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Issue 21, 2026

Online ISSN: 2466-4367

, Issue 21, (2026)

Published: 22.01.2026.

Open Access

This Special Issue of Reforesta, International Practices for Regenerating and Restoring Forest Trees by Seeding, brings together regional practice and research from North America, South America, Europe, Asia, and Oceania on using broadcast and direct seeding to create forest cover. It presents a significant range of seeding activities inclusive of species, forests, sites, and climates. Seeding has regained interest because of its scalability and cost-effectiveness, particularly for remote or inaccessible areas, sites with low productivity where planting seedling costs are prohibitive, or when aiming for a more natural forest structure. Technological innovations, particularly in seed treatments, automation, and precision seeding improve success of large-scale seed dispersal.

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01.12.2020.

Review paper

Irrigation in pine nurseries

This review provides information and opinions about irrigation practices in pine nurseries. Even when nurseries receive more than 15 mm of rainfall week-1, managers irrigate seedbeds to increase germination, increase seed efficiency, and increase root growth. In the southern United States, a 7-month old pine seedling in an outdoor nursery typically receives 2 to 6 kg of water supplied from either sprinklers (39 nurseries) or center-pivot irrigation (12 nurseries). Most nursery managers do not intentionally subject the crop to moisture stress, since most reforestation sites receive adequate rainfall, and many studies show that reducing root mass does not increase seedling performance. In fact, nursery profits can be reduced by more than $13,000 ha-1 when deficit irrigation reduces average seedling diameter by 1 mm. Although some researchers believe that failure to properly drought stress pine seedlings might increase outplanting mortality by up to 75%, research over the past 40 years does not support that myth. When pine seedlings average 5 mm (at the root-collar), water stress is not a reliable method of increasing tolerance to an October freeze event. In several greenhouse trials, researchers grew and tested seedlings that nursery managers would classify as culls (i.e., dry root mass < 0.5 g). Unfortunately, it is common for researchers to make irrigation recommendations without first developing a water-production function curve.

David B. South, Ryan Nadel