## 4 Discussion  
The annual cork growth values found in this study (3-4 mm), were within the range of cork-ring widths reported at national level (2.2-4.8 mm) [19] and for southwestern Spain (1.9-5.3 mm) [18]. Moreover, for average stem diameter growth rates of 7-10 mm yr\({}^{-1}\), the estimated \"non-cork\" (wood) mean annual increments (1-2 mm), were in line with the range of values previously reported for cork oak raw wood-ring widths [6; 9] and for tree (wood)-ring width values reported for other oak species (1.0-2.5 mm) [21]. Along the 11 complete years of the cork production cycle, cork and stem showed similar variation patterns of radial growth (Figure 2). Cork growth revealed decreasing trends as expected from the immediately enhanced activity of the traumatic phellogen formed after cork harvesting and subsequent reduction [8]. The similarity of the stem diameter and cork growth curves indicates that the latter represents a large part of the radial increment but that the \"non-cork\" (wood) growth responds, as well, directly or indirectly, to cork harvesting. We know that taking measurements of stem diameter growth (encompassing wood and cork growths) and corresponding measurements of cork growth would allow us to derive wood growth. Wood growth is very difficult to measure in cork oak due to the extreme difficulty in obtaining tree-ring chronologies. These chronologies are only possible to achieve through stem cross-sections following tree filling, which is not allowed due to strict regulations enforced to protect cork oaks in cork-producing countries [6; 9]. The discrepancy of the lowest stem diameter growth in 2004, when a \"normal\" enhanced cork growth was still measured (Figure 2), might be explained by trees' investment on the new traumatic phellogen activity to produce cork layers in the first four post-harvest years [6; 22; 23], which forces a drastic shift in carbon allocation for that purpose at the expense of wood radial growth [6; 12; 13; 20; 24] and might severely impact stem diameter growth. Moreover, the 2005 drought was a prolonged drought initiated in 2004 (cf. Section 2.1) with a moderate drought in April-September [16]. This spring-summer drought seemed to affect stem diameter growth more than cork growth, which, in turn, was much more influenced by the previous winter-autumn temperatures and precipitation (Figure 3). For these reasons, it is noteworthy that, in 2004, the stem diameter growth decrease was mostly due to a reduction of \"non-cork\" (wood) growth rather than of cork growth. Furthermore, if it only depended on \"non-cork\" growth, stem radial growth would have a better recovery and returned to normal growth in 2005. However, drought might have harshly compromised cork growth and, consequently, stem diameter growth. In this study, similar but fewer and weaker correlations between climatic variables and stem diameter growth were found when compared with cork growth (Figure 3). However, in the drought year of 2009, increments of stem diameter were smaller, and deviations were more pronounced in stem diameter than in cork indices (Figure 2). This apparent paradox indicates that, by the end of the cork-production cycle, when trees have already reduced their energy allocation to cork growth after the cork harvest disturbance and returned to normal cork growth rates [16], the variation (decrease) of stem diameter increment was mostly due to a decreased in \"non-cork\" (wood) growth and suggests that the cambium activity is highly sensitive to climate factors, in agreement with what has been reported for tree-rings in _Quercus__l_x and other (deciduous) oaks [25; 26; 27]. In 2009, there was a moderate drought between May and August (cf. Section 2.1), which probably had a negative impact on cambium activity, much more influenced by the climatic factors prevailing in the current growth season (Figure 3).