As you explore the islands, you will need to chop down plenty of bushes. Most of the time, when you clear a bush you will get sticks, but some bushes will also give you extras like energy, caoutchouc or a spike.
Note that while in general bushes do regenerate, the ones that also give you energy when you clear them do not. The length of time bushes take to regenerate varies; there are two varieties that take 24 hours, but most take longer.
To learn more about where bushes regenerate, see the article Do Resources Regenerate on Home Island?. Here’s a hint: the ones that give you extras like caoutchouc or a spike are usually found on Archipelago Islands.
The main advice here is to clear as many bushes as you can on as many islands as you can to get as many extra goodies as possible.
To learn more about where you can find bushes that will give you extra goodies when you clear them, check out the Archipelago Islands section.