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  1. #1
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    Default Wind pollination...

    I'm compiling a complete list of bee-friendly trees for our area, and I started to wonder about the other trees... What about the oaks, the birches, the hornbeams and the hophornbeams, etc.?

    Finally it dawned on me — wind pollination!

    Now I'm wondering, why doesn't the wind get mentioned more often? (The wind is invisible!) I don't see it mentioned in the various articles on the web that have lists of trees that are good for bees (and other pollinating insects). I haven't yet found a database/directory that consistently tells you which tree species need insects for pollination, and which can do without (looking at the USDA plants database and the Native Plant database, among others). I can find only a few threads in Beesource (1, 2, 3, 4, 5, 6) that mention the 'wind' as a factor. But it does seem to be the single, overall, most determining factor in the question of which trees are not good for bees.

    Help! Is there any place (books, online, whatever) that can help to explore this question? Any resident experts?

    In Britain you have to study for years to be a certified beekeeper. Is this part of the course? at what level?

    Here's the best discussion I've found thus far, an article in a relatively obscure magazine called Northern Woodlands. Totally unrelated to beekeeping. And perhaps the bee journals have had articles. Any specific citations?

    Wind-pollinated trees sometimes get cited in Beesource as bee-friendly. I understand why (the bees get pollen), but what's up with that? Trees that wind-pollinate generally keep the male flowers (sometimes called catkins) separate from the female flowers. I'm guessing (obviously some people have figured this out already) it's to improve the odds of cross-fertilization between different trees, rather than one tree always pollinating itself. If the bees aren't helping to pollinate as they make their rounds, what's in it for the trees, or are the bees just free-loading on the surplus pollen?

    I could suggest other examples for discussion here (Hazelnuts/Almonds, Honey Locust, Birches, Elms, etc. can be taken one by one). But first I want to ask, why isn't this question (wind-pollinated, or not?) mentioned in beekeeping circles?

    (If it is, once in awhile, I probably missed it with all the fuss about varroa mites, chemicals, etc.)
    Last edited by Kofu; 10-31-2015 at 02:17 PM. Reason: added some links
    Beekeeping - a form of magic that weaves together two elements: wood and bees.

  2. #2
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    Default Re: Wind pollination...

    Well, there isn't just bees and wind, there are other things that pollinate.

    There are lots of good bee-plants that are dioecious meaning that there are separate male and female plants for the species. Stag-horn sumac is one.

    I'm not sure what your question is. Some plants are useful to bees, some more than others, and some not useful, all the time. Wind pollination is just another way that some plants reproduce; it has no relevance to bees. Pollination is not the main point of honeybees. Plants, in general, would get along fine without honeybees. However, food crop plants that humans depend on would suffer without honeybees.

    Enj.

  3. #3
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    Default Re: Wind pollination...

    I am not sure what your question is.

    California Coast Live Oak (Quercus agrifolia) is one of the earliest pollens in my region. The appearance of the catkins marks the beginning of "spring" for my colonies.
    Attached pix is from 12/14/2014 --- so you get an idea just how early a spring these oaks provide for the bees. My bees make honeydew honey from the honeydew of oaks, but only in the hungry fall season. Nozevit is reported to contain tannins from Oaks -- and the compound quercetin, a flavonol that initiates immune gene expression in bees, is named after the genus for oaks, from which it was originally isolated.

    Bee on Live Oak.jpg

    Many wind pollinated trees and crops are worked by bees -- the protein and fat content of the pollen appears to be a distinguishing characteristic for the pollens that are sought after. My bees do not gather the local pine and cypress pollen, and these, as a class, are very low protein.

    My local Willow trees are wind pollinated, but they are relished by bees, and the trees have "extra floral" nectaries -- pits on the leaf and stem petioles that dispense very concentrated sugars --- my bees will actually store surplus off the willow pits.

    Red Alder marks the beginning of spring flow in the Pacific Northwest. This is a catkin and "cone" tree.

