The biggest issue I have had growing edibles under pines is the lack of water.
I've been trying a small forest garden under some white pines for the past two years. The pines seem to deflect most light rains away from the forest floor. These pines were planted 30 years ago with a row of oak trees in front (south) of them. Because of the oaks, these pines grew very tall with few lower branches. Just in the last three years, we had to remove the oaks which has drastically opened up this pine forest. The problem is there does not seem to be much of any pine needle coverage on the forest floor, making it very dry this summer.
I started with haskaps (Lonicera caerulea) last year and got a good harvest the following spring, tho the berries are quite tart. Also planted ostrich ferns, hardy kiwi (just south of the pine forest for better sun), and blueberries (also south) last season. The kiwis look good but the ferns, haskap, and blueberries are suffering because of too little water. It seems as tho this forest could use a light layer of mulch until the pines can better cover the soil. This season I added a salal (Gaultheria shallon), sorrel, grape, smooth sumac, mulberry, and claytonia. Again, the lack of water is stressing them, in fact all of the claytonia has died. Just recently, I noticed some type of physalis and several small pawpaw trees growing wild in this pine forest so i may try more of them. Plans for next year include better ground coverage to hold the water in and more pawpaw trees deeper in the pine forest.
The idea to put a yucca under the pine trees sounds good but I'm out of space where it could get decent sun. Also, someone mentioned gooseberries; my understanding is they can harbor white pine blister rust, so they should not be planted anywhere near pines. Anyway, back to the topic:
Edibles under pine trees:
Pawpaw: Growing natively
Physalis: Growing natively
Kiwi: Need decent sun for a good crop (According to other growers)
Haskap
Osterich Ferns
Blueberries: Need decent sun for a good crop (According to other growers)
Salal
Sorrel
Grapes: Need decent sun for a good crop (According to other growers)
Sumac: Need decent sun for a good crop (I have seen this)
Akebia
Comfrey
Mulberry
Udo
Wintergreen
Yucca
