Which factor is primarily affected by the removal of leaves around grape clusters?

The removal of leaves around grape clusters primarily affects the exposure of the clusters to environmental elements. When leaves are pruned or removed, the grape clusters receive increased sunlight and airflow. This exposure is crucial for the ripening process, as adequate sunlight can enhance photosynthesis, which contributes to grape sweetness and development. Additionally, improved airflow reduces moisture on the fruit's surface, mitigating the risk of fungal diseases and ensuring a healthier crop. By ensuring that grape clusters are well-exposed, growers can optimize the quality and yield of the grapes during harvest, which is vital for producing high-quality wine.