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Publicação
Influência de uma árvore isolada de freixo (Fraxinus angustifolia Vahl ) no microclima num lameiro em Trás-os-Montes
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Orientador(es)
Resumo(s)
Changes in microclimate caused by an
isolated ash tree (Fraxinus angustifolia
Vahl) were assessed in a pasture land close
to Bragança (41º 46’ 55’’ N; 6º 24’ 51’’ W;
510m de altitude), in Northeastern Portugal),
where climate is Csb according to
Köppen. The experimental site was locatedin the bottom of a small valley, and soils
mostly fit the Eutric Fluvisols. Solar radiation,
rainfall, and air and soil temperature
were measured during three years beneath
the tree canopy and in the open. Results
showed that the microclimate conditions
under the tree canopy were significantly
different from those in the open. This is
due to solar radiation interception (about
25 a 35% in winter and 55 a 65% in summer)
and the interception of about 40% of
the gross rainfall (52-56% during May-
-October, and 35% when the foliage was
absent). Mean air temperatures under the
canopy were higher than those in the open,
with the differences being greater at nigth,
reaching about 3ºC in summer and 5ºC in
winter. Compared to the open, mean soil
temperatures in winter were higher (about
1ºC at 20 cm depth) beneath the canopy,
but were smaller (1ºC at 2 cm depth) in
summer. Amplitudes of soil and air temperature
were lower under the tree canopy
than in the open. These microclimate conditions
under the canopy may favour both
the herbaceous biomass production and the
earlier development of herbaceous at the
end of winter.
Descrição
Palavras-chave
fraxinus angustifolia natural pasture microclimate Portugal lameiro microclima
Contexto Educativo
Citação
"Revista de Ciências Agrárias". ISSN 0871-018X. 30:2 (2007) 233-245
Editora
Sociedade de Ciências Agrárias de Portugal