Natural resources available on the city territory are: Woods, Fertile ground, Oil and Mines including coal.

In the view woods are marked in green, fertile ground in yellow, oil in black and mines in blue. For woods not only the amount of trees is important, but the territory under them marked in green as well. Territories with oil and coal usually can be found under rich woods which makes them sometimes hard to find.

When you create a district that in future will take care of specific industry, try to build industrial zones on a territory with most intense color which will make production more effective. Of course, you can place a withdrawal district on territory with no resources, but it will generate small income and eat a lot of resources.

Gathered wood and food is renewable but it gives smaller income. Additionally, this industry doesn't pollute territory where it resides.

Mines are not renewable so district mining oil on an oilfield after some time will use all its resources. Additionally, gathering is limited to a territory not much larger than the part under the buildings, so you must be prepared to invest more in that sort of industry.