Campo García, ADD.; Gualberto Fernandes, TJ.; Molina Herrera, A. (2014). Hydrologyoriented (adaptive) silviculture in a semiarid pine plantation: How much can be modified the water cycle through forest management?. European Journal of Forest Research. 133(55):879-894. doi:10.1007//s10342-014-0805-7. European Journal of Forest ResearchHydrology-oriented (adaptive) silviculture in a semiarid pine plantation: how much can be modified the water cycle through forest management?--Manuscript Draft-- Order of Authors Secondary Information:Abstract: Hydrology-oriented silviculture might adapt Mediterranean forests to climatic changes, although its implementation demands a better understanding and quantification on the water fluxes. The influence of thinning intensity (high, medium, low and a control) and its effect on the mid-term (thinned plots in 1998 and 2008) on the water cycle (transpiration, soil water and interception) and growth (Basal Area Increment, BAI) were investigated in 55-year-old Aleppo pine trees. Thinning enhanced a lower dependence of growth on climate fluctuations. The high intensity treatment showed significant increases in the mean annual BAI (from 4.1 to 17.3 cm2) that were maintained in the mid-term. Thinning intensity progressively increased the sap flow velocity (vs) in all cases with respect the control. In the mid-term, an increased functionality of the inner sapwood was also observed. Mean daily tree water use ranged from 5 (control) to 18 (high intensity) l tree-1. However, when expressed on an area basis, daily transpiration ranged from 0.18 (medium) to 0.30 mm (control), meaning that, in spite of the higher transpiration rates in the remaining trees, stand transpiration was reduced with thinning. Deep infiltration of water was also enhanced with thinning (about 30% of rainfall) and did no compete with transpiration, as both presented opposite seasonal patterns. The changes in the stand water relationships after ten years were well explained by the forest cover metric. The blue to green water ratio changed from 0.15 in the control to 0.72 in the high intensity treatment, with the remaining treatments in the 0. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 velocity (v s ) in all cases with respect the control. In the mid-term, an increased functionality of the inner sapwood was also observed. Mean daily tree water use ranged from 5 (control) to 18 (high intensity) l tree -1 . However, when expressed on an area basis, daily transpiration ranged from 0.18 (medium) to 0.30 mm (control), meaning that, in spite of the higher transpiration rates in the remaining trees, stand transpiration was reduced with thinning. Deep infiltration of water was also enhanced with thinning (about 30% of rainfall) and did no compete with transpiration, as both presented opposite seasonal patterns. The changes ...

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Marginal semi-arid forests in areas currently affected by climate change are a challenge to forest management, which has to focus on key functional traits that can effectively contribute to resistance under extreme drought. We studied the effects of thinning in a marginal forest by quantifying functional responses relating to growth, carbon and water fluxes. Two experimental plots were established, one thinned in 2012 and the other one left as a control. The environmental conditions varied substantially during the 4-year study period, although dry years predominated. There were signs of dieback in the control with a decreasing inter-annual trend in LAI, as opposed to the treated plots, where LAI by the end of the study almost reached pre-thinning levels. Sap flow and transpiration were greatly enhanced by the treatment, with thinned trees transpiring 22.4 l tree -1 day -1 in the growing season, about twice the control figures. The seasonal patterns of transpiration and soil moisture were uncoupled, indicating a contribution of deep groundwater to the former flux. In the control, limitations to water and carbon dynamics (canopy conductance) occurred at soil moisture values below 16%, whereas in the thinned trees these limitations appeared when soil moisture dropped below 10%.Overall, oaks' transpiration was enhanced with thinning to the point that stand-water use surpassed that of the control by the second half of the study period, averaging 24% of gross rainfall in both plots. Soil evaporation increased from 12 to 20% of gross rainfall after treatment in the overall period. The treatment had a profound watering effect in this marginal forest, led by fewer trees using the same amount of water as those in the untreated overstocked plot. This research may provide guidelines for ecohydrology-oriented silviculture in stands experiencing tree encroachment and transformation into shrublands that are more prone to global change-induced disturbances.

ElsevierGualberto-Fernandes, TJ.; Campo García, ADD.; Herrera Fernandez, R.; Molina Herrera, A. (2016). Simultaneous assessment, through sap flow and stable isotopes, of water use efficiency (WUE) In water-limited regions, adaptive management of forest and water relationships has been put 17 forward, to implement hydrology-oriented silviculture to reduce stand evapotranspiration and, 18 at the tree level, to improve growth and water use efficiency (WUE). The main goal of this 19 study was to evaluate the effect of thinning in the short and medium term on tree growth, 20 climate (drought) sensitivity, WUE performed using growth and sap flow measurements and 21WUEi performed using δ increased growth, but also changed the tree growth-precipitation relationships, with C trees 27 depending more on precipitation than thinned trees did. WUEi after thinning was significantly 28 affected only in the medium term, with C trees being more efficient (94.4 μmolCO2/molH2O) 29 than H98 trees (88.7), especially in dry spells (100.7). WUEi was found to increase when 30 precipitation decreased, regardless of the treatment. However, WUE increased sharply from C 31 was not consistent with our experimental data. Thus, the question of whether stable isotopes 37 can be used as a tool for addressing the ecophysiological impacts of thinning remains open. 38