Hello, and thank you for reaching out to OSU Extension! 

Unfortunately, heavy clay soils are usually best for cow food. Forages tend to do better in these soils than food crops do. However, there are some options to utilize the ground you are on. Creating hills, or growing in raised beds can help you achieve success in producing food crops. 

In clay soils, adding Organic matter (like compost) and some forms of calcium (such as Gypsum) can help improve drainage. Still, ultimately the soil will remain a clay texture, and growing in it is rather difficult. 

Here are some resources if you are interested in giving it a go: 

Growing vegetables in Oregon: https://extension.oregonstate.edu/catalog/pub/ec-871-vegetable-gardening-oregon#prepare-soil

Clay texture in soils: https://extension.oregonstate.edu/news/diamonds-clay-soils-are-forever 

Fruit tree site considerations: https://extension.oregonstate.edu/gardening/berries-fruit/fruit-tree-site-considerations 

Thanks, 

Logan Bennett