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The most interesting factors associated with seed and cone production of Aleppo pine were largely reviewed to identify broad patterns and potential effectiveness of reforestation efforts and planning. Aleppo pine cone production and seed yields are relatively variable, with differences between spatial and temporal influences. These differences are considered, mainly between (i) year, (ii) stand characteristics and (iii) individual tree measurements. Annual variability among populations was recorded for cone production per tree, based on influencing factors such as genetic characteristics, wetness, nutrient availability, insect pests and disease. In addition, some factors may affect Aleppo pine tree growth directly but may be affecting seed and cone production indirectly. Therefore, reduced stand density results in less competition among Aleppo pine trees and accompanying understory flora, which subsequently increases the stem diameter and other tree dimensions, including seed production. This review suggests that reforestation planning, particularly thinning, will result in improved tree morphology that will increase Aleppo pine seed and cone crops. Wildfire intensity and stand conditions such as light and soil nutrient status are also examined.

In Tunisia, the Aleppo pine seed has a great importance, since in the last decades human consumption has risen considerable. Thus its regeneration and seed production capacities are important factors to take into account to reach the necessities of the country. To study the production of cones and seeds of Aleppo pine, Tunisia's native Aleppo pine forests were surveyed in summer 2006, using 79 plots (40 × 25 m: 1,000 m²) spread over four bioclimatic zones. Stand and tree characteristics, crown dimensions and cone/seed variables were measured from an average tree of each plot (i.e. a total of 79 trees). Recorded data were submitted to simple and multiple regression analyses for explaining the variability in crown volume and crown surface, cone number and seed yield per average tree. Results showed a negative correlation between the stand density, crown characteristics and number of cones and seeds harvested from the average tree. For crown volume and surface, age, stand density, tree height, diameter at breast height, crown diameter and crown height were important explanatory variables under multiple regression analyses. For cone number per tree, only the age, stand density and total height were the most determinant variables. Matures cone number per tree and cone mass per tree were the most informative parameters for the total seed yields per tree. Finally, forest managers should know that crown size affects cone and seed crop of the Aleppo pine individual tree grown in Tunisia, but has no effects on seed number per cone and seed mass per cone.Key words: Aleppo pine; crown dimensions; cone number; seed yields; bioclimatic zones; Tunisia. ResumenVariables de parcela, árbol y copa que afectan la producción de piñas y piñones en bosques de pino carrasco de Túnez En Túnez, la producción de piñones del pino carrasco tiene una gran importancia, ya que en las últimas décadas su consumo ha aumentado de forma considerable. Por ello, su regeneración y capacidad de producción de piñas/piñones en un factor a tener en cuenta en Túnez. En verano del 2006 se eligieron 79 parcelas de 1.000 m² (40 × 25 m) situadas en cuatro zonas bioclimáticas representativas de Túnez para el estudio de la capacidad de producción de piñas/piñones del pino carrasco. Teniendo en cuenta todos los árboles de las parcelas, se identificó el árbol promedio, del que posteriormente se medirían variables de árbol, dimensión de copa y producción de piñas/piñones. Los resultados demuestran una correlación negativa entre la densidad de la parcela, características de la copa y el número de piñas/piñones recolectados por cada árbol promedio. Para la descripción del volumen y superficie de copa, las variables más importantes fueron edad, densidad de parcela, altura y diámetro del árbol, y altura y diámetro de la copa. Las variables edad, densidad de parcela y altura del árbol fueron las más significativas para la determinación de nú-mero de piñas por árbol. Para el cálculo del total de piñones por árbol, las variables más informativas fueron el nú-mero ...

Aleppo pine had a large forest cover in North Africa and along the Mediterranean basin which management is not fully developed and new forest tools are required. In this research, the forest structure, epidometric characteristics and allometric relationships were studied in 79 plots covering four bioclimatic zones from natural even aged forests of Aleppo pine located between eastern Algeria to the western coastal part of Tunisia. To characterize the forest structure three sampling methods were carried out: classical inventories (recording all pine trees), and two simplified approach using one average size or five dominant pine tree per plot. Annual growth increment and cone production were only calculated for the average size tree. Furthermore, the analysis of variance showed non-significant differences recorded between bioclimatic zones in trunk or crown diameter using the two simplified approach. Moreover, a significant decrease from wetter to drier areas in total height, crown height, cone seed production was observed only for average size tree method. However, the analysis of covariance showed significant differences between both approaches in total height, trunk diameter and crown coverage which were largely influenced by the pine tree density. In future investigations, we confirmed previous research that the dominant tree is a good sampling method to examine the site fertility, whereas the average size tree constitutes a valuable approach to study the population growth and reproduction.Key words: Pinus halepensis Mill.; bioclimatic zones; forest structure; sampling approach; increment; reproductive characteristics. ResumenMétodos alternativos de muestreo para estimar la estructura y caracteres reproductivos de bosques de pino carrasco en Túnez El pino carrasco muestra una gran cobertura forestal, tanto en el norte de África como en toda la Cuenca Mediterránea, cuyo manejo no está totalmente desarrollado lo que requiere nuevas herramientas de manejo. En esta investigación, se estudiaron la estructura forestal, las características epidométricas y las relaciones alométricas de 79 parcelas distribuidas a lo largo de cuatro zonas bioclimáticas en bosques regulares de pino carrasco situados entre el este de Argelia y la costa este de Túnez. Para caracterizar la estructura forestal se aplicaron tres métodos de muestreo: inventario clásico (midiendo todos los pies) y dos propuestas más sencillas, usando un árbol medio o cinco pies dominantes por parcela. El análisis de varianza no mostraba diferencias significativas de las mediciones de diámetro de tronco y de copa realizadas entre las distintas zonas bioclimáticas usando ambos métodos. Por otra parte, se observó una disminución significativa de las zonas más húmedas a las más secas en altura toral, altura de copa y producción de semillas fue observada aplicando el método de árbol medio. Además, el análisis de covarianzas mostraba diferencias significativas, usando ambas metodologías, en los valores medios de altura total, diámetro de tronco y cobertura de...

About 50 years ago (in the 1960’s), 30 Tunisian Aleppo pine provenances were planted in Korbus arboretum (NE of Tunisia). For this study, only twelve provenances were selected and assessed. The selected provenances were evaluated for seed production, tree height and diameter. Results showed high inter-provenance variability for all the traits considered. However, within this site, the produced overall Aleppo pine cones per tree was less than the half in comparison to the interior forest of the country. Similarly, the average produced cone was lighter with less seeds content compared to non maritime coastal forests. The developed mature cones per tree in terms of number and weight were the major factors influencing seed yield within the site.