Development of a dynamic stand growth model and optimization of the management of Pinus pinaster Ait. in Asturias

This dissertation comprises three studies that provide tools for improving the manage- ment of maritime pine (Pinus pinaster Ait.) stands in Asturias (NW Spain). The studies were based on information derived from two networks of research plots established in stands of this species in the region. In Study I, several age-independent methods were evaluated for site index estimation and height growth prediction, as information about stand age is not always collected in forest inventories. The growth intercept method proved the best for estimating site index, while an age-independent equation that uses climatic variables as predictors behaved the best for height growth prediction. In the absence of age data, these methods can be used to provide the input information re- quired by the dynamic stand growth model developed in Study II. In this model, it was assumed that the state of a stand at any age can be described by dominant height, num- ber of stems per hectare and stand basal area, which can be projected to any other age by using transition functions. Two alternative procedures can be used to estimate total and merchantable volumes from these state variables: a stand volume ratio function or a disaggregation system. The former proved the best method as it is more accurate and computationally more e cient. In addition, comparison of the whole model with those developed for the nearby regions of Galicia and northern Portugal showed that a single model may su ce for the entire NW the Iberian Peninsula. Using the developed model and an optimization algorithm, Study III optimized the stand-level management of the species in Asturias in economic terms, considering the number, timing and intensity of thinning operations, as well as the rotation age as decision variables. The depth- rst search (DFS) method was initially used to compare the stand volume ratio function and the disaggregation system: both provided similar results, although the former was computationally more e cient and was therefore selected for further optimizations. The DFS and ve direct search optimization methods (one based on one solution vector and four on a population of solution vectors) were then compared using a xed discount rate. The di erential evolution method produced the most consistent results and it was used to evaluate the e ect of site quality, stem density and discount rate on optimal management schedules. In general, three heavy thinning operations were considered in the optimal schedule. As site quality and discount rate increased, the optimal timing of cutting occurred earlier, while stem density was not in uent

Fitting and calibrating a multilevel mixed-effects stem taper model for maritime pine in NW Spain

Stem taper data are usually hierarchical (several measurements per tree, and several trees per plot), making application of a multilevel mixed-effects modelling approach essential. However, correlation between trees in the same plot/stand has often been ignored in previous studies. Fitting and calibration of a variable-exponent stem taper function were conducted using data from 420 trees felled in even-aged maritime pine (Pinus pinaster Ait.) stands in NW Spain. In the fitting step, the tree level explained much more variability than the plot level, and therefore calibration at plot level was omitted. Several stem heights were evaluated for measurement of the additional diameter needed for calibration at tree level. Calibration with an additional diameter measured at between 40 and 60% of total tree height showed the greatest improvement in volume and diameter predictions. If additional diameter measurement is not available, the fixed-effects model fitted by the ordinary least squares technique should be used. Finally, we also evaluated how the expansion of parameters with random effects affects the stem taper prediction, as we consider this a key question when applying the mixed-effects modelling approach to taper equations. The results showed that correlation between random effects should be taken into account when assessing the influence of random effects in stem taper predictionThe corresponding author was in receipt of an FPU grant (AP2012-05337) from the Spanish Ministry of Education, Culture and Sport, http://www.mecd.gob.es/. This work was also supported by project no. AGL2008-02259/FOR from the Spanish Ministry of Science and Innovation, http://www.idi.mineco.gob.es/; and project nos. CN-07-094 and SVPA-13-ECOEMP-58 from the Government of the Principality of Asturias, http://www.asturias.es/S

Fitting and Calibrating a Multilevel Mixed-Effects Stem Taper Model for Maritime Pine in NW Spain

[EN] Stem taper data are usually hierarchical (several measurements per tree, and several trees per plot), making application of a multilevel mixed-effects modelling approach essential. However, correlation between trees in the same plot/stand has often been ignored in previous studies. Fitting and calibration of a variable-exponent stem taper function were conducted using data from 420 trees felled in even-aged maritime pine (Pinus pinaster Ait.) stands in NW Spain. In the fitting step, the tree level explained much more variability than the plot level, and therefore calibration at plot level was omitted. Several stem heights were evaluated for measurement of the additional diameter needed for calibration at tree level. Calibration with an additional diameter measured at between 40 and 60% of total tree height showed the greatest improvement in volume and diameter predictions. If additional diameter measurement is not available, the fixed-effects model fitted by the ordinary least squares technique should be used. Finally, we also evaluated how the expansion of parameters with random effects affects the stem taper prediction, as we consider this a key question when applying the mixed-effects modelling approach to taper equations. The results showed that correlation between random effects should be taken into account when assessing the influence of random effects in stem taper predictionSIThe corresponding author was in receipt of an FPU grant (AP2012-05337) from the Spanish Ministry of Education, Culture and Sport, http://www.mecd.gob.es/. This work was also supported by project no. AGL2008-02259/FOR from the Spanish Ministry of Science and Innovation, http://www.idi.mineco.gob.es/; and project nos. CN-07-094 and SV-PA-13-ECOEMP-58 from the Government of the Principality of Asturias, http://www.asturias.es/

