Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The use of soil nutrient balances in deriving forest biomass harvesting guidelines specific to region, tree species and soil type in the Netherlands
    Vries, Wim de; Jong, Anjo de; Kros, Johannes ; Spijker, Joop - \ 2020
    Forest Ecology and Management 479 (2020). - ISSN 0378-1127
    Forest - Harvest residues - Harvesting guidelines - Netherlands - Nutrient availability - Nutrient balance - Timber harvesting

    The substitution of biomass for fossil fuels in energy consumption is a measure to decrease the emissions of greenhouse gases and thereby mitigate global warming. During recent years, this has led to an increasing interest to use tree harvest residues as feedstock for bioenergy. An important concern related to the removal of harvesting residues is, however, the potential adverse effects on soil fertility caused by increased nutrient removal, relative to conventional stem-only harvesting. In the Netherlands this is a major concern, since most forests are located on poor sandy soils. To develop forest harvesting guidelines, we applied a mass balance approach comparing nutrient inputs by deposition and weathering with nutrient outputs by harvesting and leaching for various timber harvesting scenarios, including both stem-only harvesting and additional removal of tree tops and branches. A distinction was made in seven major tree species, six soil types (three sandy soils, loam, clay and peat soils) and nine regions, with clear variations in atmospheric deposition of phosphorus (P), calcium (Ca), magnesium (Mg) and potassium (K). For each region-tree-soil combination we calculated the maximum amounts that can be harvested such that the output of the nutrients Ca, Mg, K and P is balanced with the inputs. Results showed that at current harvesting rates, a negative balance of Ca, Mg, K or P is hardly calculated for the richer loamy to clayey soil types, while depletion can occur for the poorer sandy soils, particularly of P and K. Results are used to derive forest biomass harvesting guidelines, taking the uncertainties in the mass balance approach into account. The role of mitigating management approaches is also discussed.

    Soil erosion along a transect in a forested catchment: Recent or ancient processes?
    Calitri, Francesca ; Sommer, Michael ; Meij, Marijn W. van der; Egli, Markus - \ 2020
    Catena 194 (2020). - ISSN 0341-8162
    239+240 Plutonium - Forest - Moraine landscape - Soil catena - Soil erosion

    Forested areas are assumed not to be influenced by erosion processes. However, forest soils of Northern Germany in a hummocky ground moraine landscape can sometimes exhibit a very shallow thickness on crest positions and buried soils on slope positions. The question consequently is: Are these on-going or ancient erosional and depositional processes? Plutonium isotopes act as soil erosion/deposition tracers for recent (last few decades) processes. Here, we quantified the 239+240Pu inventories in a small, forested catchment (ancient forest “Melzower Forst”, deciduous trees), which is characterised by a hummocky terrain including a kettle hole. Soil development depths (depth to C horizon) and 239+240Pu inventories along a catena of sixteen different profiles were determined and correlated to relief parameters. Moreover, we compared different modelling approaches to derive erosion rates from Pu data. We find a strong relationship between soil development depths, distance-to-sink and topography along the catena. Fully developed Retisols (thicknesses > 1 m) in the colluvium overlay old land surfaces as documented by fossil Ah horizons. However, we found no relationship of Pu-based erosion rates to any relief parameter. Instead, 239+240Pu inventories showed a very high local, spatial variability (36–70 Bq m−2). Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240Pu inventories, giving rise to a patchy input pattern. Different models resulted in quite similar erosion and deposition rates (max: −5 t ha−1 yr−1 to +7.3 t ha−1 yr−1). Although some rates are rather high, the magnitude of soil erosion and deposition - in terms of soil thickness change - is negligible during the last 55 years. The partially high values are an effect of the patchy Pu deposition on the forest floor. This forest has been protected for at least 240 years. Therefore rather natural events and anthropogenic activities during medieval times or even earlier must have caused the observed soil pattern, which documents strong erosion and deposition processes.

