## 2 The Montado Ecosystem
### The Components of the Montado
#### 2.2.2 Trees
[53], in a study carried out in Montado, in the Evora region, in which they compared soil fertility and the production and quality of pasture under and outside the canopy of Holm oak trees, reported that soil fertility under the canopy is superior compared to that of the soil outside the canopy. These authors found OM values of 2.3% under the canopy and only 1.8% outside the canopy; for P\({}_{2}\)O\({}_{5}\), the values found under and outside the canopy were 39.8 mg/kg and 28 mg/kg, respectively; for K\({}_{2}\)O, the values found were 146 mg/kg and 72 mg/kg under and outside the canopy, respectively. In another study of Montado, [PERSON] et al. [32] report that, in terms of productivity (green matter (GM) and DM), the canopy had a positive effect in autumn, while in winter and spring, the highest productivity was seen outside the canopy. These authors obtained average values of GM in autumn of 7250 kg/ha and 6850 kg/ha, under and outside the canopy, respectively; in winter, they obtained average values of GM of 1085 kg/ha and 1530 kg/ha, under and outside the canopy, respectively; in spring, they obtained average values of GM of 6250 kg/ha and 1235 kg/ha, under and outside the canopy, respectively. Regarding productivity in terms of kg/ha DM, [PERSON] et al. [53] obtained average values in autumn of 1050 and 1000 kg/ha, under and outside the canopy, respectively; in winter, these values were 1750 and 2050 kg/ha, under and outside the canopy, respectively; in spring, these values were 1700 and 4300 kg/ha, under and outside the canopy, respectively. These authors also mention that grazing under the canopy is of higher quality (higher crude protein--CP) than grazing outside the canopy. Thus, for the % CP in the pasture DM, [PERSON] et al. [53], in autumn, found values of 23.6% and 18.5% under and outside the canopy, respectively; in winter, these values were 17.9% and 16.5%, under and outside the canopy, respectively; in spring, CP was 14.8% and 8.25%, under and outside the canopy, respectively. The canopy structure is a relevant factor in the competition for light [50], varying with tree age and species [54]. In the Mediterranean region, competition for water is usually another limiting factor for pasture growth [51; 55], particularly in locations with dry summers when high temperatures are recorded [50]. The canopy also modifies the soil and air temperature [30]. According to these authors, on warm days, the air temperature was significantly lower under the canopy when compared with that obtained outside the canopy, finding values of 14.2 \({}^{\circ}\)C, 16.1 \({}^{\circ}\)C, 16.5 \({}^{\circ}\)C, and 16.6 \({}^{\circ}\)C at 1, 10, 20, and 30 m away from the trunk of the tree, respectively. On cold days, the opposite happened, i.e., air temperature was higher under the canopy than outside. The same was verified for soil temperature, which was higher under the canopy on cold days and lower on hot days. On hot days, the maximum soil temperature under the canopy was 29.6 \({}^{\circ}\)C, while outside, it was 46 \({}^{\circ}\)C [30]. The type of management chosen for grazing may be necessary for containing the harmful effects on trees in their juvenile phase. Factors such as the stocking rate, the rotation of livestock species by plot, the length of stay in each one, and the composition and amount of supplements provided to animals should be evaluated properly [45]. According to [PERSON] et al. [45], the agricultural practices and the conduct of grazing animals that have occurred in Montado are not the most appropriate for the processes of the dispersal and establishment of young plants and their development into adult trees; however, the same authors also infer that grazing has a positive effect in denser Montados, since the animals remove the herbaceous stratum, reduce the shrub stratum, and, consequently, decrease the susceptibility to fire of this ecosystem.