Best free resources for CATS prep in 2026 — compiled list

The official candidate guide is something a lot of people skip but it literally tells you the topic weighting and domain breakdown. It's the roadmap for your study plan. Never skip it.

For CATS - Certified Arborist Tree Service of Albuquerque specifically, I found the PracticeTestGeeks explanations were detailed enough that I didn't need to buy a separate study guide. The combination of doing the practice questions + reading every explanation (for both right and wrong answers) covered most of the content I needed.

Great list. I'd add: LinkedIn Learning has some agriculture & environment-related courses that overlap with cert content, and if you have a library card many libraries give free access to it. Also check if your local library has access to O'Reilly or similar — tons of technical content there.

I work full time so studying for the CATS had to happen in the cracks of my day, and honestly that's the only way it got done. I'd do a few practice questions on PracticeTestGeeks during my lunch break and then a longer session after the kids went to bed. The explanations are what made it work for me because I didn't have time to go dig through a textbook every time I got something wrong. The risk assessment stuff was the part I kept failing so I drilled cats urban tree risk assessment mitigation over and over until it stuck.

My advice if you're busy like me is don't try to cram. Twenty minutes a day beats a four hour panic session on the weekend, trust me. It's free so there's no reason not to just start chipping away at it now.

Honestly the thing that helped me most was using the practice tests to figure out why my wrong answers were wrong. It's easy to just memorize the correct option and move on, but you don't actually learn anything that way. When I missed questions on the cats urban tree risk assessment mitigation section, I'd go back and ask myself what made the other choices wrong too, not just why the right one was right. That's where the real understanding clicked for me.

It takes longer, I won't lie. But on test day I wasn't second-guessing myself because I actually understood the reasoning behind each call. Read the explanations even when you get one right. Sometimes you guessed and didn't realize it, and those are the ones that'll bite you later.