    Effects of nitrogen addition on soil methane uptake in global forest biomes
    Xia, Nan ; Du, Enzai ; Wu, Xinhui ; Tang, Yang ; Wang, Yang ; Vries, Wim de - \ 2020
    Environmental Pollution 264 (2020). - ISSN 0269-7491
    Forest - Nitrogen addition - Nitrogen deposition - Soil methane uptake

    Nitrogen (N) deposition has been conventionally thought to decrease forest soil methane (CH4) uptake, while the biome specific and dose dependent effect is poorly understood. Based on a meta-analysis of 63 N addition trials from 7 boreal forests, 8 temperate forests, 13 subtropical and 4 tropical forests, we evaluated the effects of N addition on soil CH4 uptake fluxes across global forest biomes. When combining all N addition levels, soil CH4 uptake was insignificantly decreased by 7% in boreal forests, while N addition significantly decreased soil CH4 uptake by 39% in temperate forests and by 21% in subtropical and tropical forests, respectively. Meta-regression analyses, however, indicated a shift from a positive to a negative effect on soil CH4 uptake with increasing N additions both in boreal forests (threshold = 48 kg N ha−1 yr−1) and temperate forests (threshold = 27 kg N ha−1 yr−1), while no such shift was found in subtropical and tropical forests. Considering that current N deposition to most boreal and temperate forests is below the abovementioned thresholds, N deposition likely exerts a positive to neutral effect on soil CH4 uptake in both forest biomes. Our results provide new insights on the biome specific and dose dependent effect of N addition on soil CH4 sink in global forests and suggest that the current understanding that N deposition decreases forest soil CH4 uptake is flawed by high levels of experimental N addition.

    Assessment of workflow feature selection on forest LAI prediction with sentinel-2A MSI, landsat 7 ETM+ and Landsat 8 OLI
    Brede, Benjamin ; Verrelst, Jochem ; Gastellu-Etchegorry, Jean Philippe ; Clevers, Jan G.P.W. ; Goudzwaard, Leo ; Ouden, Jan den; Verbesselt, Jan ; Herold, Martin - \ 2020
    Remote Sensing 12 (2020)6. - ISSN 2072-4292
    Discrete anisotropic radiative transfer (DART) model - Forest - Leaf area index (LAI) - Machine learning - Sentinel-2 - Vegetation radiative transfer model

    The European Space Agency (ESA)'s Sentinel-2A (S2A) mission is providing time series that allow the characterisation of dynamic vegetation, especially when combined with the National Aeronautics and Space Administration (NASA)/United States Geological Survey (USGS) Landsat 7 (L7) and Landsat 8 (L8) missions. Hybrid retrieval workflows combining non-parametric Machine Learning Regression Algorithms (MLRAs) and vegetation Radiative Transfer Models (RTMs) were proposed as fast and accurate methods to infer biophysical parameters such as Leaf Area Index (LAI) from these data streams. However, the exact design of optimal retrieval workflows is rarely discussed. In this study, the impact of five retrieval workflow features on LAI prediction performance of MultiSpectral Instrument (MSI), Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI) observations was analysed over a Dutch beech forest site for a one-year period. The retrieval workflow features were the (1) addition of prior knowledge of leaf chemistry (two alternatives), (2) the choice of RTM (two alternatives), (3) the addition of Gaussian noise to RTM produced training data (four and five alternatives), (4) possibility of using Sun Zenith Angle (SZA) as an additional MLRA training feature (two alternatives), and (5) the choice of MLRA (six alternatives). The featureswere varied in a full grid resulting in 960 inversionmodels in order to find the overall impact on performance as well as possible interactions among the features. A combination of a Terrestrial Laser Scanning (TLS) time series with litter-trap derived LAI served as independent validation. The addition of absolute noise had the most significant impact on prediction performance. It improved the median prediction RootMean Square Error (RMSE) by 1.08m2m-2 when 5% noise was added compared to inversions with 0% absolute noise. The choice of the MLRA was second most important in terms of median prediction performance, which differed by 0.52m2m-2 between the best and worst model. The best inversion model achieved an RMSE of 0.91m2m-2 and explained 84.9% of the variance of the reference time series. The results underline the need to explicitly describe the used noise model in future studies. Similar studies should be conducted in other study areas, both forest and crop systems, in order to test the noise model as an integral part of hybrid retrieval workflows.

