Understanding the factors that determine the distribution of plant communities allows us to identify how climate and soil gradients influence the presence and abundance of species. In this paper, environmental parameters that determine species distribution along an altitudinal gradient were identified in the Chanchamayo valley. Using ordination and classification techniques, twelve 1 ha permanent plots were analyzed according to species affinities with climate and soil parameters. The results revealed three distinct plant communities, primarily governed by altitude (m), solar radiation (kJ m⁻² day⁻¹), and exchangeable acidity (Al³⁺H⁺, meq/100 g). This pattern confirms that, at more local scales, topographic and edaphic factors are determining factors in species assembly.

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Bosques y Gestión de Recursos Forestales

Universidad Nacional Agraria La Molina. Facultad de Ciencias Forestales. Departamento Académico de Manejo Forestal

The genus Cedrela contains timber species of great economic value that are ecologically and so- cially important in neotropical ecosystems. Phenological studies of Cedrela species have not been reported in the central Peruvian rainforest. The objective of this research was to preliminarily re- cord the phenological behavior of five sympatric species of the genus Cedrela in the Chanchamayo Valley (Junín), central Peru. The species evaluated were Cedrela angustifolia Moc. & Sessé ex DC., domatifolia W.Palacios, C. fissilis Vell., C. montana Turcz. and C. odorata L. Three phenophases were documented monthly: tender structures (budding), maturity and overmaturity (senescence) throughout one year (2021-2022) relating them to the dry and rainy seasons, and herbarium spe- cimens. Senescence and leaf fall occurred in the rainy (October to April) and dry (May to Septem- ber) seasons, flowe...

A new record of Cedrela domatifolia W. Palacios is presented in Chanchamayo Valley, department of Junin, which adds to 11 the number of Cedrela (Meliaceae) species recorded in Peru. The most notorious vegetative character of the species are the prominent domatia in the axils of the secondary nerves of blades. At floral characters, the petals are red to fuchsia, an uncommon feature in the genus.