Gradient analysis was used to determine factors driving small-scale variation of cloud forest communities harboring Magnolia dealbata, a threatened species and bioculturally relevant tree for the Chinantecan, Mazatecan, Nahuan, and Zapotecan ethnicities in southern Mexico. Particularly, we aimed to: (a) determine factors explaining major community gradients at different heterogeneity scales along a small-scale elevational gradient, (b) test the Decreasing and the Continuum hypotheses along elevation, and (c) classify vegetation to assist in identifying conservation priorities. We used a stratified random sampling scheme for 21 woody stands along a small-scale (352 m) elevational transect. Four main data matrices were used (presence-absence, density, basal area, and guild data). Through Non-metric Multidimensional Scaling (NMS), Principal Coordinates Analysis (PCoA), and distance-based Redundancy Analysis (db-RDA), we found that major community variation was explained by soil pH, displaying an outstanding vegetation discontinuity, separating the species-rich relic Oreomunnea-Ticodendron-stands from stands with higher importance values for M. dealbata. The high species richness observed was explained by a combination of the windward effect of dry-seasonal maximum cloud condensation gain and habitat differentiation-specialization, a phenomenon that may also explain the mid-peak hypothesis and ensure the survival of relic species. Sampling-truncation and conservation status also played a role in this. Our results do not support the Decreasing and Continuum hypotheses along elevation.

Three new species of Magnolia from lowland tropical rain forests of south-eastern Mexico are described and illustrated: Magnolia chimalapana, M. heribertoi and M. uxpanapana. We contrast these with morphologically similar species. The three new species are endemic to the Chimalapas region and are evaluated as critically endangered (CR). A map of published Magnolia species from the Chimalapas-Uxpanapa region and key for the Mexican species of M. section Talauma are also provided.

Background: Magnolia alejandrae is a critically endangered species and endemic to the Sierra Madre Oriental in northeastern Mexico. The abiotic requirements for its germination, such as light and temperature, are unknown. Hypotheses: White light and temperature fluctuations will promote the germination of M. alejandrae and seeds from site with higher humidity will have increased germination percentage. Study species: Magnolia alejandrae. Study sites and dates: El Farallón in the Jaumave municipality and Los San Pedros in the Güémez municipality, Tamaulipas, Mexico. May-June 2019. Methods: Four light-quality treatments (white, red, far-red and darkness) were evaluated, along with two temperature treatments: constant (18/18 ºC) and fluctuating temperatures (8/18 ºC) and two populations (El Farallón and Los San Pedros) on the germination of M. alejandrae. We used twenty seeds of the study species per experimental unit with five repetitions for each treatment. Results: Light quality influenced the germination of M. alejandrae seeds, having the highest germination (76 %) under white light, followed by 45 % under red light, 9 % under far-red and 5 % in darkness, demonstrating that the seeds of this species are neutral photoblastic. Temperature fluctuation (8/18 °C) enhanced germination of M. alejandrae more than constant temperature (18/18 °C). Conclusions: M. alejandrae seeds respond differentially to light quality and temperature, which has important implications in the reforestation and conservation of the species.

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Background: Forest vegetation is used daily to sustain basic family needs and incomes in rural communities. Harvesting vegetative regrowth through coppice, a traditional method to produce firewood and charcoal, guarantees permanent forest cover and rapid regrowth. However, a narrative predominates that sanctions this use and stigmatizes those who produce it, attributing the cause of forest degradation and deforestation. In Mexico there are few studies focusing on this type of forest management and its effects. Objective: To characterize the small forest fragments managed traditionally by coppice in agroforestry plots of Zongolica mountain range, Veracruz, México. Methodology: Forest survey in 16 circular sites measuring tree structure, species composition and regeneration, covering 1 hectare sampled. Results: Eleven tree species used for fuelwood were recorded, two with protection status; Quercus with five species, Q. laurina dominated 94% and Q. rugosa 63% among the sites. The average diameter 29.45±0.68 cm, and total basal area of 77.17 m2/ha-1; regeneration occurs by sprouting from the base of the stump with cutting cycles varying 5 to 20 years. Implications: The structural and composition heterogeneity within these agroforestry plots represent a potential to incorporate this management as a productive restoration strategy. Conclusions: These rural forests are maintained through traditional practices, revealed a local knowledge on tree species and are important for family livelihoods as source of raw material for charcoal and firewood. Attending the development of these forest fragments would ensure management cycles that provide the biomass production required by their owners, while conserving tree diversity at landscape level.