    Data from: Patterns of nitrogen-fixing tree abundance in forests across Asia and America
    Menge, Duncan N.L. ; Chisholm, Ryan A. ; Davies, Stuart J. ; Abu Salim, Kamariah ; Allen, David ; Alvarez, Mauricio ; Bourg, Norm ; Brockelman, Warren Y. ; Bunyavejchewin, Sarayudh ; Butt, Nathalie ; Ouden, Jan den; Jansen, Patrick - \ 2019
    Determinants of plant community diversity and structure - Forest - Smithsonian ForestGEO - legume - symbiosis - nutrient limitation - nitrogen fixation
    Symbiotic nitrogen (N)‐fixing trees can provide large quantities of new N to ecosystems, but only if they are sufficiently abundant. The overall abundance and latitudinal abundance distributions of N‐fixing trees are well characterised in the Americas, but less well outside the Americas. Here, we characterised the abundance of N‐fixing trees in a network of forest plots spanning five continents, ~5,000 tree species and ~4 million trees. The majority of the plots (86%) were in America or Asia. In addition, we examined whether the observed pattern of abundance of N‐fixing trees was correlated with mean annual temperature and precipitation. Outside the tropics, N‐fixing trees were consistently rare in the forest plots we examined. Within the tropics, N‐fixing trees were abundant in American but not Asian forest plots (~7% versus ~1% of basal area and stems). This disparity was not explained by mean annual temperature or precipitation. Our finding of low N‐fixing tree abundance in the Asian tropics casts some doubt on recent high estimates of N fixation rates in this region, which do not account for disparities in N‐fixing tree abundance between the Asian and American tropics. Synthesis. Inputs of nitrogen to forests depend on symbiotic nitrogen fixation, which is constrained by the abundance of N‐fixing trees. By analysing a large dataset of ~4 million trees, we found that N‐fixing trees were consistently rare in the Asian tropics as well as across higher latitudes in Asia, America and Europe. The rarity of N‐fixing trees in the Asian tropics compared with the American tropics might stem from lower intrinsic N limitation in Asian tropical forests, although direct support for any mechanism is lacking. The paucity of N‐fixing trees throughout Asian forests suggests that N inputs to the Asian tropics might be lower than previously thought.
    Effects of long-term deforestation and remnant forests on rainfall and temperature in the Central Rift Valley of Ethiopia
    Muluneh, Alemayehu ; Loon, Emiel van; Bewket, Woldeamlak ; Keesstra, Saskia ; Stroosnijder, Leo ; Burka, Ashenafi - \ 2017
    Forest Ecosystems 4 (2017)1. - ISSN 2095-6355
    Deforestation - Elevation - Forest - Rainfall - Slope - Temperature

    Background: Some evidence suggests that forests attract rain and that deforestation contributes to changes in rainfall and temperature. The evidence, however, is scant, particularly on smaller spatial scales. The specific objectives of the study were: (i) to evaluate long-term trends in rainfall (1970–2009) and temperature (1981–2009) and their relationships with change in forest cover, and (ii) to assess the influence of remnant forests and topographical factors on the spatial variability of annual rainfall. Methods: This study investigated the forest-rainfall relationships in the Central Rift Valley of Ethiopia. The study used 16 long-term (1970–2009) and 15 short-term (2012–2013) rainfall and six long term (1981–2009) temperature datasets. Forest and woodland cover decline over the past 40 years (1970–2009) and the measured distances between the remnant forests and rainfall stations were also used. The long-term trends in rainfall (1970–2009) and temperature (1981–2009) were determined using Mann-Kendall (MK) and Regional Kendall (RK) tests and their relationships with long-term deforestation were evaluated using simple linear regression. Influence of remnant forests and topographical variables on the spatial variability of rainfall were determined by stepwise multiple regression method. A continuous forest and woodland cover decline was estimated using exponential interpolation. Results: The forest and woodland cover declined from 44% in 1973 to less than 15% in 2009 in the Central Rift Valley. Annual rainfall on the valley floor showed an increase by 37.9 mm/decade while annual rainfall on the escarpments/highlands decreased by 29.8 mm/decade. The remnant forests had a significant effect (P-value <0.05, R2 = 0.40) on the spatial variability of the number of rainy days observed over two years (2012–2013), but had little effect on the variability of rainfall distribution. For the total annual rainfall, slope was the best predictor which explained 29% of the rainfall variability in the Central Rift Valley. For the annual number of rainy days, both slope and elevation explained most of the variability (60%) of annual number of rainy days. Conclusion: This study did not find a significant correlation between long-term rainfall trend and forest and woodland cover decline. The rift valley floor warmed significantly due to long-term deforestation in the Central Rift Valley. Topographic factors play a significant role than forest cover in explaining the spatial variability of annual rainfall in the long-term and short term time scale in the Central Rift Valley. But, the short-term rainfall data indicated that the remnant forest had a significant effect on the spatial variability of the number of rainy days.

