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 and needles 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. When it comes to conifers the most important toxins to discuses are taxine alkaloids, these are found in all species of yew. I do not advise eating any part of any species of yew.

Another compound to discuss is thujone, which is toxic but also found in a number of common spices, such as sage, wormwood, and oregano. It is also found in cedars, junipers, and cypresses. Thujone has a strong minty, rank and slightly caraway like scent. It is considered toxic to the liver and kidneys and in large quantities causes convulsions and eventually death. It is considered safe and a mood elevator in small quantities. In the United States, food needs to have below 10 mg/l of thujone to be considered safe. This translates to about 2 drops of pure liquid thujone per liter of liquid. This amount is far more then enough to strongly flavor the liquid. While many conifers have thujone, The amount used to impart flavor to a dish is well within the safety limits. For an acute overdose a huge amount of plant material would need to be eaten. Long term continuous use of amounts above the recommended 10 mg/l of thujone is harmful to the liver and kidneys. The main concern about thujone is avoiding consuming it everyday, and in amounts that would strongly flavor a dish. Many spices can be safely used that have thujone, just with consideration of the frequency and amount used. I will be listing any conifers that are known to have thujone in the edibility section below.

Previously listed here was cedrol, which causes skin sensitization, but is not in fact toxic to consume. ¹⁾ Cedrol is named after cedar, is photo toxic and sensitizing, it is regulated and limited in its use in some essential oils. There exists some isolates, like cedarwood terpenes that avoids this issue by solely isolating out the cedrol, which unsafe for some perfumery use, and as a consequence offers the flavor profile of a cedar without the cedrol present.

Isocupressic Acid has been shown to induce abortions during the first trimester of pregnancy in cattle. This exotic wood acid is present in 4 species of pine, the Ponderosa pine (Pinus ponderosa), Lodgepole pine (Pinus contorta), the Jeffrey pine (Pinus jeffreyi), and possibly in the Monterey pine (Pinus radiata). There have been no connections made with the effects this has on humans, but there has also been little overall research done on the acid in general. ²⁾ Consuming any of these species while pregnant is not recommended.

Most conifer parts are high in tannins, exotic acids, and other agents making them bitter, soapy, and unpleasant to the palate. These unpalatable elements can often be much stronger then the desirable flavors in many conifers. Additionally man part of a conifer have unpalatable textures such as the bark, wood, cones, and older needles.

Conifers can also contain exotic acids such as abietic acid and plicatic acid which taste astringent and unpleasant.

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 the bitterness in prepared foods, typically by adding additional sweetness. Essential oils can be difficult to work with because of the small quantities required, and the difficulty of proper storage. Often only one drop of essential oil is enough to flavor a large pot of food. Because of this I recommend mixing essential oils with high strength alcohol to make them easier to use. Essential oils also need to be stored in a tight closing glass container with a lid made of a specific plastic that is not porous enough for the essential oils to leach through. Luckily essential oils are usually sold in suitable storage containers.

A simple starting recipe is to take a small bottle with a dropper and put in 1 part essential oil to 10 parts alcohol, preferably 95% alcohol, something like everclear. This mixture can then be used to add the flavors much like how vanilla extract is used to impart vanilla flavor. Each species has a different composition to its essential oil, and will have a different intensity once mixed, and the ratio of alcohol to essential oil can be adjusted. Once this mixture is made it can be used one drop at a time, allowing for far more precise use of the flavor then using the essential oil directly allows.

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 all compounds present. Additionally many conifers have high levels of vitamin C, notably pine and spruce needles, and this can only be extracted by gently heating the leaves and extracting it in water, but only below boiling temperatures.

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 specifically 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.

Below I will list conifers that are generally edible and which parts of them are commonly used. This list will have some complications as different conifers have different aspects of usability.

As far as I understand no species of Araucana have edible foliage or bark ³⁾, but the nuts of many are often considered prime. The foliage of Araucanas does not have any notable scent and is unlikely to have distinct flavor. There is some evidence that Araucaria bark also contains isocupressic acid. ⁴⁾.

As far as I know all Thuja cedars, and all parts contain thujone.
the inner bark of Thuja plicata and occidentalis is edible ⁵⁾
It would appear that the young cones and needles of Thuja are edible as well.

Thuja occidentalis has edible cones ^{6) 7)}
Thuja plicata

I can find relatively little information about the edibility of old world cedars (genus Cedrus). There are 4 species in total, and It appears the essential oils from these species is edible, but there is little information online of any parts that are commonly eaten.

All species in the genus Abies are edible

So far I have only confirmed that the berries of Junipers are edible. Juniper leaves and bark contain Thujone

Juniperus comminus- This is the most commonly eaten juniper, its leaves and cones (berries) are widely used.

All species of Pinus are edible to some degree.

Pinus mugo- All parts are edible, with young needles and cones being palatable. Cones are commonly preserved in sugar syrup and able to be eaten directly. ⁸⁾
Pinus koraiensis- Korean Pine, has edible nuts considered to be choice.
Pinus pinea- Italian stone pine , has edible nuts considered to be choice. This species also has a very pleasant tasting essential oil.
Pinus edulis- Pinyon pine, this species has nuts considered to be choice, Ths species produces an essential oil that is superb.

All species and all parts in the genus Picea are edible. Spruces are historically used to cure scurvy and are the main flavoring agent in spruce beer.

All parts of every species in the genus Taxus are highly poisonous and toxic to eat. This is due to the presence of taxine alkaloids, a whole class of toxic alkaloids which are present in varying amounts in yews. There are some accounts that the fleshy red cones (but not the seeds) are edible in the species Taxus baccata, but I did not find sufficient evidence to support claiming they are edible. I would avoid eating the cones and any other part of any species of yew unless more convincing evidence is presented.

All parts of plants in the genus Podocarpus, often called yews, are also toxic. The fleshy cones on some species is also reported as edible, but again, lack sufficient evidence to be recommended.

Abstract on the effect of breathing conifer dust ⁹⁾