Can you respond to your own landfall trigger by playing another land to create a second landfall trigger?

Landfall triggers are triggered abilities that go on the stack when you play a land. Once the trigger is on the stack, players receive priority and may cast spells or activate abilities in response. However, playing a land is not a spell or activated ability — it is a special action governed by CR 116.2a.

Special actions (CR 116.2) do not use the stack and cannot be taken while another player has priority or while spells and abilities are on the stack. You may only play a land during your main phase when the stack is empty and you have priority (CR 116.2a, 305.1). Since a landfall trigger on the stack means the stack is not empty, you cannot play a land at that moment.

Additionally, you are limited to one land play per turn by default (CR 305.2), unless a card effect grants you additional land plays. Even if you had additional land plays available, the timing restriction still applies — you must wait for the stack to be empty during your main phase.

Concrete example: You control Scute Swarm, which has a landfall trigger. You play a Forest; Scute Swarm's landfall trigger goes on the stack. You cannot now play a second land in response to 'create a second trigger' — the stack is not empty, so playing a land is illegal at this point. Your opponent may respond to the trigger, and after it resolves, if it's still your main phase and the stack is empty, you could play another land only if you have additional land plays remaining.

In short, landfall chains from a single turn's multiple land plays must be set up before triggers go on the stack, by having effects that grant extra land plays — not by responding to triggers mid-stack.