Het niemandsland van de science wars: een historische en filosofische reflectie over “postmodernisme” en de studie van wetenschap

In this article, I provide a historical and philosophical discussion of the so-called “science wars”. The term “science wars” refers to a series of debates which took place in the second half of the 1990s and which centered on the status of science and the nature of scientific knowledge. On the one hand, a group of authors reacted against what they perceived as a “postmodern” attack on science. This in turn led to several reactions from those who were labeled as “postmodernists”. Among these, some authors in turn claimed that it were the scientists and their epigones who were the real aggressors, using the authority of science to attack any form of critical thinking and even democracy itself. I first provide a short historical overview and analysis of the science wars. The aim of this overview is to show how critics of postmodernism ignored differences between different approaches in science studies and in this way constructed the idea of the existence of a homogeneous postmodern attack on science. This resulted in an intellectual trench war, in which more nuanced positions got overlooked, being trapped in the no man’s land between two extreme positions. After this historical overview, I explore this no man’s land. I discuss several scholars and approaches within science studies that had been grouped together by critics of postmodernism. I will focus on the differences between these approaches, thus providing a more nuanced picture of science studies. Finally, I argue for the relevance of revisiting the science wars. Blindly labelling (certain approaches in) science studies as “anti science” disables us from using important insights from these studies, insights which could be relevant in dealing with complex societal issues in which scientific knowledge plays a role such as climate change

Strong Foundations: Petrus van Musschenbroek’s experimental research on the strength of materials

In this article, I discuss Petrus van Musschenbroek's research on the strength of materials in relation to his methodological views. In the latter, van Musschenbroek emphasizes the importance of repeating and varying experiments. This is related to his views on the complexity of nature, which play a role in his views onmathematics, laws of nature, causes, and experimental method. In each case, the construction of an (experimental) history is presented as a first step in experimental philosophy, necessary to deal with the complexity of nature. The experimental research on the strength ofmaterials can likewise be seen as aimed at the construction of an (experimental) history. His experimental practice takes the form of a systematic variation of parameters and the performance of an extensive series of experiments on different kinds of substances. In his experimental reports, van Musschenbroek repeatedly points to the utility of his experimental results. This utilitarian attitude is typical for the experimental history literature as discussed by Klein. Van Musschenbroek himself also presents his work as an experimental history. However, unlike the examples discussed by Klein, van Musschenbroek's experimental history is characterized by a systematic experimental method. I argue that this method can be seen as an example of exploratory experimentation in Steinle's sense. Finally, I suggest that with its emphasis on the nature and properties of specific materials, it could be fruitful to read van Musschenbroek's experimental history in light of the emergence of engineering as a discipline in the eighteenth century

Understanding the temporal dimension of the red-edge spectral region for forest decline detection using high-resolution hyperspectral and Sentinel-2a imagery

The operational monitoring of forest decline requires the development of remote sensing methods that are sensitive to the spatiotemporal variations of pigment degradation and canopy defoliation. In this context, the red-edge spectral region (RESR) was proposed in the past due to its combined sensitivity to chlorophyll content and leaf area variation. In this study, the temporal dimension of the RESR was evaluated as a function of forest decline using a radiative transfer method with the PROSPECT and 3D FLIGHT models. These models were used to generate synthetic pine stands simulating decline and recovery processes over time and explore the temporal rate of change of the red-edge chlorophyll index (CI) as compared to the trajectories obtained for the structure-related Normalized Difference Vegetation Index (NDVI). The temporal trend method proposed here consisted of using synthetic spectra to calculate the theoretical boundaries of the subspace for healthy and declining pine trees in the temporal domain, defined by CItime=n/CItime=n+1 vs. NDVItime=n/NDVItime=n+1. Within these boundaries, trees undergoing decline and recovery processes showed different trajectories through this subspace. The method was then validated using three high-resolution airborne hyperspectral images acquired at 40 cm resolution and 260 spectral bands of 6.5 nm full-width half-maximum (FWHM) over a forest with widespread tree decline, along with field-based monitoring of chlorosis and defoliation (i.e., ‘decline’ status) in 663 trees between the years 2015 and 2016. The temporal rate of change of chlorophyll vs. structural indices, based on reflectance spectra extracted from the hyperspectral images, was different for trees undergoing decline, and aligned towards the decline baseline established using the radiative transfer models. By contrast, healthy trees over time aligned towards the theoretically obtained healthy baseline. The applicability of this temporal trend method to the red-edge bands of the MultiSpectral Imager (MSI) instrument on board Sentinel-2a for operational forest status monitoring was also explored by comparing the temporal rate of change of the Sentinel-2-derived CI over areas with declining and healthy trees. Results demonstrated that the Sentinel-2a red-edge region was sensitive to the temporal dimension of forest condition, as the relationships obtained for pixels in healthy condition deviated from those of pixels undergoing decline.JRC.D.1-Bio-econom