    If I were to make an evolutionary speculation -- I see trees of the savanna landscape (live oaks) and narrow linear stream corridors (willows, alder, maple) as favoring honey bee assistance. In other words, trees with dispersed distribution will favor bee pollination, as the travel distance of the bees working the catkins transfers the pollen farther and more effectively than the wind alone. The assistance of the bees in locating the dispersed trees is rewarded with a nutritious (protein and fats) pollen. Bee pollinated trees arguably have a more diverse and resilient genome than non-bee assisted trees. Pines have very low diversity within a species, and oaks have high gene flow. Unstable environments (Mediterranean coasts) versus stable Boreal Forest would favor gene flow over conservative strategies.

  4. #4
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    Default Re: Wind pollination...

    Quote Originally Posted by enjambres View Post
    Some plants are useful to bees, some more than others, and some not useful, all the time. Wind pollination is just another way that some plants reproduce; it has no relevance to bees. Pollination is not the main point of honeybees. Plants, in general, would get along fine without honeybees.
    I'm feeling my way along, here. I have mostly questions and I appreciate your help in clarifying them. Thanks for the example of stag-horn sumac. Do the male flowers produce pollen and the female flowers nectar? Otherwise, why would bees fly to flowers on both male and female trees? (I could look it up [*] but the questions illustrate my path of inquiry.)

    I see the relationship between flying insect pollinators and some species of plants as symbiotic. I'm not focused on honey bees in particular, with my questions, and with that said I'm pretty sure that many species of plants would die out pretty quickly without bees, butterflies, flies, and other flying insects.

    For me, the questions became important as I started sorting a specific set of trees (approved for planting along the streets in Philadelphia) between bee-friendly trees, and not so bee-friendly.
    Last edited by Kofu; 11-01-2015 at 08:09 AM. Reason: link

  5. #5
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    Default Re: Wind pollination...

    Quote Originally Posted by JWChesnut View Post
    I am not sure what your question is.
    In a practical sense my question is, why wasn't I able to find this sort of information before, when I searched Beesource for it? And why didn't I stumble upon it sooner when I searched the web and read lots of pages about what sorts of plants are good for "the bees"?

    Obviously, that reflects my ignorance and the limits on web-search and time for reading what turned up, but I've been at it for a couple of weeks. When I got to a plateau in my understanding, I turned to Beesource, knowing that I can find people here who know a lot more than me and are willing to entertain these questions. And I'm serious about that. Thanks for the detail in your response. I feel like there's more climbing to do now, in order to get to a higher level. I'm not in a hurry. Thanks for your patience.

  6. #6
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    Default Re: Wind pollination...

    Part of my understanding comes from realizing that honeybees are opportunistic foragers, moochers who take advantage of pre-existing relationships between certain plant species and certain insect species. So we're not looking at the honeybee species as the canary in the mine. They'll get by with just about anything, comparatively. With beekeepers in the mix and hives on the move, they diligently serve to pollinate lots of different crops bred from plants that perhaps once had more specific relationships with certain insects.

    Here's a good article that I read awhile ago, which toward the bottom develops the idea that the broader web of relationships may be in jeopardy. There's a chart showing "the interaction network of flowering plants and pollinators in an Illinois forest fragment." Brandon Keim, "Beyond Honeybees: Now Wild Bees and Butterflies May Be in Trouble," in Wired magazine, May 6, 2014.

    Extrapolating from all that, as beekeepers we may still be interested in why certain plants are "friendlier" to bees. And why, for good reasons, other plants don't need to be particularly "friendly."

    I'm curious about the Willows that JWChestnut wrote about, which have "'extra floral' nectaries -- pits on the leaf and stem petioles that dispense very concentrated sugars." Why, if those trees are wind-pollinated? Is it in order to have a mix of local 'endogenous' mating (marrying within the tribe), and exogenous mating (adding genes from trees that otherwise would be out of reach, wind-wise)?

  7. #7
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    Default Re: Wind pollination...

    Oh, I see about the street trees question.

    In answer to your question about staghorn sumac. Bees work both sexes of plants, rather vigorously in most years here in my farm in upstate NY. But I think they do a more intense job on the male plants with the pollen. But that might simply be because there other blooming plants with better (more nutritious, richer, sweeter, more accessible - who knows what a bee thinks?) providing nectar at the same time, but the stag horn pollen is temporarily king of the pollen menu. This would vary from place to place as there might be different sets of co-blooming plants.

