I have lots of tall pines on my urban residential plot. it is sizeable. I deal with lots of pine needles annually. I deal with lots of pine needles all the time! I have been gardening
with complete success there in for over 30 + years encircled by tall pines on the 180-degree line, in line with the sun... I am in growing zone 9a. summer and winter suns do matter, but not that much as dif seasons call for dif crops. generally, summer fruits, fall roots.
first and foremost, consider sun, sun and more sun... as your most important garden location consideration. all else can be rectified. if the tall pines will only drop
some... needles on ur plot then from my experience then that will not be a problem. mine drop a lot all over my plot. it is a never ending constant issue. worst in fall and feb, eases up some in summer. raking needles is kin to mowing the lawn... lol. from experience I have found the off shoot roots of pines will flow out deeper than only 12". pine needles will, if in excess... influence, as stated your soil's ph... but over the years... I really have not worried about it. and I don't fuss too much about it. I concentrate more on soil quality, friability and such. I have a significant compost program on-going, too. no shortage of good info on how to lower it online. a good start is a good ample compost program. can be as simple as just a pile or welded wire circles. I do not turn any of my compost. [too much work! lol]... I have tons of rich, beautiful forest floor like compost. so sweet is it, sometimes I just grab a double handful hold it up and savor the freshness!!! compost - good stuff.
I would encourage you to go for the best location with the best sun, given ur description of your plot area you are considering. get a good tiller and till up the plot to start with. assuming it has never been tilled, it will not be a till once plant and go. every time I till I always hit a root or two. pine tree roots, imo... no big deal at all! just deal with it. and it's easy to do. too big, I stop... and get down on it and sawsall it out... put back soil over it and carry on. 3/8ths to 1/2" diam roots may be common. yet, still never a real issue. but doubt they will be prevalent. not from my experience. you may want to start of with a small garden plot first year... a lot can be grown as such. then work out to larger plot
as u learn more about your land, pines, their effects, etc. I use the needles in my compost, for mulch, weed control... etc. good soil, some tilled in pine needles, and good compost will make a nice friable soil. volumes could be written, shared to help you with your question... gardening is a vast, complex interesting activity. been with us as a species for almost forever. hunter/gathers. the latter is the gardening. (simplified) no two years will ever be the same, despite same plantings, and some stuff just wont do well in some growing zones. no two garden plots are the same, either. you didn't state ur location so hard to know ur growing zone. but every season will be a new learning experience no matter how many years you garden.
the other posts here are no doubt from gardeners, too. experienced. but unless they have indepth gardening experience under, with and along big looming pine trees... they can only offer help in generalities...
be cautious of buying too much this or that at the big box stores or even local feed-n-seed centers. really easy to spend $30-40 per trip... just remember... that buys a whole lot of fresh vegetables at your grocery store. I don't buy at any farmer's markets. you don't want to be showing off your nice newly ripened tomatoes... that cost you $10.00 each! lol... learn learn study and learn...
start small. go for sun, sun, sun! learn your land and plot. till it well. don't get too concerned about tilling deep initially, more so make raised beds. start small, think big!!
make raised beds. be optimistic... and have fun. and if you do not have a copy, get ahold of D-ick Raymond's book:
The Joy of Gardening. he was very involved with Garden-Way and Troy Bilt Tillers before MTD. fabulous story of those companies... I can tell you this much... once I got a Troy Bilt tiller and read D-ick's book... I never looked back. and I never had a need to buy another book on gardening. I garden according to the methods and techniques in his book.. has worked for me flawlessly for over 30 years! my garden is the talk of my neighborhood!
it is a wonderful read and you will not regret getting a copy. its all about gardening strategy, methods, techniques, ideas, and on and on... and just full of tons of beautiful full color pix, too... D-ick is a master gardener of master gardeners!...
http://www.amazon.com/Garden-Ways-Gardening-****-Raymond/dp/0882663194
also: google The Bayou Gardener. many many vids on gardening. his vids are awesome!! his gardens even more so.
good luck and best wishes for many fun gardening seasons ahead...
pix memo: need I say more?
:
no shortage of big pines at my place, they encircle me, garden to L of garage...on S side.