Assessment of forest water-use (WU) is undoubtedly important and necessary, especially
in water scarcity areas that are already suffering the main negative impacts of climate
change. However, instead of just determining how much water is used by a forest, it is
also important to evaluate how forest-WU responds to forest management practices such
as thinning, a widely recognized alternative to promote improvements in the hydrologic
balance while maintaining or improving forest resilience. Thus, this thesis proposes three
integrated studies performed in an area of Aleppo pine subject to experimental thinning
in Eastern Spain. The first study was modelling an artificial neural network (ANN) to
estimate daily WU independently of forest heterogeneity provided by thinning. Stand
WU was accurately estimated using climate data, soil water content and forest
cover (correlation coefficient, R: 0.95; Nash-Sutcliffe coefficient, E: 0.90 and rootmean-square
error, RMSE: 0.078mm/day). Then the ANN modelled was used for gapfilling
when needed and those results were used in the following studies. The secondly
study addressed the question of how tree-growth, WU and water balance changed as a
consequence of thinning. To this end, the influence of thinning intensity and its effect at
short-term (thinned in 2008) and at mid-term (thinned in 1998) on the water-balance
components and tree-growth were investigated. The high-intensity thinning treatment
showed significant increases in mean annual tree-growth from 4.1 to 17.3 cm2
yr
-1
, a rate
which was maintained in the mid-term. Mean daily WU ranged from 5 (control) to 18
(high intensity thinning) l tree-1
. However, when expressed on stand basis, daily WU
ranged from 0.18 (medium intensity thinning) to 0.30 mm (control plot), meaning that in
spite of the higher WU rates in the remaining trees, stand WU was reduced with thinning.
Large differences were found in the water balance components between thinning plots
and control. These differences might have significant implications to maintain forest
resilience, and improve forest management practices. The third study, brings forth two
interesting points and their responses to thinning, WU and intrinsic water-use efficiency
(WUEi). First, the relationships between growth and climate were studied at mid-term in
order to identify if thinning can improve forest resilience. Second, the relationships
between WU and WUEi was explored to identify how these factors were affected by
thinning at short-term. A substantial limitation of tree-growth imposed by climatic
conditions was observed, although thinning changed the tree-growth-precipitation
relationships. Significant differences in WUEi were found after thinning at mid-term,
however no significant difference was observed at short-term. Despite this, in general
WUEi decreased when precipitation increased, with different slopes for each thinning
intensity. Different patterns of the relationship between WU and WUEi were found,
being positive for thinned plots and negative for control plot at short-term. Finally this
thesis suggest that thinning in Aleppo pine plantations is effective in changing the
relationships between WU and WUEi, furthermore, this thesis introduces a novel
contribution by looking at the inter-related effects on growth, WU, WUEi and water
balance in Mediterranean forest subject to thinning. / Gualberto Fernandes, TJ. (2014). Water-oriented management in forest plantations: combining hydrology, dendrochronology and ecophysiology [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48476 / TESIS
| Identifer | oai:union.ndltd.org:upv.es/oai:riunet.upv.es:10251/48476 |
| Date | 09 December 2015 |
| Creators | Gualberto Fernandes, Tarcisio Jose |
| Contributors | Campo García, Antonio Dámaso del, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient |
| Publisher | Universitat Politècnica de València |
| Source Sets | Universitat Politècnica de València |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/acceptedVersion |
| Rights | http://rightsstatements.org/vocab/InC/1.0/, info:eu-repo/semantics/openAccess |
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