOC). The biochar with the best adsorbent capacity in the laboratory experiment was then tested in field conditions in a replicated catchment‐scale experiment, where both clear‐cutting and ditch cleaning were performed. We determined the nutrient concentration of water at the inlet and outlet of biochar filters placed in outflow ditches of four catchments. We found that under laboratory conditions wood‐based biochar efficiently adsorbed TDN and DOC, however, it released PO4. Furthermore, we found that the biochar filters reduced TDN and DOC concentration in field conditions. However, the percentage decrease in concentration was dependent on the initial concentrations of nutrients in the water and could be considered low. Moreover, we found that the biochar in the filters increased in TN content over the course of the experiment. This suggests that a wood‐based biochar filter has the potential to be a water protection tool for reducing the export of nutrients from catchments with high nutrient concentration. And that the biochar from the ditches could be applied back to the regenerating forest catchment as a potential soil amendment, closing the nutrient cycle.

Shifts in microbial community composition and metabolism correspond with rapid soil carbon accumulation in response to 20 years of simulated nitrogen deposition

Anthropogenic nitrogen (N) deposition and fertilization in boreal forests frequently reduces decomposition and soil respiration and enhances C storage in the topsoil. This enhancement of the C sink can be as strong as the aboveground biomass response to N additions and has implications for the global C cycle, but the mechanisms remain elusive. We hypothesized that this effect would be associated with a shift in the microbial community and its activity, and particularly by fungal taxa reported to be capable of lignin degradation and organic N acquisition. We sampled the organic layer below the intact litter of a Norway spruce (Picea abies (L.) Karst) forest in northern Sweden after 20 years of annual N additions at low (12.5 kg N ha−1 yr−1) and high (50 kg N ha−1 yr−1) rates. We measured microbial biomass using phospholipid fatty-acid analysis (PLFA) and ergosterol measurements and used ITS metagenomics to profile the fungal community of soil and fine-roots. We probed the metabolic activity of the soil community by measuring the activity of extracellular enzymes and evaluated its relationships with the most N responsive soil fungal species. Nitrogen addition decreased the abundance of fungal PLFA markers and changed the fungal community in humus and fine-roots. Specifically, the humus community changed in part due to a shift from Oidiodendron pilicola, Cenococcum geophilum, and Cortinarius caperatus to Tylospora fibrillosa and Russula griseascens. These microbial community changes were associated with decreased activity of Mn-peroxidase and peptidase, and an increase in the activity of C acquiring enzymes. Our results show that the rapid accumulation of C in the humus layer frequently observed in areas with high N deposition is consistent with a shift in microbial metabolism, where decomposition associated with organic N acquisition is downregulated when inorganic N forms are readily available.

Long-term aerosol particle depolarization ratio measurements with HALO Photonics Doppler lidar

Abstract. It has been demonstrated that HALO Photonics Doppler lidars (denoted HALO Doppler lidar hereafter) have the capability for retrieving the aerosol particle depolarization ratio at a wavelength of 1565 nm. For these lidars operating at such a long wavelength, the retrieval quality depends to a large degree on an accurate representation of the instrumental noise floor and the performance of the internal polarizer, whose stability has not yet been assessed for long-term operation. Here, we use 4 years of measurements at four sites in Finland to investigate the long-term performance of HALO Doppler lidars, focusing on aerosol particle depolarization ratio retrieval. The instrumental noise level, represented by noise-only signals in aerosol- and hydrometeor-free regions, shows stable performance for most instruments but clear differences between individual instruments. For all instruments, the polarizer bleed-through evaluated at liquid cloud base remains reasonably constant at approximately 1 % with a standard deviation of less than 1 %. We find these results to be sufficient for long-term aerosol particle depolarization ratio measurements and proceed to analyse the seasonal and diurnal cycles of the aerosol particle depolarization ratio in different environments in Finland, including in the Baltic Sea archipelago, a boreal forest and rural sub-arctic. To do so, we further develop the background correction method and construct an algorithm to distinguish aerosol particles from hydrometeors. The 4-year averaged aerosol particle depolarization ratio ranges from 0.07 in sub-arctic Sodankylä to 0.13 in the boreal forest in Hyytiälä. At all sites, the aerosol particle depolarization ratio is found to peak during spring and early summer, even exceeding 0.20 at the monthly-mean level, which we attribute to a substantial contribution from pollen. Overall, our observations support the long-term usage of HALO Doppler lidar depolarization ratio measurements, including detection of aerosols that may pose a safety risk for aviation.

