Silica quartz sand can be a beneficial amendment for afforestation (planting trees in areas that have historically lacked trees) in several ways:

* **Improved Drainage:**  Silica sand particles are large and well-draining,  which can help prevent waterlogging around tree roots. This is especially important in areas with heavy clay soils that tend to retain too much water.

* **Aeration:** The spaces between sand particles allow for good air circulation in the soil, which is essential for healthy root growth.  Poor aeration can suffocate roots and hinder nutrient uptake.

* **Nutrient Availability:**  While silica sand itself doesn't contain many nutrients, it can help with the availability of certain nutrients already in the soil.  Sand particles can help break down clay particles, releasing bound nutrients into the soil for tree roots to access.

* **Reduced Soil Compaction:**  Sand helps loosen compacted soil, making it easier for tree roots to penetrate and grow. Compacted soil can restrict root growth and limit a tree's ability to access water and nutrients.