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Deforestation and forest degradation continue at alarming rates. Landowners often clear forest patches for alternative use, creating landscape mosaics of different land‐use legacies. Ecological restoration is usually monitored by aboveground processes, while belowground processes are far less studied. We addressed how the abundance and activity of nutrient improvement bacteria contribute to restoration success, considering different restoration interventions and land‐use legacies. We assessed the abundance and potential activity of N‐fixing and P‐mineralizing bacteria in the rhizosphere of 279 two‐year‐old Quercus mexicana plantlets in a disturbed oak forest in central Mexico. We analyzed the differences across landscape patches (eroded landslide, pastureland, and forest) of four common restoration interventions: passive restoration, artificial shading, topsoil translocation, and combining both treatments. Restoration interventions modified soil functioning differently across landscape patches with a significant increase of P‐mineralizing bacteria abundance and potential activity in the landslide and pastureland. In contrast, N‐fixing bacteria increased only in the landslide site where we registered the lowest organic matter content. Surprisingly, interventions that enhance bacterial activity and abundance do not necessarily improve short‐term seedling performance. We recommend considering the landscape heterogeneity to better match the restoration interventions with the prevailing degradation factor in each landscape patch. Also, combining restoration strategies does not necessarily result in synergy and may imply a useless expense of resources. Finally, monitoring soil health provides novel insights to understand restoration trajectories that remain undetected when focusing only on seedling performance. [ABSTRACT FROM AUTHOR]

The natural regeneration of forests is declining in human‐modified landscapes and overcoming ecological barriers to the seedling establishment is paramount to its restoration. This study focus on two common forest regeneration barriers: excessive sun exposure and low‐quality soils. A degraded clearing with eroded and compacted soils within a disturbed oak forest in Mexico was chosen, and 20 experimental plots in a randomized factorial block design were set up to test seedling performance in the artificial shade and in forest topsoil that was transferred from a nearby remnant forest, as well as a combination of both. We sowed 400 acorns from two oak species (Quercus eduardii and Q. viminea) and monitored the emerging seedlings for 63 months. Our results confirm different survival and growth rates between species, ontogenetic stages, and environmental micro‐conditions. The effect of artificial shade on seedling performance was positive in weathered soil but negative or neutral in transferred forest soil. Restoration interventions did not have additive benefits; seedling performance was improved by both restoration interventions applied separately though was not further enhanced when both actions were combined. Both species had different mechanisms to cope with water stress, which resulted in different photosynthetic rates under full sun. Trade‐offs resulted in different life stages that were more enhanced by different restoration strategies; survival and growth were most enhanced by applying artificial shade or transferring forest topsoil, respectively. Restoration practitioners may prioritize seedling survival in harsh conditions and growth in less severe degraded sites or apply interventions sequentially over time. [ABSTRACT FROM AUTHOR]

One of today's environmental challenges is reducing greenhouse gases (GHG) through reforestation. Forest plantations with adequate species composition and management sequester carbon and restore degraded areas simultaneously, but methods to estimate their biomass must be refined. In Mexico's Lacandon Jungle, 103 trees were harvested to determine allometric equations for four abundant Neotropical species with high potential for restoration: Guazuma ulmifolia, Trichospermum mexicanuum, Inga vera and Ochroma pyramidale. The best biomass predictors were diameter at breast height and at the base, which generated allometric relations with r² 0.90 or higher. Based on these relations, average biomass accumulation in two-year-old monocultures of Inga, Ochroma, Trichospermum and Guazuma were calculated at 6.60, 30.80, 47.62 and 48.12 Mg ha-1. Restoration plantations with the last two species are a potentially efficient strategy to reduce atmospheric carbon. The high inter-site and inter-species variability, partly related to differences in survival and growth, indicate the need for multi-site experimental designs in order to generalize the results of biomass estimation. [ABSTRACT FROM AUTHOR]

The Lacandon Maya of Chiapas, southern Mexico, have traditionally used a long fallow rotational slash-and-burn system for maize production in small clearings within tropical forest. Although successional processes usually lead to rapid restoration of abandoned fields, the invasive fern, Pteridium aquilinium (commonly known as Bracken), can block natural succession. The Lacandon are aware of this and use the fast-growing tree Balsa ( Ochroma pyramidale) to accelerate succession toward mature forest. We carried out a 12-month-long experiment in a Bracken-infested area to test the effectiveness of the Lacandon’s low-input restoration techniques. We found that we could successfully establish Balsa in plots dominated by Bracken using the Lacandon methodology. Their technique involves broadcasting large numbers of small seeds and applying traditional weeding techniques. After 12 months’ growth, Balsa reached a top height of over 6 m and basal areas of 4.1 (±0.3) m2/ha. We contrasted this low-cost traditional fallow management with more costly techniques involving transplanting Balsa seedlings and sowing directly in the experimental area. The results validated the effectiveness of the Lacandon method for directing succession and confirmed the general potential of Balsa as a facilitator in the restoration of degraded tropical forest areas. [ABSTRACT FROM AUTHOR]