So the bijuu are always sealed within a person, to utilize their power, or within an item. Either way they are contained. But what if you sealed a bijuu into the surrounding landscape?

In general the chakra of said bijuu should start getting pumped into flora and fauna promoting an evolution/mutation.

By extension the ppl of the land, should start to be affected as well. Stronger bodies, higher and more potent chakra levels. Possible emergence of new kekkei genkai, or the evolution of existing ones.

These are just positive posibilities I've thought of, which would require several key factors:

1. Specific bijuu being used and the land it's sealed to.

2. The amount of chakra being pumped into the land, as I fell it would need to be controlled/filtered somehow. Otherwise the land would one way or another become uninhabitable.

3. A sealmaster able to apply a seal that properly covers points 1 and 2. And honestly it would likely only be a Uzumaki that could do so.

Also few negatives:

1. Apart from even getting a bijuu sealed into the land (whether by force or agreement), said bijuu's temperment might play a role as well. The angry/crazed personality of Kurama/Shukaku would utterly devastate the surrounding land. Though again, a proper seal may be able to deal with that.

2. Pumping such powerful chakra into the land might start to have a senjutsu-like effect and be so potent it kills of anything that can't handle it.

3. Depending on the bijuu, the chakra natures of ppl in that land might start to change and match said bijuu, not to mention new children that start being born afterwards. So less nature affinity variety.

A sidenote:

I can't help but wonder if the temples the bijuu originally lived in might have served some similar purpose, pumping their chakra out into the surrounding lands, helping to sustain said lands, along with giving them somewhere to live and be safe.