Correct - this is a magnificent Blue Gum specimen (
Eucalyptus globulus) - see https://en.wikipedia.org/wiki/Eucalyptus_globulus.
Blue Gums were planted extensively across northern Spain and adjoining areas of Portugal some 30 or 40 years ago, presumably for their hardwood timber value (saw logs, chip wood or poles). Blue gums are fast growing, and produce long straight-grained sawlogs suitable for flooring, framing timber and furniture.
What was probably not appreciated at the time was the increased fire risk that eucalypt plantations bring - a consequence ot the increased timber production, the fallen bark and leaves providing fuel at the ground, and the highly flammable eucalyptus oil in the leaves. We in Australia are accustomed to the risk and manage it with varying degrees of success. I recall severe forest fires in northen pain and Portugal in 2017 and 2018 (and no doubt many years) with some deaths.
As with any 'foreign' monoculture, this comes at a cost to the local environment, and it is up to the sociery of the day (and their government) to make choices on environmental and heritage protection, public safety, and jobs and economic activity.