    Modelling long-term impacts of changes in climate, nitrogen deposition and ozone exposure on carbon sequestration of European forest ecosystems
    Vries, Wim de; Posch, Maximilian ; Simpson, David ; Reinds, Gert Jan - \ 2017
    Science of the Total Environment 605-606 (2017). - ISSN 0048-9697 - p. 1097 - 1116.
    Carbon sequestration - Climate change - CO - Forest - Nitrogen deposition - Ozone
    We modelled the effects of past and expected future changes in climate (temperature, precipitation), CO2 concentration, nitrogen deposition (N) and ozone (O3) exposure (phytotoxic ozone dose, POD) on carbon (C) sequestration by European forest ecosystems for the period 1900–2050. Tree C sequestration was assessed by using empirical response functions, while soil C sequestration was simulated with the process-based model VSD, combined with the RothC model. We evaluated two empirical growth responses to N deposition (linear and non-linear) and two O3 exposure relationships (linear function with total biomass or net annual increment). We further investigated an ‘interactive model’ with interactions between drivers and a ‘multiplicative model’, in which the combined effect is the product of individual drivers. A single deposition and climate scenario was used for the period 1900–2050. Contrary to expectations, growth observations at European level for the period 1950–2010 compared better with predictions by the multiplicative model than with the interactive model. This coincides with the fact that carbon responses in kg C ha− 1 yr− 1 per unit change in drivers, i.e. per °C, ppm CO2, kg N ha− 1 yr− 1 and mmol m− 2 yr− 1 POD, are more in line with literature data when using the multiplicative model. Compared to 1900, the estimated European average total C sequestration in both forests and forest soils between 1950 and 2000 increased by 21% in the interactive model and by 41% in the multiplicative model, but observed changes were even higher. This growth increase is expected to decline between 2000 and 2050. The simulated changes between 1950 and 2000 were mainly due to the increase in both N deposition and CO2, while the predicted increases between 2000 and 2050 were mainly caused by the increase in CO2 and temperature, and to lesser extent a decrease in POD, counteracted by reduced N deposition.
    Trees, forests and water : Cool insights for a hot world
    Ellison, David ; Morris, Cindy E. ; Locatelli, Bruno ; Sheil, Douglas ; Cohen, Jane ; Murdiyarso, Daniel ; Gutierrez, Victoria ; Noordwijk, Meine van; Creed, Irena F. ; Pokorny, Jan ; Gaveau, David ; Spracklen, Dominick V. ; Tobella, Aida Bargués ; Ilstedt, Ulrik ; Teuling, Adriaan J. ; Gebrehiwot, Solomon Gebreyohannis ; Sands, David C. ; Muys, Bart ; Verbist, Bruno ; Springgay, Elaine ; Sugandi, Yulia ; Sullivan, Caroline A. - \ 2017
    Global environmental change : human and policy dimensions 43 (2017). - ISSN 0959-3780 - p. 51 - 61.
    Adaptation - Carbon - Climate - Energy - Forest - Mitigation - Reforestation - Sustainability - Water
    Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity's ability to protect our planet's climate and life-sustaining functions. The substantial body of research we review reveals that forest, water and energy interactions provide the foundations for carbon storage, for cooling terrestrial surfaces and for distributing water resources. Forests and trees must be recognized as prime regulators within the water, energy and carbon cycles. If these functions are ignored, planners will be unable to assess, adapt to or mitigate the impacts of changing land cover and climate. Our call to action targets a reversal of paradigms, from a carbon-centric model to one that treats the hydrologic and climate-cooling effects of trees and forests as the first order of priority. For reasons of sustainability, carbon storage must remain a secondary, though valuable, by-product. The effects of tree cover on climate at local, regional and continental scales offer benefits that demand wider recognition. The forest- and tree-centered research insights we review and analyze provide a knowledge-base for improving plans, policies and actions. Our understanding of how trees and forests influence water, energy and carbon cycles has important implications, both for the structure of planning, management and governance institutions, as well as for how trees and forests might be used to improve sustainability, adaptation and mitigation efforts.
    The contribution of atmospheric deposition and forest harvesting to forest soil acidification in China since 1980
    Zhu, Qichao ; Vries, Wim De; Liu, Xuejun ; Zeng, Mufan ; Hao, Tianxiang ; Du, Enzai ; Zhang, Fusuo ; Shen, Jianbo - \ 2016
    Atmospheric Environment 146 (2016). - ISSN 1352-2310 - p. 215 - 222.
    Atmospheric deposition - Base cation - Element uptake - Forest - PH - Soil acidification

