I heard that trees come in male or female, makes sense I guess, but how do you tell what "sex" you are getting and do both trees produce seeds? Thanks!

Depends on the type of tree we are talking about.

In general terms (very general) the flower is the gender based part of the tree. Many trees produce both male and female flowers – not all of them, some are decidedly male or female and require a partnership to make fruit.

In general terms male trees produce more pollen, have smaller flowers and smaller fruit. On a single tree with male and female flowers, a whole branch can be devoted to a gender – usually the differences between male flowers and female flowers requires serious study of the flower – in some cases you can just see the pollen dripping out of the male flowers (Yes seriously it happens – no joke)

For some evergreens the location of the seed in the cone determines male or female.

Most (not all) of both genders produce viable seed in most species of tree.

Here are some specifics on a few species:

Trees Pecans have separate male and female flowers on the same tree. (Self Fruitful – unless the male flowers come in earlier than the female flowers - If the male pollen is shed before the female flower is receptive, fruit-set becomes a problem).

Pistachios have male trees that produce pollen and female trees that produce fruit. To grow them successfully, it is necessary to plant at least one male tree for every eight female pistachio trees.

Most apple trees are self unfruitful. 'Golden Delicious', a self fruitful variety, and 'Jonathan' are the most common pollinators used. Again even with in a species there is the exception with Golden Delicious being self fruitful.

Sago Palms (decided male and female): The male Sago palm sprouts a long, um, tubular erect cone-line structure from the top of its crown. The female has a round, um, receptacle thingy where pollen collects – it’s sort of like, well, female. – at the top of its crown with sort-of-kind-of egg shaped things inside a protective (but easy to open) envelope.

No I’m not making this up: http://aggie-horticulture.tamu.edu/galveston/sago%20palm.htm

Self fruitful is a different way to say bi-sexual I suppose

"Self fruitful is a different way to say bi-sexual I suppose" More like hermaphroditic, I think.

Interesting discussion. But I thought most commercial fruit trees were propagated vegetatively with cuttings (clones)?

Thanks David...the reason I was asking is because we have several maple trees in our yard and one produces a ton of those helicopter seeds, the others a moderate amount and the one produces none or very little.

quote:

Originally posted by Professor:
"Self fruitful is a different way to say bi-sexual I suppose" More like hermaphroditic, I think.

Interesting discussion. But I thought most commercial fruit trees were propagated vegetatively with cuttings (clones)?

Quite correct - however fruit bearing (size) in some like the pistachio depends on there still being male and female - don't matter if they are clones or natural.

quote:

Originally posted by kittypal:
Thanks David...the reason I was asking is because we have several maple trees in our yard and one produces a ton of those helicopter seeds, the others a moderate amount and the one produces none or very little.

Well I found this for Silver Maple:

"Four types of trees, with respect to sex expression, have been observed: all male flowers; all female flowers but with rudimentary pistils; mostly male with a few females; and mostly male with a few females and a scattering of hermaphroditic flowers (19).

Silver maples growing in Holland showed a tendency for the same tree to produce female flowers one year and both female and male flowers the next year. Trees that produced all male flowers did not show this type of change (6)."

http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/acer/saccharinum.htm

It is possible that you have a female (the seed producer) a male (non seed producer) and the two gender ones (I still say bi-sexual - I can't spell let alone say hermaphroditic)

I do not know if this applies to all kinds of maple (ex: Sugar, Red, Japanese, Norway.... etc)

Thanks again David, I KNEW you'd know the answer to my question!!!