Helicopter seed collection from natural stands has been going on since the 1970s using cone harvesters.
Suggestions for faster collections
Cone collecting is fastest where trees have fairly narrow crowns,
tops have a heavy cone crop, cones are of good quality, cones are
not opening (so every tree can be picked), and most trees in a
patch have good crops. The biggest hindrance to a good cone
yield is cones that are turning brown and therefore unusable.
-A good pilot experienced with external load flying is the key to
getting cones to the ground quickly.
-Before starting a collection, locate key stands of heavy cone crop,
check seed counts, determine the maturity of the cones and find
suitable unloading and refuelling sites. This preplanning results
in a smoother operation and higher production per hour.
!
-Select unloading sites below the stand being raked because flying
upward with the basket empty is easier than with it full.
-Whenever possible, transport a rake to the collecting site by truck
or trailer. Aerial ferrying of rakes reduces helicopter airspeed to
about 80-90 mph (130-145 km/h).
-Fly paths that minimize distances between trees. Generally, fly
out empty and rake trees on the way back so that the longest
flight is with an empty basket.
-A ground crew of two is best but one person can clean a rake.
-Self-dumping rakes can dump tops directly into trucks or trailers
for transport to better sacking sites.
Generally, dumping sites should be less than two kilometres from
trees, although the species and abundance of cones influence the
cost/benefit ratio.
The supply of Fandrich aerial rakes has never been a problem. Even
during the heavy cone crop year of 1993 when all 49 Fandrich cone
rakes were working, every request for a machine was met on time.
Reserving a rake is part of a good collection plan.
Availability of helicopters can be a problem, though. During hot dry
summers helicopter companies may need to give priority to fighting
forest fires and may not have a machine available for picking cones.
Material and information from
http://www.coneharvesters.com/ please contact them for more information.
And for autonomous aerial tree seed collection the Chang Mai University in Thailand is working on this >
Youtube video link to their amazing work here