    Soils below croplands and grasslands have acidified significantly in China since the 1980s in terms of pH decline in response to acid inputs caused by intensified fertilizer application and/or acid deposition. However, it is unclear what the rate is of pH decline of forest soils in China in response to enhanced acid deposition and wood production over the same period. We therefore gathered soil pH data from the Second National Soil Inventory of China and publications from the China National Knowledge Infrastructure (CNKI) database in 1981-1985 and 2006-2010, respectively, to evaluate the long-term change of pH values in forest soils. We found that soil pH decreased on average by 0.36 units in the period 1981-1985 to 2006-2010., with most serious pH decline occurring in southwest China (0.63 pH units). The soil type with the strongest pH decline was the semi-Luvisol (0.44 pH units). The decrease in pH was significantly correlated with the acid input induced by atmospheric deposition and forest harvesting. On average, the contribution of atmospheric deposition to the total acid input was estimated at 84% whereas element uptake (due to forest wood growth and harvest) contributed 16% only. Atmospheric deposition is thus the major driver for the significant forest soil acidification across China.

    Water repellency under coniferous and deciduous forest - Experimental assessment and impact on overland flow
    Butzen, Verena ; Seeger, Manuel ; Marruedo, Amaia ; Jonge, Lianne de; Wengel, René ; Ries, Johannes B. ; Casper, Markus C. - \ 2015
    Catena 133 (2015). - ISSN 0341-8162 - p. 255 - 265.
    Forest - Overland flow - Soil water repellency - WDPT

    Current climate change makes it necessary to gain a deeper understanding of the runoff generation processes in Central European forests. A changing climate might affect soil water repellency (SWR) which can be seen as an import trigger for overland flow generation in forested areas. In this study the differences between coniferous and deciduous forest concerning SWR and overland flow generation were investigated in a small catchment in the Hunsrück low mountain range, Rhineland-Palatinate, Germany.To investigate the occurrence and persistence of SWR and its influence on overland flow generation, a combination of two experimental methods was applied: water drop penetration time (WDPT) test, and rainfall experiments. The field WDPT test results ranged from wettable (WDPT-1 rainfall intensity yielded runoff coefficients between 0% and 63%. The lowest measured infiltration rate of the rainfall experiments was 11.6mmh-1. The highest runoff coefficients were measured on water repellent (WDPT>300s) coniferous forest sites. The overland flow starts significantly earlier with water repellent soil conditions. The median runoff rate for the wettable forest soils is 2.7%, whereas the water repellent sites show a median runoff coefficient of 11.4%.The results suggest that the occurrence of SWR can lead to considerable overland flow generation under forest.

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