Décalage temporel dans l’établissement des érables en forêt boréale révélé par une population marginale à la limite nordique de l’érable à sucre

ABSTRACT Given their position at the limit of a species’ bioclimatic tolerance envelope, range-edge populations are particularly sensitive to variations in environmental conditions. Understanding ecological history of such peripheral populations provides key insights about ecosystem responses and resilience to global change. Here, we rely on soil macrofossil charcoal analysis to infer the origin and dynamics of a marginal sugar maple stand located within the boreal forest, at the leading edge of the species range. Radiocarbon dating of sugar maple and red maple charcoal particles indicates a late origin of the sugar maple stand at c. 600 cal yr BP, compared to red maple, which was established in the early Neoglacial period c. 4000 years ago. The earlier presence of red maple may have facilitated a later establishment of sugar maple in the boreal environment, most likely by altering edaphic conditions. The relatively recent establishment of a disjunct stand of maple at its current leading edge suggests that models predicting a northward migration of temperate species to the boreal biome in response to contemporary climate change are empirically plausible.

Editorial: Achieving sustainable development goal 13: resilience and adaptive capacity of temperate and boreal forests under climate change

Editorial: Achieving sustainable development goal 13: resilience and adaptive capacity of temperate and boreal forests under climate change

Can the Impact of Gravel Roads on Organic Layer Thickness Explain the Distribution of Populus tremuloides along Road Networks in the Boreal Forest of Eastern Canada?

Roads are known to alter environmental conditions and the composition of road edge plant communities, particularly when exogenous materials are used as road surfacing. In this study, we evaluate the impact of gravel roads on the organic layer thickness (OLT) and aspen distribution in a boreal forest landscape of Eastern Canada. The OLT and aspen distribution were compared at different distances from the roads (0 m, 10 m, and >10 m) to determine whether a reduction in the OLT along the roads could explain the distribution of aspen along the road network, and in particular the role of the roads as habitat corridors. In addition, germination tests were carried out to determine whether mineral soil from the roads could promote aspen establishment, by comparing the germination rate of substrates consisting only of mineral soil or mosses, and substrates consisting of mosses covered with 0.5 cm or 2 cm of mineral soil. The presence of aspen in the study landscape is limited by thick organic deposits (≥50 cm). However, the thickness of these deposits is reduced to approximately 10 cm at the edges of gravel roads, in part by the transport of mineral soil from the roads. This reduction in the OLT facilitates the establishment of aspen and helps explain its distribution along the road network.

LC‐ICP‐MS analysis of inositol phosphate isomers in soil offers improved sensitivity and fine‐scale mapping of inositol phosphate distribution

Abstract Organic forms of phosphorus (P) prevail in soils and their quantification is vital to better understand global biogeochemical cycles. P speciation in soil is commonly assessed by 31P NMR spectroscopy of sodium hydroxide‐EDTA (NaOH‐EDTA) extracts. A liquid chromatography‐inductively coupled plasma‐mass spectrometry (LC‐ICP‐MS) method that employs NaOH‐EDTA is described. Comparison with 31P NMR shows that LC‐ICP‐MS is up to three orders of magnitude more sensitive. It allows measurement in samples as small as 1 mg. We reveal variation of inositol phosphate distribution in Swedish boreal forest soil and identify myo‐ and scyllo‐inositol hexakisphosphates and other isomers including scyllo‐inositol pentakisphosphate. Speciation of the major inositol phosphates was not altered by long‐term nitrogen fertilization.