International Scientific Journal on Reforestation, Afforestation and Tree Reproduction
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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.

Research paper

Two studies of the potential of drought preconditioning to enhance deep root production in seedlings of western larch (Larix occidentalis)
Climate change is increasing the frequency and intensity of drought in the western USA. Evidence suggests that drought preconditioning of plants may improve the survival of planted seedlings under dry conditions through enhanced water uptake by roots, but the mechanisms underlying enhanced survival under drought remain unknown. We tested whether the vertical distribution of roots in root plug cross-sections varied with drought preconditioning and seed source. We subjected western larch (Larix occidentalis Nutt.) seedlings from eight different provenances to Low (50-65% gravimetric water content), Moderate (65-75%), and High (≥75%) watering regimes in a nursery. We then investigated dry root mass across four root-plug sections, including the taproot and three lateral root cross-sections (top 1/3rd, middle 1/3rd, and bottom 1/3rd of root plugs). We also tested for carry-over effect of drought preconditioning on the mass of egressed roots observed among cross-sections of potting soil in a 30-day potted study. Root plug mass varied significantly (P< 0.001) with watering regime, root plug cross-section, and an interaction between watering regime and cross-section. Overall, seedlings that received less water produced lateral root plug cross-sections of greater mass, which coincided with taproots of less mass. In contrast to findings from the root plug study, the distribution of egressed root mass among cross-sections of potting soil did not vary with drought preconditioning. This is the first study to assess seedling root growth in response to drought preconditioning in western larch with a focus on the distribution of root mass in root plugs and egressed root mass among soil cross-sections. We expect this work to facilitate future efforts to improve drought hardiness of western larch seedlings. Future improvement of western larch seedlings will require investigation into whether altered root plug mass distribution translates to improved seedling performance in outplanting trials.

Ashleigh Vale, Ehren Moler, Andrew Nelson