Seeds of ten species of Cistaceae, Ericaceae and Poaceae were examinated to compare their responses to high temperatures and ash, simulating the direct effect of fire on germination. A variable response to these factors between families and within species from the same family was detected.In Cistaceae, heat treatment pre-sowing stimulated germination. In Ericaceae, germination was stimulated by thermic shock, but a wide range of response was detected (between all four species), from Erica ciliaris, very sensitive, to Daboecia cantabrica and Calluna vulgaris which showed no significant response. The range of reaction shown by the species of this family suggest that the size of the seeds is directly related to the difference in response, at least in species with a similar structure. In Poaceae, germination was not found to be dependent upon thermic shock.The effect of ash varies in magnitude. Although it decreased the germination percentage in all species, in Avenula marginata (Poaceae) the effect was not statistically significant, whilst in Ericaceae, particularly in those showing the highest levels of germination in the control (C. vulgaris and E. umbellata), the effect is to inhibit germination completely. In respect to the effect of ash the families could be arranged in the order Ericaceae> Cistaceae>Poaceae.Complex interactions between various dormancy types and seed size could explain these results. In species which depend on physical dormancy temperature has an important role. When other dormancy type is dominant in the control of germination, the medium characteristics could have a relevant role on seed response. In addition, the seed-size could determine the threshold of tolerance to temperature.Nomenclature Tutin et al. (1985).

The effect of high temperatures and smoke on germination was tested on the shrubland Leguminosae species, Adenocarpus lainzii, Cytisus scoparius, Cytisus striatus, Genista berberidea, Genista triacanthos, and Pterospartum tridentatum, which are abundant and widely distributed throughout the north-western Iberian Peninsula. Light thermal shocks (80°C, 5 min and 80°C, 10 min) and medium thermal shocks (110°C, 5 min and 110°C, 10 min) stimulated seed germination in C. striatus, A. lainzii, and P. tridentatum. The treatments 80°C, 10 min and 110°C, 5 min stimulated germination in C. scoparius but only 110°C, 5 min did so in G. berberidea and G. triacanthos. The intense thermal shocks (150°C, 5 min and 150°C, 10 min) inhibited germination in all of the species studied but the inhibition effect was already detectable at 110°C, 10 min in G. berberidea. From the results, it was impossible to relate the different levels of smoke used to the variations in the germination response of the species studied. The increase in the germination level after fire was more important in C. scoparius, C. striatus, A. lainzii, and G. triacanthos, which are non-resprouters.

-Pinus genus is characterized by woody cones able to open even after a forest fire, which also protect seeds from damages during the fire. The aim of the present study is to analyze the effect of high temperatures on pine cones opening as well as the releasing and viability of the seeds of P. pinaster and P. radiata, throughout a selection of different combinations of temperatures and time exposures. During a forest fire, extremely high temperatures have a very low remanence. 26 different combinations were selected, beginning by 500 ºC/1 min and then gradually increasing time exposure whereas the temperature, on the opposite, was set lower and lower. This process was applied up to combinations of relatively low temperatures and long lapses of time such as 100 o C/30 min. 5 cones from each species were tested with each combination, a total of 260 cones were finally set under study. P. pinaster species showed a scales' opening of 50% on average whereas P. radiata neared 90%. The rate for P. radiata seeds' releasing is also higher than P. pinaster's. Finally, the viability of the seeds remained unchanged under the influence of thermal shocks for both Pinus species. fire / high temperatures / pine cone opening / P. pinaster / P. radiata Résumé -Effet des hautes températures sur l'ouverture des cônes, la dissémination et la viabilité des semences de P. pinaster et P. radiata du NO d'Espagne. Le genre Pinus présente des cônes ligneux qui protègent les semences du feu et qui s'ouvrent même après le feu. Le but de cette étude est de connaître l'effet des hautes températures sur l'ouverture des cônes, ainsi que sur la dissémination et la viabilité des semences des espèces P. pinaster et de P. radiata au travers des différentes combinaisons de températures et temps d'exposition. Lors d'un feu de forêt les très hautes températures ont un temps de remanence très peu élevé ; on a fait une sélection de 26 diffé-rentes combinaisons de températures et temps d'exposition, à partir de 500 ºC/1 min et en augmentant progressivement le temps d'exposition. L'on a fait décroître la température, jusqu'à des combinaisons de températures relativement basses avec de longs laps de temps (100 ºC/30 min). Chacune de ces combinaisons de facteurs a été appliquée à 5 cônes de chaque espèce, un total de 260 cônes a été étudié. L'espèce P. pinaster a présenté un taux moyen d'ouverture d'environ 50 % de ses écailles, alors que le P. radiata s'approche de 90 %. Le taux de semences disséminées est aussi plus élevé pour P. radiata que pour P. pinaster. Finalement, la viabilité des graines n'a pas changé sous l'influence des chocs thermiques et ce, dans aucune des deux espèces de Pinus. feu / hautes températures / ouverture des cônes / P. pinaster / P. radiata Ann. For. Sci. 59 (2002) 327-334 327

Summary — The action of fire was simulated in the laboratory using thermic shocks. To this aim, samples of seeds of Pinus pinaster, P radiata and P sylvestris were subjected to high temperatures. Following the treatments, both the treated and untreated seeds were sown under standard laboratory conditions. The results of the germination test demonstrated that significant differences exist between the behaviour of the 3 species, but none of them were seen to be specially favoured by the high temperatures.

Question: Is it possible to model the germinative and resprouting behaviour of plant species in Atlantic shrublands and woodlands in relation to fire intensity? Is it possible to recognise different functional regenerative types in these plant species? Location: Galicia, NW Iberian Peninsula. Methods: We explored the patterns of germination and resprouting plant responses in relation to different intensities of fire using data from 37 trees, shrubs and herbaceous species growing in Atlantic shrublands and woodlands. Results: Synthesizing their germinative and resprouting behaviour, we created two graphical models: the Functional Germinative Model (FGM) and the Functional Sprouting Model (FSM). Integrating the germinative and resprouting responses, and taking into account fire intensity, we created the Functional Regenerative Model (FRM), which predicts the post‐fire recuperation of the populations of each species. The FRM has been validated with data from four Atlantic communities. We identified four plant functional regenerative types (PFRT) for Atlantic forest vegetation and we propose three intensities of response. Conclusions: The extracted models (FGM, FSM and FRM) and the grouping of species in four PFRTs could be applicable to more Atlantic species, to disturbance ecology in general and to population, community and landscape management.