ABSTRACT Native species planted in areas previously occupied by degraded pasture can play an important role in biomass supply and atmospheric carbon sequestration. Evaluating the performance of native species in different planting spacings becomes important for forestry and the management of new species with economic potential. Schizolobium parahyba var. amazonicum is a non-traditional species in the southeastern region of Brazil and it was established in pasture areas to evaluate growth, biomass, and carbon stock. Five planting spacings (3 m x 2 m, 3 m x 3 m, 4 m x 3 m, 4 m x 4 m, and 5 m x 5 m, in monoculture) were tested in 9 experimental plots. The biomass of the shoot and root, as well as the carbon content, were obtained by the direct method. The biomass varied 31.4 and 52.9 kg tree-1 in the spacing 3 m x 2 m and 5 m x 5 m, respectively. The greater carbon stock was observed in the lower spacing (19.43 Mg ha-1), 50% higher than in the larger spacing. The spacing did not influence the biomass and carbon stock in the roots per unit area. The performance of the species should be monitored at advanced ages given the different responses to planting spacing and competition between plants.

RESUMO Espécies nativas plantadas em locais anteriormente ocupados por pastagem degradada podem desempenhar um papel importante no suprimento de biomassa e no sequestro de carbono atmosférico. Avaliar o desempenho das espécies nativas em diferentes espaçamentos de plantio se torna importante para a silvicultura e o manejo de novas espécies com potencial econômico. Schizolobium parahyba var. amazonicum é uma espécie não tradicional na região sudeste do Brasil, e foi estabelecida em área de pastagem com objetivo de avaliar o crescimento, a biomassa e o estoque de carbono. Foram testados cinco espaçamentos de plantio em monocultivo (3 m x 2 m, 3 m x 3 m, 4 m x 3 m, 4 m x 4 m e 5 m x 5 m) com 9 parcelas experimentais. A biomassa da parte aérea e radicular, bem como o teor de carbono foram obtidos por meio do método direto. A biomassa variou 31.4 and 52.9 kg árvore-1 nos espaçamentos 3 m x 2 m e 5 m x 5 m, repectivamente. O maior estoque de carbono foi observado no espaçamento mais adensado (19.43 Mg ha-1), sendo 50% maior do que no espaçamento menos adensado. O espaçamento não influenciou a biomassa e o estoque de carbono nas raízes por unidade de área. O desempenho da espécie deveria ser monitorado em idades avançadas dado as diferentes respostas ao espaçamento de plantio e competição entre plantas.

ABSTRACT Cariniana pyriformis is a native arboreal of Colombia with high forestry potential in pure plantations and agroforestry systems of Theobroma cacao. In an agricultural nursery with plastic cover, production and seedling quality were evaluated with a complete randomized block design and three replications using three plastic containers (treatments): bags (1700 cm3), tube trays (700 cm3) and multicellular trays (650 cm3). Between 120 (bags) and 135 (tube trays) days after sowing (das), the seedlings reached 25 cm in height and 3 mm in stem diameter. The shoot dry mass (p= 0.0179) and root dry mass (p= 0.0327) of seedlings at 160 das were higher in the bags as compared to seedlings grown in the tube trays. In parallel, the production of C. pyriformis seedlings in multicellular trays achieved quality indexes very similar to those obtained employing the bags, but with a 60% reduction in the cost per seedling.

RESUMEN Cariniana pyriformis es una arbórea nativa de Colombia con elevado potencial en plantaciones puras y sistemas agroforestales de Theobroma cacao. En vivero agrícola con cobertura plástica, se evaluaron la producción y calidad de plántulas con un diseño de bloques completos al azar y tres repeticiones empleando tres contenedores plásticos (tratamientos): bolsa (1700 cm3), bandeja portatubete (700 cm3) y bandeja multicelda (650 cm3). Entre los 120 (bolsa) y 137 (bandeja portatubete) días después de siembra (dds), las plántulas alcanzaron los 25 cm de altura y 3 mm de diámetro de cuello. El peso seco de la parte área (p= 0,0179) y peso seco del sistema radicular (p= 0,0327) de las plántulas a los 160 dds fueron superiores en la bolsa en comparación con las plántulas crecidas en la bandeja portatubete. En paralelo, la producción de plántulas de C. pyriformis en bandeja multicelda presentó índices de calidad muy similares a la bolsa, pero con una reducción en el costo por plántula entorno al 60%.

Abstract Lecythis tuyrana is an endemic tree in the Magdalena River basin in Colombia with unexplored forestry, nutraceutical, medicinal and nutritional potential. In the nursery, two experiments on the production of L. tuyrana seedling were evaluated. In the first experiment, three container volumes and the absence or presence (3 g L-1) of a controlled-release fertilizer (CRF) were evaluated. The use of tube trays (700 cm3) and CRF significantly increased the height, biomass, and Dickson quality index of the seedlings (between 28 to 61 %) compared to those not fertilized. In the second experiment the light acclimation of seedlings was evaluated in two environments: full sun at 50% and 100%. There were no changes in photosynthetic rates when the seedlings were kept in the shade for longer, but there was a lesser accumulation of biomass. A light intensity of approximately 1 600 µmol m-2 s-1 is considered optimal for L. tuyrana seedling.

Abstract The effect of hydrogel (0, 3, 6, and 9 g per seedling) on the survival and growth of Cariniana pyriformis seedlings under different water regimes (absence of irrigation, 60% and 100% field capacity) in a sandy loam soil was assessed. The experiment was carried out in an agricultural nursery with drip irrigation, implementing a completely randomized block design in a split-plot scheme. After 20 weeks of evaluation in both treatments with irrigation, the maximum dose showed a slight increase (9%) in stem diameter and seedling height compared with the control treatment, although the aerial and root dry biomass did not show differences. For the treatment without irrigation, the survival had a linear response with increasing doses, from 24% (0 g per seedling) to 65% (9 g per seedling). C. pyriformis responds positively to hydrogel when a severe water deficit occurs.