are self-fertile. In some varieties, fruit yield could increased by utilizing pollinators. Most sweet cherries need a second variety for pollination, and even self-fertile varies have improved fruit-set with a second variety. Pie cherries can pollinate sweet cherries. Cherries do not need thinning. Figs Some figs produce fruit without pollination. Figs that are pollinated rely on fig wasps. Temperate nuts Almonds The blossoms of most California [Almond] varieties are self-incompatible, requiring cross-pollination with other varieties to produce a crop. The single most important factor determining a good yield is pollination during the bloom period. More than a million colonies of honey bees are placed in California Almond orchards at the beginning of the bloom period to pollinate the crop. California beekeepers alone cannot supply this critical need, which is why honey bees travel across the country to the San Joaqin Valley each year. Although the recommended number of hives per acre is 2 to 3, due to the high demand in conjunction with the reduced availability of commercial beehives, many almond growers have to make do with a lower hive density during pollination. These growers started using semiochemical formulations, like SPLAT Bloom, to compensate for the low hive density. SPLAT Bloom manipulates the behavior of the bees, inciting them to spend more time foraging, and thus pollinating flowers in the entire almond orchard (increasing pollination and fruit set), not only close to the hive. Research into self-fertile almonds has led to the development of several almond varieties that do not need a pollinator tree. Working from an old Spanish variety, "Tuono", researchers in 2008 started making available new self-fertile varieties that more closely match the qualities of the popular "Nonpareil" almond—including varieties "Lone Star" and "Independence". While self-fertile trees do not require pollen from a second tree variety for fruit / nut set, they still depend upon insect pollination for good production. Almond growers with self-fertile almonds report excellent nut set with half (or less) the number of bees in the field. Wind-pollinated nuts Hazelnuts (filberts), walnuts, pecans, and chestnuts are all wind-pollinated temperate-zone nuts. Mostly these wind-pollinated nuts are selected varieties that need two different varieties (and favorable winds) for cross-pollination. Insects and birds may visit and consume the pollen, but are not a factor in pollination. Edible seeds from wind-pollinated coniferous trees such as pine, ginkgo, and monkey-puzzle trees are also harvested and the seeds are colloquially called