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Publicação
O Efeito Das Alterações Climáticas na Produtividade da Floresta de Pinheiros no Pinhal de Leiria nos Séculos XX e XXI
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Orientador(es)
Resumo(s)
Atualmente, um dos grandes desafios a nível mundial é lidar com as alterações climáticas. Algumas
das muitas consequências negativas deste fenómeno são o aumento da temperatura, alterações no
regime de precipitação, o aumento do risco de desertificação e de incêndios florestais, e o aumento de
eventos climáticos extremos. Apesar disto, tem sido constatado um aumento na produtividade primária
líquida e na biomassa nas florestas, em contextos onde a disponibilidade de água não é fator limitante
ao crescimento.
Nesta dissertação foi então realizada uma análise dendrocronológica de várias amostras de Pinus
pinaster Ait. (pinheiro-bravo) provenientes da Mata Nacional de Leiria (MNL) recolhidas em 2013, 2016,
2017 e 2022, com a finalidade de avaliar como os efeitos das alterações climáticas na temperatura e
na precipitação afetaram o crescimento radial das árvores nos seus primeiros 20 anos de vida. A MNL
é uma floresta costeira cuja espécie vegetal dominante é o pinheiro-bravo. Para além do seu valor
histórico e simbólico, contribui positivamente a nível económico, social e ambiental, principalmente com
a produção de madeira e extração de resina, proteção das zonas costeiras, regulação do clima e como
sumidouro de carbono.
O período de análise vai desde 1887 até 2021, tendo as amostras sido divididas em grupos de
idades diferentes para se perceber quais as principais divergências no padrão de crescimento de
árvores que germinaram em décadas distintas. Foi calculado o incremento médio em área basal de
cada grupo a partir das espessuras dos anéis de crescimento, e concluiu-se que desde a década de
90 as árvores da região têm tido em média um crescimento radial superior. Por outro lado, foi feita a
análise dendroclimatológica, para aferir sobre o impacto do clima, correlacionando as cronologias aos
dados mensais de precipitação e de temperatura. Foram constatadas poucas correlações
estatisticamente significativas, não se podendo afirmar que existiu um comportamento específico da
espécie.
Currently, one of the major challenges worldwide is dealing with climate change. Some of the many negative consequences of this phenomenon are the increase in temperature, changes in the precipitation regime, the increased risk of desertification and forest fires, and the increase in extreme weather events. Despite this, an increase in net primary productivity and biomass in forests has been observed, when water is not a limiting factor of growth. In this dissertation, a dendrochronological analysis of several samples of Pinus pinaster Ait. (maritime pine) from the Leiria National’s Forest (LNF) collected in 2013, 2016, 2017 and 2022, in order to assess how the effects of climate change on temperature and precipitation affected the radial growth of trees in their first 20 years of life. The LNF is a coastal forest whose dominant plant species is maritime pine. In addition to its historical and symbolic value, it contributes positively at an economic, social and environmental level, mainly with the production of wood and resin extraction, protection of coastal areas, climate regulation and as a carbon sink. The analysis period ranges from 1887 to 2021, with the samples being divided into different age groups to understand the main differences in the growth pattern of trees that germinated in different decades. The average increment in basal area of each group was calculated from the ring width, and it was concluded that since the 90's the trees in the region have had, on average, a higher radial growth. On the other hand, a dendroclimatological analysis was carried out to assess the impact of the climate, correlating the tree ring chronologies with the monthly data of precipitation and temperature. Few statistically significant correlations were found, not being able to state that there was a specific behavior of the species.
Currently, one of the major challenges worldwide is dealing with climate change. Some of the many negative consequences of this phenomenon are the increase in temperature, changes in the precipitation regime, the increased risk of desertification and forest fires, and the increase in extreme weather events. Despite this, an increase in net primary productivity and biomass in forests has been observed, when water is not a limiting factor of growth. In this dissertation, a dendrochronological analysis of several samples of Pinus pinaster Ait. (maritime pine) from the Leiria National’s Forest (LNF) collected in 2013, 2016, 2017 and 2022, in order to assess how the effects of climate change on temperature and precipitation affected the radial growth of trees in their first 20 years of life. The LNF is a coastal forest whose dominant plant species is maritime pine. In addition to its historical and symbolic value, it contributes positively at an economic, social and environmental level, mainly with the production of wood and resin extraction, protection of coastal areas, climate regulation and as a carbon sink. The analysis period ranges from 1887 to 2021, with the samples being divided into different age groups to understand the main differences in the growth pattern of trees that germinated in different decades. The average increment in basal area of each group was calculated from the ring width, and it was concluded that since the 90's the trees in the region have had, on average, a higher radial growth. On the other hand, a dendroclimatological analysis was carried out to assess the impact of the climate, correlating the tree ring chronologies with the monthly data of precipitation and temperature. Few statistically significant correlations were found, not being able to state that there was a specific behavior of the species.
Descrição
Palavras-chave
Pinus pinaster Aiton dendrocronologia alterações climáticas