Pruning provides light within the tree, and bees will fly in areas where flowers are more shaded, if the tree is pruned. Pollen from trees short of nitrogen is markedly inferior in its ability to bring about fertilization, to pollen from a tree with adequate levels of nitrogen. Trees that are deficient in nitrogen often flower profusely, but the blossom is weak and fruit set is usually light. As temperature falls to 28 degrees F., ice formation within the flower tissue can cause injury to fruit finish. At 27 degrees and below, the styles and ovules can be killed, preventing fertilization.
Wind plays no significant role in cross pollinating tree fruit.
However, it does have an adverse effect in insect activity, that provides for cross-pollination. Hot, dry weather, will reduce the stigma receptivity. When the stigma is receptive to pollen germination, it glistens with a sugary exudate. Once it starts to dry and turn brown, it is no longer receptive to pollination. Bee flight is reduced by rain, wind, and cool temperatures, therefore, pollination may fail even though all other factors are okay.