Can I Compost Pine Needles?

Yes - you can - but there are some ways that work best.
There is a lot of information about this subject online as this question is very popular with many homeowners.
I think one of the main reasons some people do not put it in a compost bin is that it is slow to decompose.
There are many suggestions shown such as running over the needles with your lawn mower to break them down into smaller pieces that will help the decomposing process. You also have to be sure you layer it with what is called 'green' hot materials to help the process.

If you are not familiar with keeping/using a compost bin it may be a good idea to read a few articles or ask your local Extension Service this question as they can tell you exactly how to do this for where you live and what type of pine needles you have.

helpmecompost.com/.../
www.growertoday.com/.../

ask.extension.org/ask

There are hundreds of studies about pine needles decomposition for a simple reason : There are more than 110 species of pines worldwide, and pine is the major tree of the Northern Hemisphere.

They produce litter all year round in big quantity, the decomposition of their needles is slow and not much influenced by climate, which means that many countries of the northern hemisphere are facing the same problem : large quantity of pine needles decomposing very slowly into a product of no interest as very poor in nutrients. It also means large surfaces of forests where very few other plants manage to grow because of the constant shadow created by pine trees, the dryness of the soil created by the thick mats of their needles on which rain waters only slide away. All this creating the ideal conditions for real disasters in case of fires.
To me the answer to your question is in fact : What for ? if you manage the decomposition of pine needles in your compost it will not give you a good rich soil to use to feed your plants. It will take a lot of your time because you will have to wait for the end of the 3 to 4 months period during which the decomposition of the needles acidifies the compost and makes it bearable only to plants that like acidic soil. On top of having to wait 4 months you will also have to take time to :
. put only little quantities of needles at a time and mix them well with others trees or vegetables leaves because the pine needles alone do not create the chemicals necessary to its decomposition,
. turn the compost regularly to aerate it for the needles not to stick together creating a mat that can nest and protect fungi which are not all harmless to plants. Watering the compost will not help nor speed up the decomposition of the needles as dry pine needles are nearly waterproof (that is one of the reasons why pines needles decomposition is not much influenced by climate)

Why all these worries for a compost that will not, in the end, be richer if not worse ?

I would use pine needles for what they are good for : in a thick layer round a plant to protect it against snails and slugs, in an alley to walk on them because it is nice to walk on them, and as mulch in a place where you do not want any plant to grow. In my opinion that is enough for gardening to stay a nice and fruitful leisure.

Hope this helps !

Catherine