Arne Verstraeten

• PhD; ir.
• Senior Researcher at Research Institute for Nature and Forest (INBO)

Throughout Europe and the USA, forest ecosystem functioning has been impacted by long-term excessive deposition of acidifying compounds. In this study, we report on trends in stand deposition and soil solution fluxes of inorganic nitrogen (N) and sulphur (S) compounds over a 17-year period (1994-2010) in five ICP Forests monitoring plots in Flander...

Dissolved organic carbon (DOC) in the soil solution of forests originates from a number of biologically and/or biochemically mediated processes, including litter decomposition and leaching, soil organic matter mineralization, root exudation, mucilage and microbial activity. A variable amount of DOC reaches the forest floor through deposition, but l...

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 nutrien...

Atmospheric deposition to forests has been monitored within the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) with sampling and analyses of bulk precipitation and throughfall at several hundred forested plots for more than 15 years. The current deposition of inorganic nitrogen (ni...

Nitrogen (N) depositions in Europe are decreasing, but this could not explain faster than expected improvement of N saturation indicators in temperate forests. Alongside there were local signs of initial recovery from acidification during the past three decades and enhanced leaching of dissolved organic carbon and nitrogen (DOC, DON). These two glo...

Tree-microbe interactions are essential for forest ecosystem functioning. Most plant–microbe research has focused on the rhizosphere, while composition of microbial communities in the phyllosphere remains underexplored. Here, we use 16S rRNA gene sequencing to explore differences between beech and Scots pine phyllospheric microbiomes at the Europea...

Climate change effects on tree reproduction are poorly understood, even though the resilience of populations relies on sufficient regeneration to balance increasing rates of mortality. Forest‐forming tree species often mast, i.e. reproduce through synchronised year‐to‐year variation in seed production, which improves pollination and reduces seed pr...

Human activities have greatly increased the reactive nitrogen in the biosphere, thus profoundly altering global nitrogen cycling. The large increase in nitrogen deposition over the past few decades has led to eutrophication in natural ecosystems, with negative effects on forest health and biodiversity. Recent studies, however, have reported oligotr...

Air Pollution Effects on Forests (ICP Forests) spanning over five European biogeographic regions from 2005 to 2018. Average values for VFS were calculated accounting for the number of species present and their observed frequency. Spatial and temporal variation of ozone concentrations, VFS, and their relationships across Europe were then investigate...

The effects of tree pollen on precipitation chemistry are not fully understood and this can lead to misinterpretations of element deposition in European forests. We investigated the relationship between forest throughfall (TF) element fluxes and the Seasonal Pollen Integral (SPIn) using linear mixed-effects modelling (LME). TF was measured in 1990–...

Atmospheric deposition of dissolved organic carbon (DOC) to terrestrial ecosystems is a small, but rarely studied component of the global carbon (C) cycle. Emissions of volatile organic compounds (VOC) and organic particulates are the sources of atmospheric C and deposition represents a major pathway for the removal of organic C from the atmosphere...

Monitoring volumetric soil water content (θv) is the key for assessing water availability and nutrient fluxes. This study evaluated the empirical accuracy of θv measurements using standard and in situ calibrated frequency domain reflectometers (FDR) with gravimetric water content and bulk density measurements of 1512 samples gathered from 15 profil...

This study aimed to simulate oak and beech forest growth under various scenarios of climate change and to evaluate how the forest response depends on site properties and particularly on stand characteristics using the individual process-based model HETEROFOR. First, this model was evaluated on a wide range of site conditions. We used data from 36 l...

The effects of pollen on dissolved inorganic nitrogen (DIN) compounds in throughfall water are not completely understood. We conducted a 7-day leaching experiment with pollen from silver birch (including a sterilized control), European beech, sessile oak, Scots pine, Corsican black pine and Norway spruce using an immersion medium containing nitrate...

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity, and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its...

Resource allocation to different plant tissues is likely to be affected by high investment into fruit production during mast years. However, there is a large knowledge gap concerning species-specific differences in resource dynamics. We investigated the influence of mast years on stem growth, leaf production, and leaf carbon (C), nitrogen (N), and...

