In their natural state few parts of conifers are highly usable, many of the plant parts are bitter, astringent and in some cases toxic if not properly handled. We only have some historic use of conifers purely for flavor and in those cases most of them are utilizing the bitterness, such as the use of juniper berries in gin or the use of spruce bark in spruce beer which is sweetened to compensate for the bitterness imparted into it.

All things that are toxic are because of the presence of a compound in them that is unsafe to eat. The majority of conifers are toxic because of the presence of cedral, which is named after the Cedars. Unfortunately few cedars are edible because of this presence of cedral. There exists some isolates, like cedarwood terpenes that avoids this issue by solely isolating out the cedral, which is also unsafe for some perfumery use.

Most conifer parts are high in tannins and other agents making them bitter, soapy and unpleasant to the palate. The amount of these elements can often out-compete the usefulness of the flavors of most conifers.

The most useful way I have found to use conifers is to rely on essential oils, isolates, or CO2 extracts. This is because many of the downsides can be overcome by steam distillation. For instance none of the bitter or astringent elements carry over to essential oils, making for a robust flavor without the difficulty of having to overcome those elements in the food prepared, for instance by adding additional sweetness. Essential oils can be difficult to work with because of their intensity and unusual characteristics.

Most kinds of conifers can have their woods and leaves burned to impart food with the smoke produced. This will result in a smokey flavor as well as some of the flavors of the essential oils.

Fresh conifer needles can be used to brew teas and impart flavor by using them to form steaming baskets for foods. Be careful to understand that the species being used is safe to eat, as this method will impart cedral if it is present. This is a unique case because the benefits of the high level of vitamin C in pine and spruce needles can only be gained by gently heating the leaves and extracting it in liquid, but without boiling.

dried needles, bark, and cones can be used as spices. I consider this an impractical because of the weak flavor and high bitterness outside of the use of dried juniper berries.

Pine nuts have obvious culinary use, I hope to soon compile a list of all of the species of conifers that specifically make edible nuts, as some are toxic and a few others are unpalatable.