As a consequence of the megadrought in Central Chile, it is expected that most of the distribution of woody species will be narrowed in the northern limits because of restrictions imposed by soil matric potential on seed germination. In this study, we analyzed the effect of the soil matric potential on seed germination and initial recruitment of the sclerophyllous species Prosopis chilensis, Quillaja saponaria and Cryptocarya alba from contrasting geographic origins (i.e., seed sources). We evaluated the germination capacity (%) under different matric potentials (i.e., 0, −6, −33, −750 and −1250 kPa) for 100 days. Soil matric potential of −1250 kPa negatively affected the germination capacity of the three species. P. chilensis seeds stopped germinating under soil matric potential close to −1200 kPa, whereas in Q. saponaria and C. alba the complete inhibition of germination was under −1000 kPa. Seed sources also differed in their germination capacity by soil matric potential: northern seed sources of P. chilensis germinated with the lowest soil matric potential. There was no clear trend in Q. saponaria and C. alba, but in general, southern seed sources performed better than the northern ones. The results showed that Ѱm in the soil played an important role in the germinative capacity against different seed source origins, but not in soils with a north–south gradient.

Natural regeneration of recalcitrant-seeded tree species is strongly limited in Mediterranean-type climate zones due to increasing droughts imposed by climate change. Direct seeding can be a low-cost alternative to seedling establishment, but there is still limited information for some species. This study aimed to assess the effects of the seed source and forest cover on the germination and survival of the endemic Cryptocarya alba Mol. established through direct seeding. Three habitat types differing in forest cover were identified within the natural park Reserva Natural Altos de Cantillana, Metropolitan Region, Chile. The forest cover corresponded to open (canopy density <25%), semi-dense (canopy density around 50%), and dense forest (canopy density >75%). All forest cover had C. alba as one of the dominant species. At each habitat type, 38 families from four seed sources (Cuesta La Dormida (CD), Antumapu (AN), Cantillana (CA, local seed source) and Cayumanque (CY)) were directly seeded. Germination (Germin) and survival (Surv) were evaluated weekly during one growing season. There were significant differences between seed sources in Germin and Surv, with means values varying from 7.8% to 37% for Germin and 0% to 20% for Surv. The local seed source CA had the highest values in both traits. A significant variation was also observed between families within seed sources only for Germin. The dense forest cover had the highest Germin (22%) and Surv (55%) results compared to the other forest cover types, which was partially associated with differences in soil moisture, temperature, and bulk density. Due to the most frequent droughts in these Mediterranean-type climate zones, the use of local seeds on dense forest cover is recommended for the direct seeding of the species in the initial recruitment.

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Climate change is threatening the restoration efforts in Mediterranean ecosystems, and there is still little knowledge about the responses of some sclerophyllous species to plant management techniques. This study assessed the effects of the planting date, use of mulch, and controlling light levels on the early survival and growth of sclerophyllous species established in island plots. A factorial design was installed in the Metropolitan Region of central Chile, with a treatment combination that included three planting dates (January: midsummer, April: autumn, and June: winter), three light levels (full sun exposed (T0), shaded at 35% (T35), and shaded at 70% (T70)), and two mulch levels (no mulch versus mulch application). Additionally, we tested the species effects within the island plot. We measured survival, as well as plant diameter and height increments, 1 year after establishment. Each island plot contained three seedlings of Acacia caven Mol., two of Quillaja saponaria Mol., two of Maytenus boaria Mol., one of Schinus polygamus (Cav.) Cabrera, and one of Cryptocarya alba (Mol.) Losser. We found a significant main effect for all the factors assessed. Despite the high mortality in the trial, survival was increased around fourfold by planting in winter, using mulch, or using either of the shading levels. At the species level, average survival ranged from 7% for C. alba to 27% for S. polygamous. To increase plant survival in the restoration of this ecosystem, it is necessary to intensify the management techniques and the use of these types of eco-technologies; if not, the restoration may fail.