    A boring (non-native and over-planted to the point of banality), but bee-friendly street tree is the European linden. It is also highly tolerant of city conditions, hence its ubiquity. It provides excellent nectar and and some pollen but only for a short time (about two weeks, less if there is a heat wave). It blooms at a young age, too. Less than 15 years I would think. Not I think as bee-useful as its American cousin, the Basswood, but better scaled for urban life and a more reliable annual bloomer than Basswood.

    Bees adore tulip trees but they are too big for street trees; good for parks, though.

    All kinds of apples and pears are useful.

    But the primary issue is which trees will tolerate the awful, anti-tree conditions of an urban situation.

    A to find out that, there's a book you should get from your library: Michael Dirr's, Manual of Woody Landscape Plants. (It's expensive - $70 - so get your public library to get it for you.) He covers every single woody plant there is in all but the farthest south areas of the East. It's highly technical about the plants (trees, shrubs, even vines) - nothing about bees, as is it intended for horticultural audiences. But it's very readable and he is an articulate and opinionated, and often very funny, writer. He gives info on flowering, height, cultural demands, usefulness in parks, streets, etc. Info gleaned from it will impress the heck out of your co-workers in the street tree project.

    There are several libraries near to Philly with it in their collections and your local librarian will be able to get it through inter-library loan. They love to hunt down books like this for patrons.

    Once you've read about trees then there's a good (new) book on bees and cultivated plants from Wicwas press: Garden Plants for Honeybees by Peter Lindtner. It covers trees, too. It costs less ($34) but WorldCat doesn't show any listings for it close to you, but you could still ask for it. It has more popular appeal because it is specifically for beekeepers who want to enhance their environments for bees. Wicwas also has a new book out (which I have not seen, yet) called The Flower and the Bee, by John Lovell which I think might be useful to you. For both of last two look at www.wicwas.com.

    The Xerxes Society is dedicated to pollinators of all kinds and they have info on line as well.

    I can suggest many other good tree books, besides Dirr. (I am a professional horticulturist.) But Dirr is always my go to book. No pics though in that one. He has a couple of lovely glossy picture books, but you need more technical info.

    You will have lots of good options for trees in Philadelphia. It's warm enough so you can count on the lovely Mid-Atlantic range of trees, but still have northern ones, too. I know the climate well as I went to prep school in Bucks County.

    Don't forget that bees use trees for propolis, as well as for pollen and nectar. I think one is cottonwood. (Too big and messy for street trees, but often found in damp waste areas in a city. Think abandoned rail yards by the river, and fenced-off wetlands near malls and corporate parks.) But there are other sources, too.

    And of course, as yucky as it sounds, bees also gather a lot of "nectar" from insect honeydew. Primarily from aphids that are feeding on the leaves of trees. Honeydew is the sugary secretions (equivalent of poop) that the aphids produce. Bees gather it and bring to the hive kind of like half-baked honey. OK, I know you're thinking eeeeeuw, but that's the way it is. And street trees, under stress and because of social pressures not to spray often have an excellent crop of aphids. So a tree that wouldn't be a good nectary from its own flowers (say oaks) might still wind up being a source of honeydew to be made into actual honey by our favorite little buzzers.

    You probably won't be surprised to read that I am my bee club's librarian. The only thing I love more than my bees are bee books. (And books on plants which I have pored over since childhood.)

    Enj.

  8. #8
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    Default Re: Wind pollination...

    Quote Originally Posted by Kofu View Post
    I'm curious about the Willows that JWChestnut wrote about, which have "'extra floral' nectaries -- pits on the leaf and stem petioles that dispense very concentrated sugars." Why, if those trees are wind-pollinated?
    The function of EFN (extrafloral nectaries) on most plants (they are widespread) is to attract predators (primarily ants) that remove plant pests from the leaves. Some EFN are very highly evolved -- with toxic and fragrant compounds to attract particular insects. There is an enormous literature on the evolution of EFN relationships.

