The effects of deadwood on tree regeneration and microsites: A systematic review

Large-scale disturbances like fire, bark beetle outbreaks, and windstorms increasingly affect forest ecosystems . Rather than salvage logging, retaining deadwood may support tree species regeneration. This systematic review summarizes the role of deadwood in creating microsites to facilitate tree regeneration. We conducted an English-language literature search in the Web of Science and Scopus. After the title-abstract screening, we classified studies that met our eligibility criteria into three subtopics: deadwood as (1) substrate, (2) browsing protection, and (3) microclimate improvement. We then performed a snowball sampling using the literature search tool ResarchRabbit. The final qualitative synthesis included 161 studies (browsing: n = 34, microsite: n = 64, substrate: n = 68; five studies occurred in two subtopics). Our review revealed the importance of coarse woody debris (CWD) as a regeneration substrate, particularly for small-seeded conifers, which preferred CWD over the forest floor. Establishment success depended on the decomposition stage, CWD species, stem diameter, and moss cover. Deadwood reduced browsing pressure, where fallen trees formed barriers limiting ungulate browsing access and individual logs or branch piles protected seedlings. Logs enhanced tree species regeneration on open sites by improving seedling survival and growth, especially on the north and nearby sides. Deadwood, including logs, snags, and logging slash, significantly influenced the microclimate by moderating soil temperatures. The effects on soil moisture were variable. In conclusion, deadwood retention has the potential to serve as a modular toolbox in post-disturbance forest management. • Review of 161 studies on deadwood in boreal, Mediterranean, and temperate forests. • Post-disturbance deadwood retention creates safe sites for tree regeneration. • Tree regeneration is facilitated by substrate, shelter, and microclimate effects.