I have 2 massive deodor cedars in my yard (70+ feet high), a male and female. Once a year the male drops all of it's pollen in a very short time. If my dog is napping on the driveway and then gets up you can see the exact outline of where the dog was! The pollen effectively covers about 1/2 an acre in yellow. My question is, how does it decide when to do this? I have tracked the date for the past 6 years and it varies from October 5 to Nov 1, but I can't see any pattern except that it was very wet here for the past few days and now we are supposed to have a dry spell for 2 or 3 days, and it only pollenates when the weather is dry. Is there a temperature or moisture correlation? length of daylight hours ? or is there a communication link between the 2 trees and he is waiting for her seeds to drop first? or does his pollen need to land on her seeds before they drop (I rarely see her pine cones)? I'm just curious about these 2 trees and want to understand them better. -Meryl
Pollen shedding is most likely controlled by dry weather allowing the pollen cones to dry out and open enough for the pollen to blow out. Temperature through the summer may have an effect too, in determining when the pollen is mature - I'd expect earlier shedding after a hot summer. The paucity of cones on the other tree may well be because the two trees are not in synchronisation. If there were more cedars nearby providing a longer period of pollen shedding variation, you'd probably get more cones. The seed cones take one year to mature after pollination. Note that cedars are not fully single-sex; you may also get some seed cones on the 'male' tree and pollen cones on the 'female' tree. Oh, and you won't ever get pine cones on a cedar, only cedar cones . . . pine cones on a cedar is like a cat having puppies ;-)
Very interesting- we had a lot of cold weather the last half of October, so it may have taken a bit longer for the pollen to mature. I've been looking around the area, and don't see any other cedars in the vicinity, at least not like these trees. I had no idea they were not fully one sex- only one of the trees produces pollen as far as I can tell- but in copious quantities!. And now I know to look for the cedar cones especially if they can be seen on both trees. Thank you for the cat analogy- our goose once hatched a duck egg. The duck thought it was a goose and the goose was confused by it's offspring's behavior and food choices. Not quite like a cat having puppies, but an interesting biology experiment. My next dilemma is how to determine whether we have Deodor or Cedars of Lebanon. The needles are too small for me to see whether they are square in cross-section. Is there another way?
Couple of tips - Deodar Cedar needles are roughly twice as long as Lebanon Cedar, 3-5cm versus 1.5-3cm; and Deodar Cedar cones (seed cones) break up fairly promptly after ripening in autumn or early winter, whereas Lebanon Cedar cones don't break up until late in the winter (and often persist looking rather shabby through the next summer as well).
