31 documents found, page 1 of 4
A critical thermal transition driving spring phenology of Northern Hemisphere c...
Huang, Jian-Guo; Zhang, Yaling; Wang, Minhuang; Yu, Xiaohan; Deslauriers, Annie; Fonti, Patrick; Liang, Eryuan; Mäkinen, Harri; Oberhuber, WalterDespite growing interest in predicting plant phenological shifts, advanced spring phenology by global climate change remains debated. Evidence documenting either small or large advancement of spring phenology to rising temperature over the spatio-temporal scales implies a potential existence of a thermal threshold in the responses of forests to global warming. We collected a unique data set of xylem cell-wall-t...
Tropical tree growth driven by dry-season climate variability
Zuidema, Pieter A.; Babst, Flurin; Groenendijk, Peter; Trouet, Valerie; Abiyu, Abrham; Acuña-Soto, Rodolfo; Adenesky-Filho, EduardoInterannual variability in the global land carbon sink is strongly related to variations in tropical temperature and rainfall. This association suggests an important role for moisture-driven fluctuations in tropical vegetation productivity, but empirical evidence to quantify the responsible ecological processes is missing. Such evidence can be obtained from tree-ring data that quantify variability in a major ve...
Environment Controls Seasonal and Daily Cycles of Stem Diameter Variations in P...
Vieira, Joana; Campelo, Filipe; Nabais, CristinaTree growth takes place at different time scales ranging from hours to days. To understand growth responses to climate, continuous high-resolution measurements of tree diameter variations are needed, which are usually obtained with automatic dendrometers. Here, we monitored stem diameter increment of Quercus faginea Lambert growing in central Portugal to determine the effect of climate on daily and seasonal gro...
Extreme Growth Increments Reveal Local and Regional Climatic Signals in Two Pin...
Vieira, Joana; Nabais, Cristina; Campelo, FilipeTree rings are valuable proxies of past climate that allow inferring past growth responses to climate variability and extreme events, which is only possible considering that the relationship between tree growth and environmental conditions is linear and stable over time. However, in the last decades, divergent growth patterns have been observed in trees from the same forest stand, while unprecedented growth con...
Seasonal adjustment of primary and secondary growth in maritime pine under simu...
Vieira, Joana; Moura, Mikael Alvites; Nabais, Cristina; Freitas, Helena; Campelo, FilipeKey message Reducing irrigation by up to 75% in spring decreased primary and secondary growth in Pinus pinaster Aiton saplings, whereas an extra irrigation in September prompted secondary growth, confirming the high plasticity of xylogenesis in this species. Context Water availability is the main limiting factor for plant growth and forest productivity in drought-prone environments, such as the Mediterranean re...
Actividades enzimáticas antioxidativas em Cistus Ladanifer L. provenientes de á...
Santos, Erika; Abreu, Maria Manuela; Saraiva, Jorge; Nabais, CristinaAvaliou-se a actividade das enzimas antioxidativas (catalase, peroxidase e superóxido dismutase) e as concentrações em As, Cu, Pb e Zn nas folhas de duas populações de Cistus ladanifer L. colhidas, na Primavera e no Verão, em solos não contaminados em elementos vestigiais (Caldeirão e Pomarão) e com condições climáticas diferentes. Nos solos das duas áreas, as concentrações totais e disponíveis (extracção com D...
Dendrochronology and climate in the Brazilian Atlantic Forest: Which species, w...
Fontana, Cláudia; Reis-Avila, Gabriela; Nabais, Cristina; Botosso, Paulo Cesar; Oliveira, Juliano MoralesAs dendrochronology noticeably increased in tropical regions during the last three decades, some general patterns could emerge from comprehensive analyses of case studies. Here, we investigated the state of dendrochronology’s contributions to the bioclimatology of wood species in the Brazilian Atlantic Forest (AF). We asked: Which species and sites had cross-datable growth-ring series suitable for bioclimatic i...
CENTENÁRIO DA JUBILAÇÃO DE JÚLIO HENRIQUES: RECORDAR O HOMEM, CELEBRAR A OBRA. ...
Santos, Ana Luísa; Silva, Ana Margarida Dias da; Nabais, Cristina; Coutinho, António Xavier Pereira; Sales, Fátima; Gonçalves, M. TeresaNota Introdutória Bem-vindos ao Colóquio e Exposição “Centenário da jubilação de Júlio Henriques: recordar o homem, celebrar a obra”. Nos seus 728 anos de história, a Universidade de Coimbra testemunhou a passagem de muitas figuras ilustres. Na área da Botânica, o Prof. Júlio Henriques deixou um legado imenso, cuja jubilação, em 1918, hoje comemoramos. Júlio Augusto Henriques (15-01-1838, Cabeceiras de Basto; 0...
Dendrochronology of maritime pine in the middle of the Atlantic Ocean
Vieira, Joana; Campelo, Filipe; Nabais, CristinaThe Azores Archipelago, located in the North Atlantic Ridge, experiences heavy rainfall and mild temperatures with weak seasonal differences due to oceanic influence. To our knowledge, there have been no dendrochronological studies in the Azores. The aim of this study is to explore the dendrochronological potential of Pinus pinaster Ait. growing in this archipelago and to determine what limiting factor is regul...
Rain exclusion affects cambial activity in adult maritime pines
Vieira, Joana; Nabais, Cristina; Rossi, Sergio; Carvalho, Ana; Freitas, Helena; Campelo, FilipeDrought frequency and intensity are expected to increase in the Mediterranean basin with unforeseen impacts on forest ecosystems. In this study, we investigated the effect of a rain exclusion experiment on the growth dynamics of adult maritime pine trees. The rain exclusion experiment took place from March to October 2014. Cambial activity and xylem development was weekly monitored in five treated and five cont...