What is the reason for the massive partisan movement? what is its significance?

The following reasons for the mass partisan movement during the Great Patriotic War can be distinguished:

-The brutal occupation policy in relation to the civilian population, it helped the partisans and replenished their detachments.

-Experience of underground work with the Bolsheviks.

-Forest and swamp areas behind the front line, where the Red Army men and commanders sometimes retreated, they also began to partisan.

-Creation in 1942 of the Central Headquarters of the Partisan Movement.

The significance of the partisan movement was that the partisans diverted significant forces of the German army to themselves, they blew up many bridges and derailed a huge number of trains.