Mudra as a Meditative Aid?

I don’t think the Buddha is saying we should abandon the ecology, or burn down the forests! The sticks and branches mentioned are for the purpose of making a simile, people generally do not consider random objects in the physical environment as part of themselves. In the same way, the Buddha is saying that is how we should regard what is known as the 5 “khandas”. Translating that word is a bit tricky: bundle, aggregate, heap, etc…
The 5 are as follows:

  1. form/appearances/body
  2. feelings/sensations (pleasant, unpleasant, neither)
  3. perceptions/concepts
  4. activities (of the body, speech, and mind)
  5. consciousness/subjectivity

Usually, we cling to and grasp at these 5 as if they are ourself, as if they belong to us. The Buddha here is instructing us to let go of these (as opposed to grasping at them and holding onto them).

That is simply my intellectual understanding of that dhamma, to actually deeply understand and live that teaching is to be awakened, so as you said, a very profound teaching indeed.

Here is some discussion on discourse about these grasping khandas: