Seedling survival in reforestation: how nurses and seedling traits shape restoration of burned Araucaria forests
Vera L. Emprin, Sofia Cingolani, Javier Sanguinetti, Karina L. SpezialeAbstract
Introduction
Reforestation is crucial for restoring severely burned forests, and monitoring seedling performance is essential for improving it. Conifer seedlings are particularly vulnerable to summer drought. Plant size can influence water uptake and drought tolerance, while facilitation by nurses can reduce seedling desiccation by buffering microsite conditions. Restoration of burned Pehuen ( Araucaria araucana ) forests provides a valuable model for assessing how plant size and nurse facilitation influence reforestation success.
Objective
Evaluating early Pehuen seedling performance in relation to seedling size and the presence and characteristics of potential nurses to identify best reforestation practices.
Methods
We measured planted seedling size, nurse presence in planting microsites, and nurse characteristics (cover, distance, orientation, and identity), and evaluated seedling survival and desiccation one year after planting in three plantations.
Results
Seedling survival (26.5–83.5%) and dry tissue (37.2–83.4%) varied widely among planting events. Smaller seedlings showed higher survival (70.3%) than medium ones (48.8%), and average survival was 21.9% higher with nurses. Nurses also reduced desiccation, decreasing dry tissue by 6.9–20.2 points across sizes. Nurse characteristics affected their effectiveness, with lowest dry tissue under nearby, northwest‐oriented, high‐cover trees. Planting small seedlings in microsites with effective nurses increased survival by up to 41% and reduced dry tissue by up to 63%.
Conclusions
Higher performance of smaller seedlings likely reflects a favorable shoot‐to‐root balance enhancing drought tolerance. Nurses improve microsite conditions by buffering solar radiation and wind, with live vegetation providing greater facilitation.