Learn Spanish (Latin America): Recién corté el tronco con la sierra.

In Latin America, using recién immediately before a conjugated verb in the preterite tense (like corté) is a very common way to say you 'just' did something. While acabo de cortar is universally understood, recién corté gives you that natural, everyday Latin American flavor for immediate past actions.

Could I put recién at the end of the sentence instead?

When using recién to mean 'just', it almost always goes directly before the conjugated verb. You might occasionally hear it at the very end of a phrase in spoken Spanish for emphasis, but placing it right before corté is the standard, expected structure for this pattern.

Does tronco mean both 'trunk' and 'log'?

Exactly. Tronco is the main trunk of a living tree, but once it is felled and cut into thick sections, those pieces are also called troncos (logs).

Is the word sierra related to the word for a mountain range?

Yes! The primary meaning of sierra is a saw (the tool). Mountain ranges are called sierras because their jagged, up-and-down peaks literally resemble the sharp teeth of a saw.