The hard Siberian winters.
Settling usually causes conflicts between the new settlers and the indigenous people over control of territory, religion, politics, and commerce. Without more specifics (such as which group of settlers in which country/region) nothing more specific can be said.
they had to clear thick forests
They began conflicts over land
Planters were well to do people and farmers were poor class
land
conflicts began
Accidents with wepons
The Native American tribes, because the settlers pressured the Natives move off the land they wanted to settle.
As the colonies grew, so did the population of people in the back-country as the planters grew in prosperity and power threatened to shift from the low country. Before this time, the back country settlements and farms had remained small in comparison to the low country plantations. Therefore, the low countries interests were seen as being more important in the decisions made for the benefit of the colony. The back-country settlers were such an annoyance to the colonial government because they didn't want to be part of a government grounded in low country interests.
Mostly because th natives did not want to have their land stolen and be wiped out
Mostly settlers from Europe, while tribal conflicts existed the ways and means of those conflicts were not the same (generally speaking).
The home country settlers at Roanoke were from England, Jamestown settlers were also from England, and the Plymouth settlers were English Separatists, known as Pilgrims.