The problem is that in many countries, this logging is done at a much faster rate than the trees regrow. Cattle ranching . Cattle can have up to six to ten years of grazing, after which a scrub savannah grows up. The heartwood is durable, and changes from yellow to streaked chestnut tones during seasoning. The rubber latex is collected from trees that are tapped in a sustainable process.
Natural rubber is superior in resilience to synthetics.
Monoecious plants with unisexual flowers that typically do not have sepals or petals. Most spurges have milky, often toxic sap. The seedcoat of the seeds is hard and stony, as you've learned with your nutcracker. Almost all of the world's supply comes from harvesting wild plants. Sustainable harvests would be local enterprises.