Pine Trees

Pine trees very useful for survival situations.

To figure out if the needle tree you're looking at is a pine tree, you just need check how many needles come out of the same twig. If it's in groups of two, three, or five, then you've definitely got a pine tree.

In a survival situation, you should definitely constantly be chewing on pine needles. They're a source of vitamin C and will also provide slight hydration. That vitamin C will be crucial to avoid catching scurvy. Scurvy is potentially deadly disease that results from an extended period of Vitamin C deficiency, a relatively common disease for pirates back in the day. Symptoms will start showing up after around 4 weeks, including tired/sore limbs, bleeding from the skin, poor gums (leading to teeth loss), hair loss, and many more.

(Pine needle tea is also a thing)

It's just a really bad disease that can be easily prevented in most scenarios.

Last but not least, you can basically eat any part of a pine tree except for its outer bark. Of course there are some parts that are more desirable such as the pine nuts. To extract them, just collect a pile of relatively fresh pine cones. To get the seed out, you can just tap the cone against a rock or just rip it apart layer by layer. The things that fall out should generally be the seed that you can then peel to obtain the nuts.