What is shifting cultivation? Why did the Europeans decide to ban it?

In shifting cultivation, parts of forests are cut and burnt in rotation. Seeds are sown in the ashes after the first monsoon rains. The following prompted Europeans to ban it.
(i) They regarded this practice as harmful for forests.
(ii) They felt that the land which was used for cultivation every few years could not grow trees for railway timber.
(iii) When a forest was burnt, there was the added danger of the flames spreading and burning valuable timber.
(iv) Shifting cultivation also made it harder for the government to calculate taxes. Therefore, the government decided to ban shifting cultivation.