Using density management diagrams to assess crown fire potential in Pinus pinaster Ait. stands

[EN] Context: Density management diagrams (DMDs) are useful for designing, displaying and evaluating alternative density management regimes for a given stand-level management objective. The inclusion of variables related to crown fire potential within DMDs has not previously been considered. Aims: The aim of this study was to include isolines of variables related to crown fire initiation and spread in DMDs to enable identification of stand structures associated with different types of wildfire. Methods: Biometric and fuel data from maritime pine (Pinus pinaster Ait.) stands in NW Spain were used to construct DMDs. Different surface and crown fire behaviour models were used together to estimate crown fire potential. Results: The crown fire potential varied greatly throughout development of the maritime pine stands. Low stands were more prone to crowning. The type of crown fire was mainly determined by stand density. Conclusion: The DMDs developed can be used to identify relationships between stand structure and crown fire potential, thus enabling the design of thinning schedules aimed at reducing the likelihood of crowning. © 2013 INRA and Springer-Verlag FranceSIFunding for this research was provided by the Spanish Min- istry of Science and Innovation, project no. AGL2008-02259/FOR

Modeling diameter distributions in radiata pine plantations in Spain with existing countrywide LiDAR data

[EN] Key message: We evaluated the use of low-density airborne laser scanning data to estimate diameter distributions in radiata pine plantations. The moment-based parameter recovery method was used to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. The fitted models explained more than 77% of the observed variability. This approach can be replicated every 6 years (temporal cover planned for countrywide LiDAR flights in Spain). Context: The estimation of stand diameter distribution is informative for forest managers in terms of stand structure, forest growth model inputs, and economic timber value. In this sense, airborne LiDAR may represent an adequate source of information. Aims: The objective was to evaluate the use of low-density Spanish countrywide LiDAR data for estimating diameter distributions in Pinus radiata D. Don stands in NW Spain. Methods: The empirical distributions were obtained from 25 sample plots. We applied the moment-based parameter recovery method in combination with the Weibull function to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. We evaluated the results by using the Kolmogorov–Smirnov (KS) test and a classification tree and random forest (RF) to relate the KS test result for each plot to stand-level variables. Results: The models used to estimate average (dm) and quadratic (dg) mean diameters from LiDAR metrics, required for recovery of the Weibull parameters, explained a high percentage of the observed variance (77 and 80%, respectively), with RMSE values of 3.626 and 3.422 cm for the same variables. However, the proportion of plots accepted by the KS was low. This poor performance may be due to the strictness of the KS test and/or by the characteristics of the LiDAR flight. Conclusion: The results justify the assessment of this approach over different species and forest types in regional or countrywide surveys.S

Modelling diameter distributions in radiata pine plantations in Spain with existing countrywide LiDAR data

We evaluated the use of low-density airborne laser scanning data to estimate diameter distributions in radiata pine plantations. The moment-based parameter recovery method was used to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. The fitted models explained more than 77% of the observed variability. This approach can be replicated every 6 years (temporal cover planned for countrywide LiDAR flights in Spain). Context: The estimation of stand diameter distribution is informative for forest managers in terms of stand structure, forest growth model inputs, and economic timber value. In this sense, airborne LiDAR may represent an adequate source of information. Aims: The objective was to evaluate the use of low-density Spanish countrywide LiDAR data for estimating diameter distributions in Pinus radiata D. Don stands in NW Spain. Methods: The empirical distributions were obtained from 25 sample plots. We applied the moment-based parameter recovery method in combination with the Weibull function to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. We evaluated the results by using the Kolmogorov–Smirnov (KS) test and a classification tree and random forest (RF) to relate the KS test result for each plot to stand-level variables. Results: The models used to estimate average (dm) and quadratic (dg) mean diameters from LiDAR metrics, required for recovery of the Weibull parameters, explained a high percentage of the observed variance (77 and 80%, respectively), with RMSE values of 3.626 and 3.422 cm for the same variables. However, the proportion of plots accepted by the KS was low. This poor performance may be due to the strictness of the KS test and/or by the characteristics of the LiDAR flight. Conclusion: The results justify the assessment of this approach over different species and forest types in regional or countrywide surveys.Spanish Ministry of Science and Innovation (AGL2008-02259/FOR); Galician Government, Xunta de Galicia, Dirección Xeral de Montes (09MRU022291PR); Norvento (Multinational energy company) (PGIDT09REM023E); Eduardo González-Ferreiro was financially supported by the Plan galego de investigación, innovación e crecemento 2011-2015 (Plan I2C) (Official Journal of Galicia – DOG nº 52, 17/03/2014 p. 11343, exp: POS-A/2013/049): Galician Government (Dirección Xeral de Ordenación e Calidade do Sistema Universitario de Galicia – Consellería de Educación e Ordenación Universitaria) and European Social Fund. Manuel Arias-Rodil was financially supported by an FPU grant (AP2012-05337) from the Spanish Ministry of Education.Spanish Ministry of Science and Innovation (AGL2008-02259/FOR); Eduardo González-Ferreiro was financially supported by the Plan galego de investigación, innovación e crecemento 2011-2015 (Plan I2C) (Official Journal of Galicia - DOG nº 52, 17/03/2014 p. 11343, exp: POS-A/2013/049) - Galician Government (Dirección Xeral de Ordenación e Calidade do Sistema Universitario de Galicia - Consellería de Educación e Ordenación Universitaria) and European Social Fund. Manuel Arias-Rodil was financially supported by an FPU grant (AP2012-05337) from the Spanish Ministry of Education.S