Criterion 2 considers and quantifies the exposure, risk, and impact on forest health posed by biotic and abiotic stressors. Environmental conditions, such as air and soil quality, influence the health and vitality of forest ecosystem and, subsequently, the provision of forest products and services. Appropriate management practices can improve the c...

Understanding the drivers of net ecosystem exchange of carbon (NEE) between forests and the atmosphere is crucial for the prediction of future global carbon dynamics. We therefore analyzed the long-term (1999–2014) ecosystem carbon fluxes of a mixed coniferous/deciduous forest (Brasschaat forest) in the Campine ecoregion of Belgium. The carbon upta...

Changing environmental conditions may substantially interact with site quality and forest stand characteristics, and impact forest growth and carbon sequestration. Understanding the impact of the various drivers of forest growth is therefore critical to predict how forest ecosystems can respond to climate change. We conducted a continental-scale an...

Mast seeding, the synchronised occurrence of large amounts of fruits and seeds at irregular intervals, is a reproductive strategy in many wind-pollinated species. Although a series of studies have investigated mast year (MY) patterns in European forest tree species at the regional scale, there are few recent evaluations at a European scale on the i...

Average nitrogen (N) deposition across Europe has declined since the 1990s. This resulted in decreased N inputs to forest ecosystems especially in Central and Western Europe where deposition levels are highest. While the impact of atmospheric N deposition on forests has been receiving much attention for decades, ecosystem responses to the decline i...

In the HTML version of this Article, author 'Filipa Cox' had no affiliation in the author list, although she was correctly associated with affiliation 3 (Earth & Environmental Sciences, University of Manchester, Manchester, UK) in the PDF. In addition, the blue circles for 'oak' were missing from Extended Data Fig. 1. These errors have been correct...

A 10-year long dataset of half-hourly ozone (O3) fluxes was used to study the variability in deposition velocity (υd) over a mixed temperate suburban forest. Average (median) υd amounted to 0.70 (0.46) cm s⁻¹, with day- and night-time average (median) of 0.98 (0.73) cm s⁻¹ and 0.46 (0.30) cm s⁻¹, respectively. It was found that the precipitation fo...

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litt...

Explaining the large-scale diversity of soil organisms that drive biogeochemical processes-and their responses to environmental change-is critical. However, identifying consistent drivers of belowground diversity and abundance for some soil organisms at large spatial scales remains problematic. Here we investigate a major guild, the ectomycorrhizal...

ICP Forests Briefs aim to provide clear and concise information on the ICP Forests monitoring programme and its latest scientific findings. These short updates are primarily directed at policymakers and the interested public offering them scientific knowledge for an informed debate on key forest-related environmental topics. Key messages of ICP Fo...

Litterfall is a major, yet poorly studied, process within forest ecosystems globally. It is important for carbon dynamics, edaphic communities, and maintaining site fertility. Reliable information on the carbon and nutrient input from litterfall, provided by litter traps, is relevant to a wide audience including policy makers and soil scientists. W...

Sulphur (S) is an essential plant nutrient. In the form of sulphate (SO42-) it is the principal anion in soil solution and a driver of base cation leaching from soils. Due to the reduction in S emissions, atmospheric sulphur dioxide (SO2) concentrations and S deposition in Europe decreased significantly in recent decades. However, few studies have...

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study we assessed the r...

Through litter decomposition enormous amount of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litte...

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to under-stand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litt...

Elevated depositions of non-marine sulphate (SO42-) and inorganic nitrogen (N), as a consequence of air pollution, resulted in a progressive acidification and eutrophication of Flemish forests. Since the 1980s emission abatement reduced the acidifying and eutrophying emissions and depositions in Flanders. This thesis aimed to evaluate the impact of...

