Comparison between Anderson nuclei and mixed planting: how spacing influences growth performance and functional groups of native species in the restoration of Araucaria forests in southern Brazil

Abstract

Active restoration strategies are crucial for accelerating forest recovery in highly degraded landscapes within the Araucaria Forest. This study evaluated the effects of two different spatial arrangements: Anderson nuclei and mixed planting on the dendrometric performance of three representative native species (Mimosa scabrella, Araucaria angustifolia, and Solanum diploconos). Data were collected 45 and 57 months after planting and analyzed using multivariate tests (MANOVA) and univariate comparisons. The results showed significant effects of treatments, species, and their interactions on height, diameter at ground level, and canopy projection. Mimosa scabrella, a fast-growing pioneer species, maintained structural dominance across all treatments and years. Araucaria angustifolia, a mid- to late-succession species, showed modest growth in 2023 but responded significantly in 2024, particularly in the Anderson nuclei. Solanum diploconos showed consistently lower values, but with gradual increases, compatible with its shade-tolerant understory niche. Comparisons between the arrangements indicated that the Anderson cores promoted more pronounced facilitation effects, favoring the growth performance of mid- and late- successional species and accelerating canopy closure. At the same time, mixed planting resulted in more homogeneous but less expressive growth patterns. The Anderson’s core technique is an ecologically sound alternative to mixed plantings, as it combines the rapid growth of pioneer species with the creation of a facilitative environment, accelerating the succession process and helping achieve restoration objectives more efficiently