Modeling post-fire mortality in pure and mixed forest stands in Portugal—A forest planning-oriented model

Assessing impacts of management strategies may allow designing more resistant forests to wildfires. Planning-oriented models to predict the effect of stand structure and forest composition on mortality for supporting fire-smart management decisions, and allowing its inclusion in forest management optimization systems were developed. Post-fire mortality was modeled as a function of measurable forest inventory data and projections over time in 165 pure and 76 mixed forest stands in Portugal, collected by the 5th National Forest Inventory plots (NFI) plus other sample plots from ForFireS project, intercepted within 2006–2008 wildfire perimeters’ data. Presence and tree survival were obtained by examining 2450 trees from 16 species one year after the wildfire occurrence. A set of logistic regression models were developed under a three-stage modeling system: firstly multiple fixed-effects at stand-level that comprises a sub-model to predict mortality from wildfire; and another for the proportion of dead trees on stands killed by fire. At tree-level due to the nested structure of the data analyzed (trees within stands), a mixed-effect model was developed to estimate mortality among trees in a fire event. The results imply that the variation of tree mortality decreases when tree diameter at breast height increases. Moreover, the relative mortality increases with stand density, higher altitude and steeper slopes. In the same conditions, conifers are more prone to die than eucalyptus and broadleaves. Pure stands of broadleaves exhibit noticeably higher fire resistance than mixed stands of broadleaves and others species compositionThis research was supported by Project UID/AGR/00239/2013, PTDC/AGR-CFL/64146/2006 “Decision support tools for integrating fire and forest management planning” and project FIRE-ENGINE “Flexible Design of Forest Fire Management Systems” (MIT/FSE/0064/2009), both funded by the Portuguese Science Foundation (FCT), and contributes to the activities of the ALTERFOR Project “Alternative models and robust decision-making for future forest management”—H2020-ISIB-2015-2/grant agreement No. 67654, funded by European Union Seventh Framework Programme. This research has received also funding from the European Union’s H2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 691149 (SuFoRun). The authors would like to thank the Portuguese Science Foundation for funding the doctoral scholarships of Brigite Botequim (SFRH/ BD/44830/2008) and the Post Doc grant SFRH/BPD/96806/2013 of Susete Marques. Researcher Jordi Garcia-Gonzalo was supported by a “Ramon y Cajal” research contract from the MINECO (Ref. RYC-2013-14262) and has received funding from CERCA Programme / Generalitat de Catalunya. In addition, the authors wish to acknowledge the Portuguese Forest Service (ICNF) for supplying the perimeters of wildfires and NFI Databases and ForFireS Project for providing the inventory DatabasesS

Development of a stem taper function using mixed-effects models for Pinus sylvestris in Turkey: selection of fixed parameters to expand