Effects of N deposition to forest ecosystems N as limiting nutrient Shift in nutrient limitation / nutrient imbalances Changes in composition of ground vegetation and mycorrhiza Changes in soil processes N-Leaching

Motivatie In Vlaanderen zijn oude bomen en oude bossen een zeldzaam verschijnsel, en de kennis van hun historiek en ecologie is nog steeds beperkt. Wél is geweten dat oude en aftakelende bomen een heel hoge ecologische waarde hebben, die vaak nog hoger is dan die van zwaar dood hout. Vandaar dat hieraan steeds meer aandacht wordt besteed : ook in d...

Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas incr...

Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas incr...

We evaluated trends (2005–2013) and patterns of dissolved organic nitrogen (DON) and its ratio with dissolved organic carbon (DOC), DOC:DON in atmospheric deposition and soil solution of five Level II plots of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) in Flanders, Norther...

LTER-Belgium stands for “Long-Term Ecosystem Research Network in Belgium”. The kick-off of the LTER-Belgium network was given at the official recognition by the International Long-term Ecological Research (ILTER) network (annual meeting December 2014 in Ancud, Chiloe Island, Chile). At the beginning of 2016, LTER-Belgium comprises 27 sites and 5 pl...

Global environmental changes such as climate change, overexploitation and human population growth increase the interest in woody biomass from forests as a resource for green energy, chemistry and materials. Whole Tree Harvesting (WTH) can provide additional woody biomass, mainly for bioenergy, by harvesting parts of the crown not harvested under co...

Key messageExceedance of critical limits in soil solution samples was more frequent in intensively monitored forest plots across Europe with critical loads for acidity and eutrophication exceeded compared to other plots from the same network. Elevated inorganic nitrogen concentrations in soil solution tended to be related to less favourable nutriti...

Ectomycorrhizal fungi are major ecological players in temperate forests but they are rarely used in measures of forest condition because large-scale, high-resolution, standardized and replicated belowground data is scarce. We carried out an analysis of ectomycorrhizas at 22 intensively-monitored long-term oak plots, across nine European countries,...

Soil is the largest terrestrial carbon reserve; about 20% of all soil C is stored in forest soils. In a scenario of climatic change, the role of stable soil C pool for mitigation of greenhouse gases has increased the need for more knowledge on the mechanisms and factors that govern organic C sequestration, stability and dynamics in forest soil. Cli...

Accurate quantification of total nitrogen and acidifying deposition is a major source of uncertainty in determining the exceedance of critical loads in forest ecosystems. Monitoring of atmospheric deposition is frequently based on throughfall measurements in combination with the canopy budget model to calculate ion-exchange fluxes between the fores...

http://www.icp-forests.org/pdf/TR2012.pdf

The main goal of this study was to detect trends in deposition at ICP Forests Level II sites (with ICP Forests and pre-ICP Forests data) and to investigate possible causes. The specific objectives were to:  determine the bulk and throughfall deposition of sulphate and inorganic nitrogen (nitrate and ammonium) and its trends  investigate the influ...

Carbon taken up by the forest canopy is allocated to tree organs for biomass production and respiration. Because tree organs have different life span and decomposition rate, the tree C allocation determines the residence time of C in the ecosystem and its C cycling rate. The study of the carbon-use efficiency, or ratio between net primary productio...

Question: Does clear-felling influence forest herb colonization into post-agricultural forest? Location: A stand of poplar cultivars with a dense understorey of Acer pseudoplatanus in Muizen forest (northern Belgium), planted in 1952 on farmland adjacent to ancient forest and clear-felled in 1997. Methods: Shade-tolerant forest herbs were surveyed...

The impact of forest age (indicating the number of years of continuous forest cover), historical forest management and soil conditions on the forest plant species richness and composition were studied in 168 forest fragments in the Moervaart valley. The Moervaart valley is a large alluvial plain in the north of Flanders (Belgium) which originated f...

Excursion itinirary and extensive description DAY 1 (Saturday) Arrival in Bratislava, transfer to Zvolen DAY 2 (Sunday) Kováčovské kopce (hills) – South - national nature preservation A protected area established on 364 ha in 1966 in order to protect forest and forest-steppe ecosystems on the south slopes of the Burda Masiff. Occurence of numer...