Extensive disturbance to the ecologically, socially, and economically important pine (Pinus spp. L.) forests of the Mediterranean region has created a strong need for forest restoration throughout the region. Seeding could potentially be a viable option for regenerating some of the 10 pine species that occur in the region, especially the fire-adapted serotinous species, but previous seeding efforts have been marked with inconsistent success. From our synthesis of available literature and practical experience, we briefly summarize the history of applied trials and pine seeding research, examine the factors that determine pine seeding success, and discuss what we have learned that can make seeding an ecologically and economically viable approach to pine forest establishment in the Mediterranean region. Future refinement of autonomous drones for seed delivery, selection of favorable sowing microsites, and improvement of seed coating technologies that minimize seed predation and support seedling establishment will support “precision restoration” practices that promise to advance pine seeding to an operational scale in the Mediterranean region.

Sweden is known for its coniferous forests, but two oak species occur in the south, Quercus robur and Q. petraea, in pure stands or mixed with other species. Oak forests have declined due to land use changes, industrial forestry favoring conifers, and browsing by wild ungulates. Oak grows best on deep, fertile soils but can survive on a range of sites, supporting high biodiversity, and have cultural, aesthetic, and recreational value. The temperate climate is expected to change, and the increased temperature and rainfall potentially will favor oak over other species. Historically, high sowing rates and low-cost labor contributed to successful oak establishment; planting has since become the main method. Interest in seeding is returning, but predation and germination risks make it less certain than planting. Site preparation and high seeding density can help mitigate losses where heavy acorn predation by rodents is expected. Competition from other vegetation requires intensive mechanical site preparation and periodic cleaning operations. Seeding is more successful on abandoned farmland with less rodent habitat and where agricultural practices can be used for site preparation and maintenance. Expensive fencing is required for protection from browsing, especially in the first 10 years. Restoration success requires regular assessment and management, with lower oak seedling densities acceptable if other species are present. Lack of experience among managers is a barrier; more information and communication about successful practices are needed.

Brazil contains 15–20% of the world’s biodiversity, with forests originally covering 88% of its territory, now reduced to about 58%. The country has committed to restoring at least 12 million ha of forests by 2030. Seeding is a cost-effective method for tropical forest restoration, widely used in Brazil, but its effectiveness for species-rich forests is still uncertain due to low establishment rates for many species. Most seeding research has involved relatively few species, and many are short-lived, raising concerns about long-term ecosystem development. Invasive grasses and loss of native species are major barriers to restoration. There is a significant gap between seed demand for restoration and current production capacity. Seed dormancy can be a barrier to rapid establishment; treatments to break dormancy must be tailored to species and site conditions. Large-seeded species and those with certain functional traits (e.g., deep roots, storage cotyledons) perform best. The main sowing methods are broadcast, line, and seeding holes, each suited to different site conditions. Muvuca is a notable technique involving a diverse seed mix for large-scale restoration. High sowing rates are often necessary due to low emergence and establishment rates. Fencing and ant control (especially leaf-cutter ants (Atta spp. and Acromyrmex spp.)) are critical to protect seeds and seedlings from herbivory and physical damage. Ongoing weed control is essential for successful establishment. Seed availability, low establishment rates, and competition with invasive species are the major limiting factors.

The rapid decline of whitebark pine (Pinus albicaulis Engelm.), a keystone species of upper subalpine and treeline elevational zones across many of the higher mountains of the western United States and Canada, has prompted the development of restoration strategies and practical restoration applications. Whitebark pine has been federally listed as ‘threatened’ in the United States, which elevates the restoration imperative. Seeding potentially provides a low-cost means of establishing the species in remote areas with limited access and/or land use constraints, but this restoration tool still lacks sufficient advancement to ensure operational success. We present an overview of whitebark pine ecology, outline the factors leading to its decline, summarize ongoing conservation efforts and restoration strategies, and review the available literature on seeding whitebark pine to identify barriers that challenge successful operationalization. Informing and advancing land management for conservation of whitebark pine will require refining seeding protocols by monitoring and reporting on trials to mitigate the main barriers to this application. Additional research is required to reduce seed pilferage by rodents, improve sowing techniques, identify favorable sowing microsites for improved seeding outcomes, and develop a reliable supply chain for seed resistant to introduced disease.

New Zealand supports rich temperate forests believed to have occupied up to 80% of its land area below climatic tree line prior to human arrival in the 11th century, but deforestation, particularly motivated by conversion to agricultural systems in the last 150 years, has decreased today’s forest cover to less than 30% of the original estimate. There is currently interest in relatively large-scale afforestation of degraded lands, and this has initiated research and development to improve seeding of native forest species. We provide a synthesis of available literature, ongoing research, and practical experience to identify critical aspects of candidate afforestation sites, summarize practices and techniques used in current seeding research and operations, and recognize factors that affect success or failure of seeding native species. The main challenges are that pastoral farming has dramatically altered the soil microbiome, non-native mammalian herbivores and weeds reduce seedling establishment success, and many native trees are mast seeding or have recalcitrant seeds. Selection of sites with predictably adequate rainfall, deployment of fast germinating pioneer species, procurement of high-quality seed, availability of appropriate soil symbionts, and post-establishment weed and animal control are all important components of success when seeding native forest species in New Zealand.