[ES] Las funciones de perfil predicen la variación del diámetro a lo largo del tronco del árbol, y se emplean, principalmente, para desarrollar tarifas de cubicación con clasificación de productos. En este trabajo se desarrolló una función de perfil para Pinus sylvestris en Turquía empleando la metodología de modelos mixtos, donde algunos parámetros del modelo incluyen una parte fija (común a toda la población) y un efecto aleatorio (específico para cada individuo). Se analizaron diferentes estrategias para seleccionar la mejor combinación de parámetros fijos a expandir con efectos aleatorios (parámetros de efectos mixtos): (1) aquellos parámetros fijos que presentaron mayor variabilidad y (2) todas las posibles combinaciones de uno y dos parámetros de efectos mixtos, resultando esta última más adecuada. Dado que la inclusión de efectos aleatorios no fue suficiente para considerar la autocorrelación de residuos, se modelizó la matriz de varianza-covarianza del término de error mediante una estructura autorregresiva de primer orden. También se evaluó la respuesta calibrada (estimación de los efectos aleatorios para un nuevo individuo) utilizando un diámetro medido a distintas alturas a lo largo del tronco. El modelo mixto seleccionado presentó los mejores resultados en las fases de ajuste y de calibración. En general, se recomienda emplear el modelo mixto si se dispone de una medición adicional del diámetro del tronco a una altura de entre 40-90 % de la altura total del árbol. En caso contrario, desde un punto de vista predictivo resulta más conveniente emplear el modelo ajustado por mínimos cuadrados ordinarios[EN] Stem taper functions predict diameter variation along the tree stem, enabling to estimate merchantable volume according to market requirements. In this study, a stem taper function for Pinus sylvestris in Turkey was developed using the mixed-effects modelling approach, which allows some parameters to include a fixed part (common to the whole population) and a random effect (individual-specific response). We analyzed different strategies to choose the best combination of fixed parameters to expand with random effects (mixed-effects parameters): (1) expanding fixed parameters that presented the highest variability and (2) all possible combinations of one and two mixed-effects parameters; the best performance was observed in the latter. Given that inclusion of random effects was not enough to account for the existing correlation between the residuals of the same individual, the variance-covariance matrix of the error term was modelled by a first-order autoregressive structure. In addition, we evaluated the response obtained by calibration (estimation of random effects for a new individual), i.e. using a diameter measured at different heights along the stem. The selected mixed-effects model presented the best results both in the fitting and calibration steps. Generally, the mixed-effects model is recommended if an additional stem diameter measurement at 40-90 % of the total tree height is available. Otherwise, and from a predictive point of view, the model fitted by non-linear ordinary least squares is recommended, which only considers fixed parametersSIFinanciación por parte del Fondo Social Europeo y del gobierno de España a través del INIA y del Ministerio de Educación, Cultura y Deporte (ayuda FPU, AP2012-05337). El grupo de investigación UXFS está parcialmente financiado por la Xunta de Galicia, España, a través del Programa de Consolidación y Estructuración de Unidades de Investigación Competitivas 2014-201

The COVID-19 pandemic effect on the prehospital Madrid stroke code metrics and diagnostic accuracy

Background Only very few studies have investigated the effect of the COVID-19 pandemic on the prehospital stroke code protocol. During the first wave, Spain was one of the most affected countries by the SARS-CoV-2 coronavirus disease pandemic. This health catastrophe overshadowed other pathologies, such as acute stroke, the leading cause of death among women and the leading cause of disability among adults. Any interference in the stroke code protocol can delay the administration of reperfusion treatment for acute ischemic strokes, leading to a worse patient prognosis. We aimed to compare the performance of the stroke code during the first wave of the pandemic with the same period of the previous year. Methods This was a multicentre interrupted time-series observational study of the cohort of stroke codes of SUMMA 112 and of the ten hospitals with a stroke unit in the Community of Madrid. We established two groups according to the date on which they were attended: the first during the dates with the highest daily cumulative incidence of the first wave of the COVID-19 (from February 27 to June 15, 2020), and the second, the same period of the previous year (from February 27 to June 15, 2019). To assess the performance of the stroke code, we compared each of the pre-hospital emergency service time periods, the diagnostic accuracy (proportion of stroke codes with a final diagnosis of acute stroke out of the total), the proportion of patients treated with reperfusion therapies, and the in-hospital mortality. Results SUMMA 112 activated the stroke code in 966 patients (514 in the pre-pandemic group and 452 pandemic). The call management time increased by 9% (95% CI: -0.11; 0.91; p value = 0.02), and the time on scene increased by 12% (95% CI: 2.49; 5.93; p value = <0.01). Diagnostic accuracy, and the proportion of patients treated with reperfusion therapies remained stable. In-hospital mortality decreased by 4% (p = 0.05). Conclusions During the first wave, a prolongation of the time “on the scene” of the management of the 112 calls, and of the hospital admission was observed. Prehospital diagnostic accuracy and the proportion of patients treated at the hospital level with intravenous thrombolysis or mechanical thrombectomy were not altered with respect to the previous year, showing the resilience of the stroke network and the emergency medical serviceNRL, Order HAC/667/2020, Foundation for Biosanitary Research and Innovation in Primary Care (FIIBAP