The feasibility of detecting trees affected by the Pine Wood Nematode using remote sensing

On request of DG SANTE , the Joint Research Centre has conducted between November 2014 and April 2015 a pilot study to establish the feasibility of remote sensing based detection of trees affected by Pine Wood Nematode (PWN) in the 2.2 Mha buffer zone established along the Portuguese and Spanish border. JRC collected multiple types of remote sensing data, from both aircraft and satellites, and a range of sensors and resolutions over a 7000 ha study site in Spain in the winter of 2014-2015. The images were evaluated for their ability to distinguish a) between pine trees that appeared to have a healthy canopy, and those showing decline, and b) between different levels of canopy decline, in terms of defoliation, decolouration and die-off. Detailed analysis of the imagery showed that when properly processed, remote sensing observations, particularly at high spatial and spectral resolution from aircraft, do permit the identification of pine trees showing canopy decline. The ability to detect individual tree crowns, and varying levels of canopy decline, varied with the image resolution, the type of sensor used to acquire the data, and the level of processing of the data. Based on the findings of this study the report spells out a set of technical recommendations for the operational monitoring of tree canopy health over large areas in the context of tree pest oubreaks.JRC.H.3-Forest Resources and Climat

Small world in the real world: Long distance dispersal governs epidemic dynamics in agricultural landscapes

Outbreaks of a plant disease in a landscape can be meaningfully modelled using networks with nodes representing individual crop-fields, and edges representing potential infection pathways between them. Their spatial structure, which resembles that of a regular lattice, makes such networks fairly robust against epidemics. Yet, it is well-known how the addition of a few shortcuts can turn robust regular lattices into vulnerable ‘small world’ networks. Although the relevance of this phenomenon has been shown theoretically for networks with nodes corresponding to individual host plants, its real-world implications at a larger scale (i.e. in networks with nodes representing crop fields or other plantations) remain elusive. Focusing on realistic spatial networks connecting olive orchards in Andalusia (Southern Spain), the world’s leading olive producer, we show how even very small probabilities of long distance dispersal of infectious vectors result in a small-world effect that dramatically exacerbates a hypothetical outbreak of a disease targeting olive trees (loosely modelled on known epidemiological information on the bacterium Xylella fastidiosa, an important emerging threat for European agriculture). More specifically, we found that the probability of long distance vector dispersal has a disproportionately larger effect on epidemic dynamics compared to pathogen’s intrinsic infectivity, increasing total infected area by up to one order of magnitude (in the absence of quarantine). Furthermore, even a very small probability of long distance dispersal increased the effort needed to halt a hypothetical outbreak through quarantine by about 50% in respect to scenarios modelling local/short distance pathogen’s dispersal only. This highlights how identifying (and disrupting) long distance dispersal processes may be more efficacious to contain a plant disease epidemic than surveillance and intervention concentrated on local scale transmission processes.Peer reviewe

High-Latitude Tree Growth and Satellite Vegetation Indices: Correlations and Trends in Russia and Canada (1982-2008)

