Lava Rock vs. Wood Mulch for Pine Trees: Removing Plastic Barrier

Lava Rock Is Inert—But the Plastic Isn't

Lava rock itself doesn't harm pines. However, the landscape fabric underneath restricts gas exchange, traps heat, and causes roots to circle and suffocate. Remove every piece of plastic.

Transitioning to Wood Mulch

1. Rake off all lava rock (save for reuse elsewhere).
2. Pull up the plastic completely.
3. Apply a 3–4 inch layer of compost or aged bark mulch.
4. Monitor for nitrogen deficiency (yellowing needles) as fresh wood chips decompose; apply a light nitrogen fertilizer if needed.

Why Compost Over Chips

Compost feeds the soil immediately; chips tie up nitrogen. If you prefer the look of chips, use aged, partially decomposed material and supplement with fertilizer.