Site index curves for natural Aleppo pine forests in the central Ebro valley (Spain)

Abstract

Site index curves were created for natural Aleppo pine (Pinus halepensis Mill.) stands in the Ebro Valley (northeastern Spain). Data were obtained from 54 felled dominant trees. The Generalized Algebraic Difference Approach (GADA) was used to fit 11 equations with a longitudinal data structure that included all possible growth intervals. Three statistical criteria were used for model comparison: root mean square error (RMSE), adjusted coefficient of determination (R2adj) and Akaike’s information criterion (AIC). Graphical evaluation of the data (plots of observed against predicted values and of residuals against predicted values) was also conducted. In addition, the root mean square error (RMSE) was plotted against age. Finally, fitted site index curves for different site qualities were superimposed on the profile plots of the stems analysed. The best reference age (60 years) was calculated from the relative error in the dominant height prediction. The Hossfeld IV model proved the most suitable for representing site index in the study area. Furthermore, only three site index curves (6, 10 and 14 m at 60 years) were suitable for classifying the entire study area because of the low productivity of the stands. These were compared with other site index curves developed for Spain and other countries, for the natural range of distribution of the species. Specific site index curves must be created for the study area, because the existing qualities and growth patterns are not well-represented in other models.

Temporal Transferability of Pine Forest Attributes Modeling Using Low-Density Airborne Laser Scanning Data

“…Explanatory variables included those related to tree size (diameter at breast height, total height), stand density (basal area, Hart-Becking index), dominant trees (dominant height, dominant diameter), competition (BALMOD) [57] and site quality (site index). Site index and dominant height evolution were estimated using the site index curves developed for natural Aleppo pine forests in the central Ebro valley [58].…”

Actas del XIX Congreso de Tecnologías de la Información Geográfica. TIG al servicio de los ODS Zaragoza, 12 a 14 de septiembre de 2022

“…Los datos de campo se armonizaron para el año 2011, en concordancia con el primer vuelo LiDAR, utilizando el modelo de árbol individual PHRAGON-2017 (Alonso, 2018), implementado a través de la plataforma de simulación Simanfor (Bravo et al, 2012), siguiendo el proceso metodológico expuesto en Domingo et al (2019). El cálculo del IS para cada parcela de muestreo se realizó utilizando las ecuaciones de altura dominante-edad para pino carrasco en el Valle del Ebro (Rojo-Alboreca et al, 2017), ajustadas mediante la metodología GADA (Castedo-Dorado et al, 2007), estableciendo la edad de referencia en los 60 años (Tabla 1).…”

“…El incremento de la disponibilidad de datos LiDAR multitemporales ha permitido el desarrollo de estudios que han probado la eficacia para ajustar las trayectorias o curvas de crecimiento en altura dominante-edad en masas monoespecíficas en Centroeuropa (Socha et al, 2017) o en pinares de Pinus pinaster en Galicia (Guerra-Hernández et al, 2021); así mismo, también se ha analizado cómo diferentes tamaños de celda influyen en el modelo de IS derivado (Socha et al, 2020). El IS medido en campo para la edad de referencia, que en el presente estudio se ha definido en 60 años (Rojo-Alboreca et al, 2017), se puede estimar utilizando datos LiDAR multitemporales mediante dos enfoques principales: indirecto y directo.…”

Modelling dominant height growth including a rainfall effect using the algebraic difference approach

“…The following base growth functions were used to generate candidate models for describing dominant height: Bertalanffy-Richards (Richards, 1959), Lundqvist-Korf (Korf, 1939), McDill-Amateis (McDill and Amateis, 1992), and Hossfeld I (Kiviste et al, 2002). These functions are widely used in forest research and they are reported to be flexible in modelling stand growth attributes, including dominant height (Rojo Alboreca et al, 2017;Sánchez-González et al, 2005;Tahar et al, 2012). The ADA technique was used in this study to demonstrate the concept of incorporating rainfall into the model in the context of South Africa.…”