Modelos de crecimiento y producción en España: historia, ejemplos contemporáneos y perspectivas

En el presente trabajo se presenta una revisión sobre los modelos forestales desarrollados en España durante los últimos años, tanto para la producción maderable como no maderable y, para la dinámica de los bosques (regeneración, mortalidad). Se presentan modelos tanto de rodal completo como de clases diamétricas y de árbol individual. Los modelos desarrollados hasta la fecha se han desarrollado a partir de datos procedentes de parcelas permanentes, ensayos y el Inventario Forestal Nacional. En el trabajo se muestran los diferentes submodelos desarrollados hasta la fecha, así como las plataformas informáticas que permiten utilizar dichos modelos. Se incluyen las principales perspectivas de desarrollo de la modelización forestal en España.In this paper we present a review of forest models developed in Spain in recent years for both timber and non timber production and forest dynamics (regeneration, mortality). Models developed are whole stand, size (diameter) class and individual-tree. The models developed to date have been developed using data from permanent plots, experimental sites and the National Forest Inventory. In this paper we show the different sub-models developed so far and the friendly use software. Main perspectives of forest modeling in Spain are presented.The models described in this paper were funded by different regional, national and European projects, and some of them were elaborated by the authors. This work was funded by the Spanish Government by the SELVIRED network (code AGL2008-03740) and the strategic project «Restauración y Gestión Forestal» (code PSE-310000-2009-4)

Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect

The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies.Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effectpublishedVersio

Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect

The increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies

Forest Biodiversity Assessment in Peruvian Andean Montane Cloud Forest

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as rega rds biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the ?Bosque de Neblina de Cuyas?, in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity

Modelo de crecimiento individual para Pinus silvestris, con datos de los Inventarios Forestales Nacionales 2º y 3º, en la provincia de Madrid

Se presenta un modelo de crecimiento individual en área basimétrica, construido a partir de los datos de las parcelas permanentes de los Inventarios Forestales Nacionales Segundo y Tercero. El incremento del área basimétrica se calcula para cada árbol por comparación de los diámetros medidos en ambos inventarios. Las variables independientes que intervienen en el modelo se pueden dividir en tres grupos: variables que explican la situación inicial del árbol (tamaño, competencia, etc.), variables que caracterizan la calidad de estación (pendiente, orientación, tipo de suelo�) y variables descriptoras de la masa, tales como el área basimétrica eliminada entre ambos inventarios, el área basimétrica remanente y la altura dominante, etc. Se evita el uso de la edad como variable independiente, puesto que el objetivo es que el modelo de crecimiento pueda servir tanto para masas regulares como para masas irregulares. La metodología descrita, que en el trabajo se aplica a Pinus sylvestris L., en la provincia de Madrid, permite la creación de modelos similares a partir de los datos del Inventario Forestal Nacional

Actualización de los volúmenes proporcionados por los Inventarios Forestales Nacionales

Para monitorizar el estado y los cambios en los recursos forestales, organizaciones internacionales, tales como FAO o UNFCCC, solicitan información a los distintos países. Entre los parámetros solicitados uno de los más habituales es el volumen forestal. Para dar respuesta a los requerimientos la mayoría de los países utilizan los datos de sus Inventarios Forestales Nacionales (IFN). Sin embargo, dada la creciente frecuencia en la demanda de información, que en algunos casos llega a ser anual, existen discrepancias temporales entre las fechas de los IFN y de los datos requeridos. Para solventar dichas diferencias algunos países recurren a modificar los protocolos de medición para contar con datos anuales a nivel nacional, mientras otros recurren a la actualización de los datos mediante modelos. En cualquiera de los casos es necesaria una metodología específica para proporcionar estimaciones adecuadas con un error aceptable. En este trabajo se presentan dos metodologías diferentes. La primera de ellas es la utilizada en Estados Unidos donde se toman datos anualmente en todo el país. La segunda metodología permite actualizar los volúmenes medidos en el IFN español, con periodo de remedición de 10 años. Se hace especial hincapié en describir la metodología española, la cual se basa en la modelización del balance anual del volumen en las parcelas del IFN, y en la estimación de valores medios y la incertidumbre asociada (intervalos de confianza) mediante técnicas de inferencia híbrida. Se destacan en todos los casos la importancia del uso de imágenes provenientes de sensores remotos como información auxiliar

Revisión de índices de distribución espacial usados en inventarios forestales y su aplicación en bosques tropicales

En este trabajo se hace una revisión de los diferentes índices utilizados para describir y caracterizar la estructura horizontal o patrón espacial en masas forestales con especial énfasis en aquellos que se han aplicado para el estudio de bosques tropicales. Estos índices se han clasificado en función del tipo de datos requerido para su cálculo. Diferentes aspectos del comportamiento estadístico y la aplicabilidad de aquellos índices más usados (los índices de Fisher y Morisita, el análisis de la varianza en escalas anidadas y la técnica SADIE de entre las técnicas que utilizan datos de densidades o coberturas en unidades de muestreo; los índices de Clark-Evans, Pielou y Byth-Ripley basados en medidas de distancias entre árboles; y las funciones L(d) y Oring que requieren para su cálculo la posición de todos los arboles) se analizan en un caso de estudio a partir de datos de parcelas experimentales un bosque tropical andino