Vegetation in northern high latitudes affects regional and global climate through energy partitioning and carbon storage. Spaceborne observations of vegetation, largely based on the normalized difference vegetation index (NDVI), suggest decreased productivity during recent decades in many regions of the Eurasian and North American boreal forests. To improve interpretation of NDVI trends over forest regions, we examined the relationship between NDVI from the advanced very high resolution radiometers and tree ring width measurements, a proxy of tree productivity. We collected tree core samples from spruce, pine, and larch at 22 sites in northeast Russia and northwest Canada. Annual growth rings were measured and used to generate site-level ring width index (RWI) chronologies. Correlation analysis was used to assess the association between RWI and summer NDVI from 1982 to 2008, while linear regression was used to examine trends in both measurements. The correlation between NDVI and RWI was highly variable across sites, though consistently positive (r = 0.43, SD = 0.19, n = 27). We observed significant temporal autocorrelation in both NDVI and RWI measurements at sites with evergreen conifers (spruce and pine), though weak autocorrelation at sites with deciduous conifers (larch). No sites exhibited a positive trend in both NDVI and RWI, although five sites showed negative trends in both measurements. While there are technological and physiological limitations to this approach, these findings demonstrate a positive association between NDVI and tree ring measurements, as well as the importance of considering lagged effects when modeling vegetation productivity using satellite data

Vulnerability of European forests to natural disturbances

European forests provide a set of fundamental services that contribute to climate change mitigation and human well-being. At the same time, forests are vulnerable systems because the long life-span of trees limits the possibility of rapid adaptation to drastic environmental changes. Climate-driven disturbances in forests, such as fires, windstorms and insect outbreaks, are expected to rise drastically under global warming. As a result, key forest services, such as carbon sequestration and supply of wood materials, could be seriously affected in the near future. Despite the relevance and urgency of the issue, little is known about the vulnerability of European forests to multiple climate-related hazards and the adaptation benefits of alternative forest management strategies. To fill this knowledge gap we investigated the susceptibility of European forests when exposed to a given natural disturbance under different forest management scenarios. For this purpose, we assessed forest vulnerability by integrating in a data-driven framework satellite observations, national forest inventories, land surface climatic data and records of disturbances over the 2000-2017 period. The integration of these data streams is meant to capture the key drivers of vulnerability and to quantify, for the first time, the vulnerability of European forests to fires, windstorms and insect outbreaks in a systematic and spatially explicit manner. We point out that, the term vulnerability is used in this study to express to what degree a forest ecosystem is affected when exposed to a given disturbance. In order to derive risk estimates, vulnerability estimates should be integrated with hazard and exposure components, according to typical impact assessment frameworks. Results of this analyses show that in average at Europe level forest vulnerability to windstorms appears the disturbance with larger biomass loss both in relative and absolute terms (~38%, ~17 t ha-1) compared to fires (~24%, ~12.5 t ha-1) and insect outbreaks (~21%, ~9 t ha-1). Substantial spatial variations in vulnerability emerge and depict generally higher values in norther and Mediterranean regions. Overall, forest structural properties play a larger control on the vulnerability of European forests to natural disturbances compared to climate and landscape features. However, increases in temperature and changes in precipitation patterns occurred over the last two decades, have contributed substantially to make European forests more vulnerable to natural disturbances. We found that these changes in climate led to a limited increase in vulnerability at Europe for fires and windstorms and to a strong increase for insect outbreaks. However, contrasting regional trends emerging over Europe mask relevant temporal changes in vulnerability occurring at local scale. When analyses of single disturbances are combined together, results show that large part of the European forests are substantially vulnerable to at least one natural disturbance and that many of the areas more vulnerable have been subject to an amplification of vulnerability over the observational period due to changes in climate. Reducing tree age and tree density appear effective forest management strategies to reduce the vulnerability of European forests to climate-driven disturbances. The magnitude of the potential benefits appears strongly dependent on local environmental conditions. Previous assessments of future climate risks to European forests, based on catalogues of disturbances collected at country level, have showed that damage from fires, windstorms and insect outbreaks is likely to increase further in coming decades. Such intensification could offset the impact of land-based strategies aiming to increase the forest carbon sink. However, the country scale approach used in such studies do not allow to explore in detail the underlying physical processes and to elaborate adaptation strategies at appropriate local scales. It is therefore fundamental to elaborate new modelling approaches that address in explicit manner the high spatial and temporal variability of forest disturbances. In this respect, machine learning approaches and the increasing availability of multi-platform satellite observations of land surface in combination with high regional climate model simulations, represent valuable opportunities to appraise the impact of forest disturbances at a spatial and temporal resolution relevant for forest management strategies. This explorative study represents a first step towards such integrated framework.JRC.D.1-Bio-econom