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Regeneração Natural Da Azinheira No Concelho De Estremoz
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A regeneração natural da azinheira (Quercus rotundifolia) no concelho de Estremoz é um
tema bastante relevante devido aos desafios que este processo enfrenta. As consequências das
alterações climáticas indicam que se dificulte o processo de regeneração natural dos povoa-
mentos desta espécie de grande importância a nível nacional.
Em muitos terrenos onde a prática agrícola e pastoreio intensivo foram abandonados,
tem sido registada uma regeneração natural de azinheira. O objetivo desta dissertação é ana-
lisar a evolução espácio-temporal da regeneração natural da azinheira no concelho de Estre-
moz, analisando a evolução da ocupação do solo. A regeneração natural da azinheira é crucial
para os montados, por ter funções de conservação do solo, regulação hídrica e proteção da
biodiversidade.
Nesta dissertação selecionou-se o caso de estudo do concelho de Estremoz, no Alentejo.
Foram realizadas medições de 15 parcelas, sendo que algumas destas se encontravam fora do
concelho de Estremoz, onde foram medidos o diâmetro à altura do peito e altura de fuste das
árvores nelas presentes. De forma a realizar uma correlação entre a biomassa obtida através
do trabalho de campo e o Normalized difference vegetation index (NDVI) foram utilizados valores
de parcelas que se encontravam fora do concelho de Estremoz. Foi analisada a evolução das
Cartas da Ocupação e Uso do Solo (COS) de 1995, 2007 e 2018, de forma a perceber as altera-
ções de usos do solo e também estudar as transições que ocorreram relativamente às áreas
ocupadas por azinheiras. Foram realizados modelos de regressão entre os valores de biomassa
e o valor médio de NDVI de três meses diferentes, agosto de 2015, agosto de 2023 e fevereiro
de 2024.
O estudo demonstrou um declínio das áreas de pastagem e agricultura, com aumento
das vinhas e florestas de sobreiro no Alentejo. A área ocupada por azinheiras diminuiu leve-
mente, sendo que algumas possíveis causas foram práticas agrícolas intensivas e alterações
climáticas. O NDVI indicou que comparando agosto de 2023 com agosto de 2015 houve uma
melhoria na densidade da vegetação.
The natural regeneration of the holm oak (Quercus rotundifolia) in the municipality of Estremoz is a very relevant topic due to the challenges this process faces. The consequences of climate change are likely to disrupt the process of natural regeneration of this species, which has great national importance. Many areas where intensive farming and grazing have been abandoned have noticed some natural regeneration of holm oak. The aim of this dissertation is to compare with previ- ous years in order to see the evolution throughout the years. The natural regeneration of holm oaks is crucial for ecosystems, as it conserves soil, regulates water and protects biodiversity. In this dissertation, the case study of the municipality of Estremoz, in the Alentejo, was selected. Measurements were taken on 15 plots, where the diameter at breast height and split trunk height were measured on the trees present. To correlate the value of the biomass calcu- lated with the Normalized Difference Vegetation Index (NDVI), values from plots outside the municipality of Estremoz were used. The evolution of the 1995, 2007 and 2018 Land Use and Occupation Maps (COS) were also analyzed in order to understand the changes in these maps and also to study the transitions that have occurred in terms of the areas occupied by holm oaks. Regression models were run between biomass and NDVI values from three different months, August 2015, August 2023 and February 2024. The study showed a decline in pasture and agricultural areas, with an increase in vine- yards and cork oak forests in the Alentejo. The area occupied by holm oaks decreased slightly, with some possible causes being intensive agricultural practices and climate change. The NDVI indicated that comparing August 2023 with August 2015 there was an improvement in vegetation density.
The natural regeneration of the holm oak (Quercus rotundifolia) in the municipality of Estremoz is a very relevant topic due to the challenges this process faces. The consequences of climate change are likely to disrupt the process of natural regeneration of this species, which has great national importance. Many areas where intensive farming and grazing have been abandoned have noticed some natural regeneration of holm oak. The aim of this dissertation is to compare with previ- ous years in order to see the evolution throughout the years. The natural regeneration of holm oaks is crucial for ecosystems, as it conserves soil, regulates water and protects biodiversity. In this dissertation, the case study of the municipality of Estremoz, in the Alentejo, was selected. Measurements were taken on 15 plots, where the diameter at breast height and split trunk height were measured on the trees present. To correlate the value of the biomass calcu- lated with the Normalized Difference Vegetation Index (NDVI), values from plots outside the municipality of Estremoz were used. The evolution of the 1995, 2007 and 2018 Land Use and Occupation Maps (COS) were also analyzed in order to understand the changes in these maps and also to study the transitions that have occurred in terms of the areas occupied by holm oaks. Regression models were run between biomass and NDVI values from three different months, August 2015, August 2023 and February 2024. The study showed a decline in pasture and agricultural areas, with an increase in vine- yards and cork oak forests in the Alentejo. The area occupied by holm oaks decreased slightly, with some possible causes being intensive agricultural practices and climate change. The NDVI indicated that comparing August 2023 with August 2015 there was an improvement in vegetation density.
Descrição
Palavras-chave
Azinheira Regeneração Natural Montados Biomassa