Can intensive silvicultural management minimize the effects of frost on restoration plantations in subtropical regions?

Temperature is one of the main factors that influence field establishment of forest species. In high-altitude tropical regions and in subtropical regions, the occurrence of frost represents an important restriction in the trajectory and continuity of ecological processes. Thus, we aimed to characterize frost damage in nine native forest species under different silvicultural management schemes in plantations for the restoration of a riparian forest area in southern Brazil. The experiment was carried out in the Quarta Colônia State Park, and seedlings of nine native tree species, representing the Subtropical Seasonal Forest. Frost damage was measured using a visual damage scale based on the frost damage experienced in the winter of 2016. In addition, to evaluate the resilience of the species, height and diameter data were collected over the duration of the experiment. The species Solanum mauritianum was classified as frost resistant; therefore, we propose that it should be recommended for cultivation in regions where frost events usually occur. The other species studied, both the pioneers, S. terebinthifolius, Enterolobium contortisiliquum, Ceiba speciosa, and Inga marginata, as well as the secondary ones, Actinostemon concolor, Trichilia elegans, T. claussenii, and Eugenia rostrifolia, were influenced by the silvicultural management schemes used. Plants managed under intensive silviculture showed lower levels of frost damage and higher survival rates.

Substrate and irrigation scheme on the growth of Parapiptadenia rigida (angico-vermelho) seedlings / Diferentes substratos e regimes de rega no desenvolvimento de mudas de Parapiptadenia rígida

ABSTRACT: Parapiptadenia rigida (angico-vermelho) is a native arboreal species widely found in central and southern Brazil and is indicated for restoration of degraded areas due to its high plasticity to light gradients and ease adaptation to degraded environments. However, there is still a lack of information on this species regarding the production of quality seedlings, as well as the rational use of the resources involved. Thus, the objective of this study was to evaluate the effects of different substrates and irrigation schemes in the development of P. rigida seedlings. The experimental design used was randomized blocks, in a factorial scheme with split plots, with four substrate formulations (100% peat; 80% peat + 20% carbonized rice husk (CRH); 60% peat + 40% CRH; 40% peat + 60% CRH) and six irrigation schemes (4; 8; 12; 16; 20 and 24mm.day-1). At 180 days after emergence, the following parameters were evaluated: height, stem diameter, height and stem diameter ratio, shoot dry weight, root dry weight, total dry weight and Dickson Quality Index. Use of substrate composed of 80% peat + 20% carbonized rice husk and/or 100% peat, combined with irrigation scheme of 4mm day-1, resulted in the best growth of P. rigida seedlings.

RESUMO: Parapiptadenia rígida (angico-vermelho) é uma espécie arbórea nativa amplamente encontrada na região central e sul do Brasil, é indicada para restauração de áreas degradadas em virtude de sua alta plasticidade a gradientes de luz e facilidade de adaptação a ambientes degradados. No entanto, a espécie ainda carece de informações no que se refere a produção de mudas de qualidade, bem como, a utilização de forma racional dos recursos envolvidos. Dessa forma, esse estudo teve por objetivo avaliar os efeitos de diferentes substratos e regimes de rega no desenvolvimento de mudas de P. rigida . O delineamento experimental utilizado foi blocos ao acaso, em esquema fatorial com parcela subdividida, considerando quatro formulações de substratos (100% turfa; 80% turfa + 20% casca de arroz carbonizada (CAC); 60% turfa + 40% CAC; 40% turfa + 60% CAC) e seis regimes de rega (4; 8; 12; 16; 20 e 24mm.dia-1). Aos 180 dias após a emergência, foram avaliados os seguintes parâmetros morfológicos: altura, diâmetro do coleto, relação altura e diâmetro do coleto, massa seca aérea, massa seca radicular, massa seca total e índice de qualidade de Dickson. Constatou-se que a utilização de substrato composto por 80% turfa + 20% casca de arroz carbonizada e/ou 100% turfa, combinado com o regime de rega de 4 mm.dia-1, proporcionam o maior crescimento das mudas de P. rigida.