Why were the Kalangas of Java considered an important community?

Why were the Kalangas of Java considered an important community? What compelled them to rebel against the Dutch and to what result?

Kalangas community of Java were very important due to their expertise in forest cutting and shifting cultivation. Their importance could be realised by the fact that they were divided into two parts when Mataram Kingdom of Java was split into two parts.
Without their expertise, harvesting teak and building palaces were impossible.
The Kalangas rebelled against Dutch for the following reasons
(i) Dutch introduced forest laws to restrict villager’s access to forest.
(ii) Forest laws specified that wood could be only used for making river boats and houses.
(iii) Villagers were punished for grazing cattle or transporting wood without a permit.
(iv) Imposition of rents on land being cultivated which was later exempted on condition of free supply of labour and buffaloes.
The Kalangas in 1770 revolted against the Dutch. But their revolt was not successful as they were brutally suppressed by the Dutch forces.