You will come across different types of obstacles when exploring the game locations: grass, bushes, plants of different kind, wooden logs, stones, etc. There are two ways to remove them:

1. By using energy. All you need to do is tap on the obstacle to see the energy cost, and then tap again to remove it:

You can find out how to acquire energy in this article.

2. By using dynamite. Dynamite allows you to remove multiple obstacles at once and clear a larger area of land.

To use it, tap on the dynamite, then place it near the area that you would like to clear, and tap the green button to activate it:

More information on this game mechanics is available under the link.