Some forests develop after farmland is abandoned. Grasses may be overtaken by pine trees, which are eventually replaced by hardwood trees. During this process, the soil also changes. Which change during this process is a form of chemical weathering?

A. Recycled organic matter from trees lowers soil pH.
B. Increased shade from the tree canopy lowers soil temperature.
C. Rocks broken apart by tree roots add texture to the soil.
D. Water intake by trees reduces soil water content.