Cupressus dupreziana A. Camus: distribution, decline and regeneration on the Tassili n'Ajjer, Central Sahara As soon as it was first discovered in 1924, on the heights of the Tassili n'Ajjer, Cupressus dupreziana (A. Camus) was declared an endangered species. The few ancient trees to be seen in the beds of wadis gave reason to suppose that they were isolated individuals left behind from a forest that had flourished in a damper climate. Attempts at a census of the trees were made on a number of occasions, the fullest, in 1972, reporting a total of 230 living specimens. The revision of this inventory between 1997 and 2001 has now enabled us to draw the boundaries of the present range of this species, to assess its rate of decline over the last three decades and, for the first time, to record some regeneration, with the presence of new, young trees. To cite this article: F.

The radial growth of Duprez' cypress (Cupressus dupreziana A. Camus), a tree endemic to the Tassili n'Ajjer in the Central Sahara, was measured from cores taken in 1967 and 1997 from the same trees. A comparison of these cores, spanning 30 years, reveals that even in this hyper-arid climate, this species has a juvenile vigour comparable to other Mediterranean Cupressaceae. Wide individual variability was found, however, which was induced by the strong influence of microhabitat factors. Traditional dendrochronological methods of cross-dating are impossible to apply in the case of these trees. Ages of eight individuals were estimated with the help of radiocarbon dating, yielding an age range from 600 to 2400 years for trees of the most usual girths. This work is dedicated to the memory of Françoise Serre.F. Abdoun ( ) UMR EcoBio 6553, Université Rennes-1,

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In North Africa, Cedrus atlantica forests are in decline, following decades of anthropogenic pressure and repeated drought events. Mixed C. atlantica-Quercus ilex stands located in the Theniet El Had National Park (northwestern Algeria) were considered in the present study. Based on a stratified sampling, six temporary plots were established to describe structure (species composition, density, total height, diameter and basal area) and radial growth in relation to type of stand (pure and mixed), using a dendroecological approach. The diameter distribution of C. atlantica indicated the presence of few young individuals and a poor regeneration status in all the stands. The density and basal area of C. atlantica were significantly higher in pure stands, which necessitate silvicultural operations. In contrast, Q. ilex showed a progressive dynamic, at moderate altitude. Radial growth showed a significant decline from 1980 to the 2000s. The absence of an appropriate management plan and the increase in anthropogenic effects, without ruling out a role for the current climate conditions marked by drought, seem to be the causes of C. atlantica decline.

Effet des facteurs stationnels sur la croissance radiale et la réponse du pin d'Alep au climat dans le massif de l'Ouarsenis, Algérie Photo 1. Vue d'ensemble de la zone culminante de l'Ouarsenis où de vastes pinèdes se développent sur substrat calcaire. Photo M. Sarmoum. Correspondance électronique avec les auteurs / Electronic correspondence with authorssarmoum_med@yahoo.fr B O I S E T F O R Ê T S D E S T R O P I Q U E S , 2 0 1 6 , N° 3 2 9 ( 3 ) ABSTRACT EFFECTS OF STATION-SPECIFIC FACTORS ON RADIAL GROWTH AND RESPONSES TO CLIMATE IN ALEPPO PINES IN ALGERIA'S OUARSENIS RANGEThe relationships between climate and radial growth from 1967 to 2010 in nine Aleppo pine stands in the Ouarsenis range (north-western Algeria) were studied according to station-specific factors (substrate, altitude, exposure and age of the trees) using dendro-chronological methods, with an analysis of interannual variations in the thickness of growth rings. A retrospective analysis of radial growth showed high interannual variability in growth ring thickness within the same stand. The statistical parameters calculated showed highly variable radial growth between the different stands, which was related to station-specific factors and to tree age. Average growth ring thickness and persistence declined with the age of the trees. Average sensitivity to climate tended to be greater in trees growing on sandstone or schist substrates than on limestone. Our analysis of the relationships between climate and growth rings shows that the Aleppo pine is responsive to precipitation before or during the formation of growth rings. Higher temperatures, especially when they reach their maximum, have a negative effect on radial growth. The relationships between Aleppo pines and climatic conditions are modulated by station-specific factors, especially the substrate. The most responsive stands tend to be growing on a sandstone substrate. These results provide a useful description to help understand the ecological flexibility of the Aleppo pine and how it responds to climate change, with a view to proposing better ways of protecting pine forests that have been under threat for several decades.Keywords: Pinus halepensis, station-specific factors, radial growth, relationships between growth rings and climate, drought, Ouarsenis. RESUMEN EFECTO DE LOS FACTORES DE SITIO EN EL CRECIMIENTO RADIAL Y RESPUESTA DEL PINO CARRASCO AL CLIMA EN EL MACIZO DE OUARSENIS, ARGELIASe estudiaron las relaciones entre clima y crecimiento radial de nueve poblaciones de pino carrasco en el macizo montañoso de Ouarsenis (Noroeste de Argelia), en el período 1967-2010, atendiendo a factores de sitio (sustrato, altitud, exposición y edad de los árboles) y aplicando métodos de dendrocronología. Se analizaron las variaciones interanuales del ancho de los anillos. El estudio retrospectivo del crecimiento radial indica una alta variabilidad interanual del ancho de los anillos entre individuos de una misma población. Los parámetros estadísti-cos calculados reflejan indican una alta variabili...