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The rapid and accurate detection of forest disturbances in temperate forests has become increasingly crucial as policy demands and climate pressure on these forests rise. The cloud-penetrating Sentinel-1 radar constellation provides frequent and high-resolution observations with global coverage, but few studies have assessed its potential for mapping disturbances in temperate forests. This study investigated the sensitivity of temporally dense C-band backscatter data from Sentinel-1 to varying management-related disturbance intensities in temperate forests, and the influence of confounding factors such as radar backscatter signal seasonality, shadow, and layover on the radar backscatter signal at a pixel level. A unique network of 14 experimental sites in the Netherlands was used in which trees were removed to simulate different levels of management-related forest disturbances across a range of representative temperate forest species. Results from six years (2016–2022) of Sentinel-1 observations indicated that backscatter seasonality is dependent on species phenology and degree of canopy cover. The backscatter change magnitude was sensitive to medium- and high-severity disturbances, with radar layover having a stronger impact on the backscatter disturbance signal than radar shadow. Combining ascending and descending orbits and complementing polarizations compared to a single orbit or polarization was found to result in a 34% mean increase in disturbance detection sensitivity across all disturbance severities. This study underlines the importance of linking high-quality experimental ground-based data to dense satellite time series to improve future forest disturbance mapping. It suggests a key role for C-band backscatter time series in the rapid and accurate large-area monitoring of temperate forests and, in particular, the disturbances imposed by logging practices or tree mortality driven by climate change factors.

High demands on forest for carbon storage and provision of timber and biofuel require precise and reliable estimates of the biomass, carbon and nutrient stocks in different tree compartments. Whether the fraction of biomass distributed in aboveground tree compartments and the carbon and nutrient concentrations varies systematically across trees in different canopy positions remains unclear despite its importance for understanding forest ecology. Here, we compared the distribution of biomass, carbon and nutrients from underlying carbon and nutrient concentrations between different aboveground tree compartments for 15 mature trees of European beech (Fagus sylvatica), Douglas fir (Pseudotsuga menziesii) and Scots pine (Pinus sylvestris) with dominant, intermediate and suppressed canopy position. We show that carbon concentrations were relatively constant across tree compartments while nutrient concentrations increased from stem, bark, branches towards needles. Canopy position had only minor effects on carbon and nutrient concentrations and on the distribution of biomass, carbon and nutrients between aboveground tree components. Nutrient concentrations and stochiometric results confirm that the forests were affected by high N deposition and low availability of P and base cations. Our results imply that predictions from allometric scaling theory better apply to aboveground tree components than from functional equilibrium theory. Models aiming for estimating tree and forest biomass and carbon and nutrient stocks can apply equal biomass, carbon and nutrient stocks for trees independent of canopy position as a valid assumption but testing this assumption for a broader range of species and site conditions remains recommended.

The sustainability of tree harvest is questioned since harvest results in increased nutrient losses which may reduce nutrient stocks in forest soils, particularly in forests on acidified and poor soils with low base saturation. We used a new forest experiment to quantify nutrient stocks and nutrient uptake rates in mature forest stands, and to assess the forest nutrient balance in relation to different forest management scenarios: clearcutting, shelterwood and thinning; and whole-tree harvest (WTH), stem-only harvest (SOH) and wood only harvest (WOH, with on-site bark stripping). Forests were dominated by trees of Fagus sylvatica, Pseudotsuga Menziesii or Pinus sylvestris, all situated on poor, acidified soils. We measured forest biomass and nutrient stocks based on destructive sampling of fifteen mature trees per species and by using new, calibrated allometric relationships. Aboveground stocks of N, P, S, K, Ca, Mg, Mn, Cu, Fe and Zn were calculated for foliage, branches, stem bark and stem wood. Annual forest growth and nutrient uptake were determined using tree ring measures and allometric relationships. Organic layer nutrient stocks and available nutrients in the mineral soil were determined following intensive soil sampling. Stands of beech, Douglas fir and Scots pine differed in aboveground biomass and nutrient stocks, with highest biomass stocks in Douglas fir. However, beech stands had the highest aboveground nutrient stocks, nutrient uptake rates and nutrient losses following harvest, followed by Scots pine. Organic layer nutrient stocks generally exceeded aboveground nutrient stocks, except for the base cations and Mn. Compared to SOH, WTH increased nutrient export between 66% (Douglas fir) up to 100% (Scots pine), while WOH decreased the nutrient export between 23% (beech) up to 41% (Douglas fir). High aboveground base cation and Mn stocks indicate potential long-term threats to forest nutrition if trees are harvested. However, in Douglas fir stands, nutr

As a response to the increased pressure of global climate change on most ecosystems, national and international agreements aim at creating forests that are productive, resilient to climate change, and that store carbon to mitigate global warming. However, these aims are being challenged by increased tree mortality rates and decreased tree growth rates in response to increased incidence of extreme drought events. These phenomena make us aware of a lack of crucial insights into the effects of forest management on the growth and survival of trees, and on carbon storage in both trees and forest soils under increased incidence of drought. Here we compile current knowledge on how forest management and drought impact on tree growth and survival, and above- and belowground carbon storage in forest ecosystems. Based on this, we propose that climate-smart forestry may benefit from controlling stand density at intermediate levels (>60%, e.g.∼80%) by applying low levels of tree harvest intensity on a regular base. Furthermore, we propose that the actual optimal density will depend on the tree species, site conditions and management history. As a next step, studies are needed that take an above- and belowground approach and combine forest experiments with mechanistic models on water, carbon and nutrient flows in trees and soils within forests in order to transform current results, which focus on either soil or trees and are often highly-context dependent, to a more generic forest framework. Such a generic framework would be needed to enhance understanding across forest ecosystems on how forest management may promote forest resilience, productivity and carbon storage with increasing drought.

Monetary policy is the process by which the central bank attempts to maintain price stability. Typically, this is done by manipulating the interest rate. This process is executed by the central bank of a country or union. Specifically, the policy makers of a central bank make policy decisions manually, based on advise and experience. The process, of manipulating a variable to get the desired outcome, is a technology where system and control engineers are specialized in. Mostly, they focus on dynamical technological processes. Nevertheless, a new field in system and control theory pledges to widen this variety. Specifically, towards applying these system and control theories to economic processes: Economic engineering. Up to now, very little attention is paid to the possibility of applying system and control theory to monetary policy. This work combines the current model of the European Central Bank (ECB), used to analyze monetary policy in the Eurozone, and the economic-engineering analog that can be used to model economics as if it were a mechanical system. It builds on these two theories by presenting monetary policy as a control problem. Firstly, the analog is extended in order to express money and interest in mechanical terms. With this extension, a first-principles model of the economy is developed. The results of the ECB’s model are analyzed and an alternative is offered by the application of open loop transfer function characteristics. A PID controller is designed and the design conditions are interpreted as policy decisions. Finally, the effects of these design conditions are explained. The model, developed in this thesis, adds to existing models because of its distinction between disturbances and the control input. This contrasts the existing models because they approach both disturbances and control input similar - i.e. so called shocks. The first-principles modeling approach offers the first model that presents the underlying dynamics of the system. These, Mechanical Engineering | Systems and Control