Even if it it is brief, a siege usually had very detrimental effects on the surrounding areas as the invading army "forages" for supplies. Also, the Romans were

Even if it it is brief, a siege usually had very detrimental effects on the surrounding areas as the invading army "forages" for supplies. Also, the Romans were not beyond indiscriminately slaughtering (not only plundering) or deporting populations that put up formidable resistance. E.g. Siege of Avaricum. Such depopulated areas were often awarded to other tribes or to retiring soldiers for resettlement. Caesar recorded it himself in his annals. They are not entirely reliable, but the essential points are probably true.