Germination of Pinus pinaster, P. radiata and Eucalyptus globulus in relation to the amount of ash produced in forest fires

Abstract

-Many studies have found that ash beds favour seedling growth, but the effect of ash on the germinative behaviour of tree species has received little attention. We therefore designed an experiment in which Pinus pinaster, P. radiata and Eucalyptus globulus seeds underwent four different ash treatments and one control. The treatments chosen were three solutions of ash in water (0.5, 1 and 5 g L -1 ) which were used to periodically water the seeds of each species, and a treatment in which a certain amount of ash was applied directly to seeds which were moistened with distilled water only. Six replicates of 30 seeds per replicate from each species were used for each treatment. Seeds were incubated on a double layer of filter paper in Petri dishes under laboratory conditions. Germination counts were taken every 2 days until the end of the germination period. The results indicated that ash (in the quantities and under the conditions studied) had no postive effect on the germination of these species. The ash solutions did not significantly alter the germination rate with respect to the control. Only the germination percentages obtained in the ash treatment markedly reduced the germinative capacity of P. pinaster and P. radiata and had a completely inhibitory effect in the case of E. globulus.

The influence of seed age on germinative response to the effects of fire in Pinus pinaster, Pinus radiata and Eucalyptus globulus

“…Their effect on germination was either null or inhibitory. Similar results were obtained by [8,15,16,26,28,31,32,35,36,37,44], in different species of pines and eucalyptus.…”

“…These four treatments were applied to all of the groups of seeds collected in the 4 years mentioned. All of the treatments consisted of six replicates of 30 seeds each, using the methodology of previous studies [36,37,38].…”

“…The temperature and time periods selected, as well as the ash treatment used in this experiment are similar to those used in other studies that examine the effect of forest fires on the germination of different species [21,22,28,31,35,37,38,41,43,44,45].…”

Seed germination ofQuercus robur, q. pyrenaicaandq. ilexand the effects of smoke, heat, ash and charcoal

“…The Ash treatment was performed by adding 0.168 g of ash to each of the incubation trays. This amount of ash was selected after taking into account the surface area of the trays and that Soto et al [41] registered 8 g of ash/m 2 in a real wildfire, as well as other studies on the effect of ash carried out by the authors [36,38]. The Charcoal treatment was performed by incubating the seeds of each tray in the presence of 1 g of fragmented charcoal.…”

“…There are many studies that analyse the effect of heat on the germination of different arboreal [20,39,40], 206 O. Reyes, M. Casal shrub [15,18,45,46,53] and herbaceous species [11,15,18,20,22]. There are some studies that analyse the effect of ash, charcoal or smoke [4,5,15,23,29,36] and there is a vast ignorance of the germinative behaviour after fire of Quercus.…”