Tomato trees not producing fruit.?

We have four tomato trees, about 3 foot tall each. They are growing very healthily, but they are not producing any fruit. What can I do to them to produce fruit?
Update: Ok, so technically it isn't a tree, but it's the plant that tomatoes grow out of. I've had tomatoes grow when I lived in Korea and this is the exact same plant. How do I pollinate them with a q-tip? We live in Alaska now and the "trees" get plenty of sunshine, over 16 hours everyday.... show more Ok, so technically it isn't a tree, but it's the plant that tomatoes grow out of. I've had tomatoes grow when I lived in Korea and this is the exact same plant. How do I pollinate them with a q-tip?

We live in Alaska now and the "trees" get plenty of sunshine, over 16 hours everyday. I'll trim some of the leaves today, see the results.
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