Why did Portugal increase its efforts to colonize Brazil around 1530?

Around 1530, Portugal shifted from a policy of neglect toward Brazil to one of active colonization due to several converging pressures and strategic concerns:

• Foreign Incursions: European rivals, particularly the French, began trespassing on Portuguese claims to harvest and ship brazilwood to Europe, threatening Portugal's control over the region.12
• Economic Shifts: The previously lucrative trade with Asia had entered a slump, prompting the Portuguese crown to look toward the Americas for new economic opportunities.2
• Spanish Success: The significant achievements of Spain in the Americas served as both an incentive for potential wealth and a geopolitical threat to Portuguese interests in the New World.2

In response to these stimuli, King John III initiated a systematic effort to assert authority. This included sending expeditions to expel interlopers and, beginning in 1533, dividing the coastline into 15 hereditary captaincies granted to donatários to encourage permanent settlement and economic development.123