Seeding is gaining popularity in global forestation for its scalability and cost-effectiveness, especially where nursery stock is limited. It enables rapid, large-scale forest establishment, even on remote or degraded sites, and allows control over species and genetic diversity. Seeding is cost-effective for inaccessible or low-productivity areas and is used in ecological restoration to boost biodiversity. Success depends on species, seed quality, timing, soil, and site management. It is best suited for areas where natural regeneration is infeasible, low-cost forestation is needed, sites are remote or difficult to access, or rapid resource control is required. Germination and establishment rates are generally low (average germination ~44%, establishment ~21%), with significant variability by species and site. Large-seeded, fast-germinating species perform better. Seed availability and quality are key challenges. Proper timing, storage, and site preparation are crucial, particularly for species with recalcitrant seeds. Methods include broadcast and direct placement, with drone seeding emerging for large projects. Higher seeding rates are needed for small seeds and broadcast methods. Climate change is increasing drought and heat stress, making moisture retention and microclimate management more important. Technological advances, like automation, seed treatments (coatings, biochar, mycorrhizal inoculation and encapsulation), and precision seeding, are improving outcomes. Combining seeding with planting can enhance diversity and success, but careful planning and ongoing management remain essential.

Previous afforestation effort, much of which was accomplished with aerial seeding, restored Pinus massoniana Lamb. forests across more than 4 million ha of barren lands and difficult mountainous terrain in Ganzhou, Jiangxi Province, China. This manuscript provides a review of literature reporting the factors that led to forest and site degradation, conventional practices and techniques used to widely establish forest cover of P. massoniana, and post-sowing and plantation management practices used to encourage development and growth of restored P. massoniana forests. Factors known to impede successful seeding of P. massoniana include poor seed quality, harsh soil and site conditions such as soil erosion and droughty soil, unpredictable and extreme weather or climatic events including drought, frost, or excessive rainfall, and insufficient site preparation or plantation maintenance. Procuring high-quality seed, conducting thorough site assessments, and implementing practices that effectively mitigate factors that limit seed germination, seedling establishment, and tree growth are key to successful P. massoniana seeding.

Broadleaf species dominate Serbia’s diverse forests including the Srem Forest District, where oak regeneration is focused on the Ravni Srem portion of the district. Pedunculate oak (Quercus robur L.) is the dominant species, making up about 50% of standing volume. The most important supporting species in mixed stands are narrow-leaved ash (Fraxinus angustifolia Vahl) and common hornbeam (Carpinus betulus L.). Seeding is used when acorn crops are poor or absent. In good mast years, acorns are incorporated into the soil or sown mechanically (about 450 kg ha-1), 2 to 5 cm deep in rows 0.7 m apart with acorns spaced 15 to 20 cm in a row. Seeds are manually collected from registered stands and orchards, and subject to quality testing, thermotherapy, and fungicide treatment before storage. Herbicides and arboricides are used to control competition. Fencing protects seeds and seedlings from animals; rodenticides, fungicides, and insecticides are applied as required. Regeneration areas are limited to 56.25 ha, with seed trees left for shelter. Sowing is done in autumn–winter using machines, with acorns spaced in rows. Early competition is controlled by herbicides. Mechanical weeding and fencing continue during the sapling phase. Fire lanes are established and maintained for up to 15 years. Success is measured by seedling establishment and survival after the first growing season. Impacts of invasive plants and animal damage are mitigated by site management and maintaining fencing. Failure is mainly due to unfavorable climatic factors. The moderate-continental climate is expected to experience increased temperature and precipitation by 2040.

This manuscript introduces the current special journal issue International Practices for Regenerating and Restoring Forest Trees by Seeding, for which the concept and effort to undertake were motivated within the IUFRO Task Force on Transforming Forest Landscapes for Future Climates and Human Well-Being. The journal issue, comprised of contributions from North America, South America, Europe, Asia, and Oceania, represents a significant range of seeding activities inclusive of scores of species, forests, forestation sites, and climates. Approached as an information guide and source of advancements that are being studied and applied in contemporary practice around much of the globe, International Practices for Regenerating and Restoring Forest Trees by Seeding provides a synthesis of regional practice and research intended for an audience of early career scientists, practitioners, and policy makers working in forest restoration.

Tropical montane cloud forests in Mexico, though rich in unique species, cover less than 1% of the country and face severe deforestation and ongoing threats, especially to oaks (Quercus spp.). Our study in the montane cloud forests in the Jamapa and La Antigua River basins of central Veracruz tested acorn seeding for forest restoration. Field trials were conducted across peri-urban and rural secondary forests, employing a range of acorn protection devices (e.g., wire mesh cages, chili pepper (Capsicum spp.) covering) and site preparation techniques to mitigate predation by rodents (Order Rodentia) and other fauna. The study also assessed the influence of microsite selection and pre-germination treatments on seedling emergence. Various rodents were the main obstacle to seeding success, exclusion devices like wire mesh cages greatly improved outcomes. Effectiveness depended on species, site, and year. Chili pepper coverings did not deter birds, and they exposed the acorns to seed predators. Successful restoration requires careful microsite selection; acorns are less preyed upon by rodents in areas with low to moderate vegetative cover. Seeds should be collected from multiple mother trees during peak fall and inspected for viability. When storage is needed, acorns should be stored under controlled conditions to maintain moisture and prevent fungal contamination. Acorn masting leads to variable seed availability modulating seed predation patterns; mast years are optimal for seeding projects. These findings underscore the need for adaptive, site-specific restoration protocols, including rapid pilot trials and monitoring of acorn production cycles.