Productivity Estimations for Monospecific and Mixed Pine Forests along the Iberian Peninsula Aridity Gradient

National Forest Inventories (NFIs) are the primary source of information to fulfill international requirements, such as growing stock volume. However, NFI cycles may be “out of phase” in terms of the information required, so prediction techniques are needed. To disentangle the effects of climate and competition on stand productivity and to estimate the volume of stocks at national scale, it is important to recognize that growth and competition are species-specific and vary along climatic gradients. In this study, we estimate the productivity of five pine species (Pinus sylvestris, Pinus pinea, Pinus halepensis, Pinus nigra and Pinus pinaster), growing in monospecific stands or in mixtures along an aridity gradient in the Iberian Peninsula, based on Spanish NFI data. We study the stand volume growth efficiency (VGE), since it allows the comparison of volume growth in monospecific and mixed stands. The results reveal the importance of considering the aridity when assessing VGE. Moreover, it was found that, in general, admixture among pine species leads to modifications in the VGE, which can vary from negative to positive effects depending on species composition, and that this is always influenced by the aridity. Finally, we provide simple growth efficiency models for the studied pines species which are valid for both monospecific and mixed stands along the aridity gradient of the Iberian Peninsula

El uso del escáner láser aerotransportado para la estimación de la biomasa foliar del "Pinus sylvestris" L. en Canencia (Madrid)

La estimación de la biomasa foliar es uno de los problemas actuales que se presenta en los inventarios forestales, entre otras razones por su relación con la fijación del carbono atmosférico, y consecuentemente con la disminución del efecto invernadero. Para poder llevar a cabo una estimación adecuada de la biomasa foliar es necesario recurrir a un muestreo destructivo, que requiere el apeo de los árboles, la separación de cada uno de sus componentes así como el pesaje de los mismos. Para el cálculo de la biomasa foliar por unidad de superficie, se suelen crear modelos que relacionan la biomasa foliar del árbol con variables de fácil medición en los inventarios forestales, tales como el diámetro normal. Generalmente no se emplean en estos modelos otras variables que también están altamente correlacionadas, como la altura de copa o el diámetro de la copa, ya que dificultan la utilización posterior del modelo resultante. Mediciones obtenidas a partir de un escáner láser aerotransportado (lidar), y su alta correlación con valores de biomasa foliar por unidad de superficie, permiten el cálculo de la biomasa foliar en superficies extensas sin necesidad de la realización de un inventario exhaustivo. En este trabajo se presenta un modelo que permite la obtención de un mapa de la biomasa foliar a partir del sensor lidar en masas de Pinus sylvestris L. en Canencia (Madrid)

Species admixture can increase potential tree growth and reduce competition

11 Pág.Trees often show better growth in mixed as opposed to monospecific neighborhoods as consequence of competition reduction and facilitation between species. However, it can be challenging to discern the effect of these factors as they occur simultaneously, so often they are jointly refereed as complementarity. By using tree growth models based on potential tree growth reduced by a competition modifier and including species mixing effects on both components (potential tree growth and competition modifier), we aim to verify that tree potential growth is modified by admixture, which may provide further information on species interactions and complementarity. We used tree data from the Spanish National Forest Inventory, selecting plots located in two different mixtures, Scots pine – European beech and Scots pine – Oak mixtures, as well as in the corresponding monospecific stands of those species. To analyse whether the species mixture increases the potential basal area growth, we developed linear mixed quantile regressions to model the potential growth, while to analyse the competition reduction we developed linear mixed models. We include the Martonne aridity index as a measure of the site conditions in the models to explore whether climate conditions modify the effects of species mixture. Our results show a slight effect of the mixture on the potential basal area growth of pine while the potential growth of beech clearly benefited from the pine/beech mixtures. For the pine/oak mixtures the potential growth of both species was higher in mixtures than in monospecific stands. Moreover, we found a positive influence of humidity on potential growth for all the species and mixtures, although the magnitude of the effect was less important for beech and more notable in the case of the pine/oak mixtures. We also found that for the studied species, admixed species reduced competition, with lower inter-specific than intra-specific competition effects, and that these effects were mediated by climate conditions. We concluded that the potential tree basal area growth is influenced by the species admixture, which suggest that species mixing effects can be relevant also under low stand densities. Our results highlight the importance of integrating the effect of species interactions on both the potential growth of trees and the competition modifier when the aim of the research is to further our understanding of species interactions.This study was supported by the Spanish Ministerio de Ciencia e Innovación, project PID2021- 821 126275OB-C21/C22.Peer reviewe