It would probably be something I need to look at in person to assess exactly what is going in but generally speaking its not a really complicated formula......you need to maximize the amount of sunlight you can get to the ground.......you need a little light soil disturbance to help stimulate the seed bank and reduce residue buildup......and you need good soil management practices long term that builds OM when setting back succsssion........Take a shovel and go out and dig a soil pit and see what you see.....Is there a dark layer of soil on top of the ground? How thick is it? Send a sample in and have the soil organic matter % tested.......

If it were me in this situation trying to manage with cattle I'd set the woody gum back through chemicals application probably or fire......thin the overstory.....run cattle through it during late winter or early spring to stimulate the soil and deposit seed and manure.....then I'd let it go and see what I had with the intention of rotation the cattle back through later on for another round of the same....more plant diversity should begin to arise....I would probably intentionally pull them from a vibrant diverse stand and run them through your biological desert in order to help bring in some seed. The manure also acts as an inoculant for microbial life...If the understory was really barren it might be a good idea to set out a few round bales of hay for the cattle to help supplement their diet and provide another seed source to deposit in their manure.....Also those areas where the hay bales sit are definitely gonna spring forth with plant growth that might help inoculate the area with seed as well....I believe they call those loafing areas maybe