Do seeds *need* inoculum?

I'm looking to plant some nitrogen fixing tree seeds in a giant, dead, overfarmed field. There are plenty of local N-fixing trees in my area that are nice enough to provide me the seeds for it, but none of them grow near this crappy plot. Can I just plant the seeds and let them figure out the N-fixing, or do I need to go buy some inoculum?

Aww, no answers?

The reason I ask is because I've read books that say when you plant N-fixing trees "Make sure you use X-BRAND inoculum!"

And I've read books that don't specify anything about planting N-fixing tree seeds besides just generic planting depth or soil type, etc.

But I've never read a book that says, "Hey, go ahead an plant this [N-fixing Tree] and don't worry about inoculum because [Scientific Nature Thing] will do it for you."

Welcome to Permies, Jay! I don't know the answer to your question but am confident someone will...sometimes it takes a while.
I do know that our black and honey locust pop up with nothing added and mimosa, redbud and wild indigo also, but then,
because these are in the wild, I don't know how many did not germinate.
I sometimes buy an inoculant for beans in the garden if it is new soil and they do better with it but after that one time it is unnecessary. It's hard to find out sometimes if something is really important or if we are just being sold something.

If you have the right kind of bacteria in your soil, you don't need to supply the inoculum.

With an annual crop like peas, this is really easy to test: grow the crop and check for root nodules at harvest time. If you find the nodules, then you have the rhizobium in your soil. If you don't, then no rhizobium and you need to inoculate if you want N-fixation.

With a permanent crop like trees, trial-and-error doesn't seem like an effective strategy... I'd probably just buy the inoculant and put it on the seeds.

Since you stated that there are plenty of those trees already growing in your region, here is a simple trick for you:

When you are collecting the seeds/pods, take a shovel full of soil from under the canopy also.
The soil should contain the inoculant that the seeds require for N-fixation.

John's advice is good. That's how I do it and know it works.

Oh, wow, the take soil from parent plant idea is so obvious and yet it never occurred to me! Okay, I'm going with that. Thanks for the excellent advice everyone!