Morphological characteristics and variation of wood, cone and seed productions in the reforestation of Aleppo pine in Northeastern Tunisia using terrestrial and spatial index approaches

Abstract

For several decades, forest management policies have encouraged land cover changes, with the establishment of tree cover such as Aleppo pine in natural or degraded ecosystems for soil protection and the firewood production. In order to investigate the importance of Aleppo pine trees in the ecosystem, this study was conducted in the reforestation of the Aleppo pine of Northeastern Tunisia. The production of wood, cones and seeds of Aleppo pine in the 6 date reforestation in Northeastern Tunisia were surveyed using 6 plots (20 tree/plot) spread over 6 different location. Our hypothesis was to determine the characteristics that can be decisive in estimating the production of Aleppo pine in reforestation in Tunisia using terrestrial and spatial measurements including (i) age, (ii) dendrometric characteristics, (iii) silvicultural treatments, (iv) stationary data and/ or (v) remote sensing parameter (NDVI: Normalized Difference Vegetation Index). We found that the Aleppo pine in Northeastern Tunisia and at young age trees (14–35 years) were more productive than the regeneration or reforestation stand, either young or old, in Northwest of Tunisia. Wood, cone and seed productions were significantly different amongst the plots (p <0.05). The NDVI was positively correlated with the production of wood, cones and seeds. Stand age, exposure and longitude were also positively correlated with the production. However, longitude and altitude were negatively correlated with the production, showing a negative effect on the morphological traits of trees and, subsequently, their growth. The regression analysis indicates that NDVI and age were the most determinant factors of seed production. This research suggests that reforestation planning, particularly the choice of altitude and latitude, may result in improved tree morphology that may increase Aleppo pine wood seed and cone crops.

Effect of Seed Extraction Period and Germination Temperature on Viability of Pinus patula Under Controlled Conditions

“…Previous studies have shown that both environmental and genetic factors influence the potential of trees to produce fertile quality seeds whereby depending on the tree species, seed germination varied according to latitude, elevation, soil moisture, soil nutrient, temperature, type and density of plant cover, and degree of habitat disturbance of the site [49,50]. Location of seed at the time of maturity plays an important role in determining a forest tree's potential for seed quality and seed fertility [51][52][53].…”

Influence of Cone Physical Characteristics and Extraction Exposure Period on Seed Yield of Pinus patula

“…Cone and seed production in other pines has also been shown to be positively influenced by larger basal areas [22,39]. Other factors such as stand density, climatic variations, and the morphological parameters of trees also influence their reproductive capacity [40][41][42]. It was reported that in some pines (for example Aleppo), sub-humid climate enhances cone production over semi-arid conditions.…”