    Start here: http://www.extrafloralnectaries.org/

    This paper on EFN in willows should alert you to the complexity of this system (and has a good bibliography to boot)--
    http://www.esajournals.org/doi/abs/1...T%5D2.0.CO%3B2

  9. #9
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    Default Re: Wind pollination...

    Quote Originally Posted by enjambres View Post
    ... staghorn sumac ... European linden ... its American cousin, the Basswood ... tulip trees ... apples and pears ...

    But the primary issue is which trees will tolerate the awful, anti-tree conditions of an urban situation.
    Oh, the city environment's not so bad. There are stresses, of course. For trees planted between the sidewalk and the street definitely there are limitations. I think the main limit is on softwood trees (willows, cottonwoods, etc.) with limbs that are likely to break off and drop on cars or pedestrians. And trees that need the company of other trees, undergrowth, etc. are not going to do well along the street.

    For anyone interested, here's Philadelphia's actual list of "PPR Approved Street Trees" (pdf, 442k) linked from the Tree Philly FAQ page.

    Michael Dirr's Manual of Woody Landscape Plants ... very readable ... very funny ... info on flowering, height, cultural demands, usefulness in parks, streets, etc. ...
    Thanks for that title. I'll get hold of it. I had out Urban trees : a guide for selection, maintenance, and master planning, by Leonard E. Phillips, Jr. It's a little out of date (1993) but it's rooted in decades of hands-on experience with street trees — choosing, planting, maintaining, and managing the planting and maintenance, etc.

    Wicwas press: Garden Plants for Honeybees by Peter Lindtner. It covers trees, too.
    So, here's the test of my original question. Can you check and see if Garden Plants for Honeybees mentions the wind? I can't count how many web sites I looked at for lists of bee-friendly plants and trees, without seeing mention of the wind. How amazing it was to realize, finally, that there's an invisible common factor that determines which plants would be listed.

    If Lindtner's book mentions the wind, is it in a general "let's orient ourselves with the basic considerations" way, or is it in a breezy, incidental way? (Sorry, can't resist. ) This would be incidental: "Maples, which are basically wind-pollinated, provide a good early source for colonies when they first build up in the spring." Does it even say anything like that, specifically for maples?

    Wicwas also has a new book out (which I have not seen, yet) called The Flower and the Bee, by John Lovell...
    Ah ha! Now we're moving into the territory I'm curious about. Yay! From the blurb for The Flower and the Bee:

    The book presents the function of bees, beetles, flies and the wind in the pollination of flowers, which have evolved in accordance with their ability to attract and secure the largest number of pollen-bearing insects. The book is the first popular exposition for amateur gardeners, bee-keepers, and flower-lovers of the very far-reaching subject of pollination in general.

    Yay! other species of insects, and yay, finally! the wind. Thank you.

    It's nice to have folks here who know enough and are willing to answer honest questions. The hard part I've found is getting the questions right. Thanks for helping with that. There's more room on the general topic. And here in the 'Garden/Planting for Bees' corner of Beesource we can go on about individual species as well. One part of the topic that I'm finally catching on about is the qualities of pollen coming from the trees (and other plants) that don't really need flying insects for pollination. And a scrap of a question relates to which of those trees and plants offer nectar at all, EFNs or other sweetness. And why?
    Last edited by Kofu; 11-01-2015 at 02:40 PM.

  10. #10
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    Default Re: Wind pollination...

    Quote Originally Posted by Kofu View Post
    Yay! From the blurb for The Flower and the Bee:

    The book presents the function of bees, beetles, flies and the wind in the pollination of flowers, which have evolved in accordance with their ability to attract and secure the largest number of pollen-bearing insects. The book is the first popular exposition for amateur gardeners, bee-keepers, and flower-lovers of the very far-reaching subject of pollination in general.
    Okay... As it turns out, the book was published in 1918! That's okay. I ordered it. Wicwas Press is a good group of people and they deserve our business. This book might even be the best information on the topic available today for the general reader (and the muddling-along beekeeper).

    It's also available online, but I think it helps to have a physical book if you actually want to read it, reread it, carry it around to show others, etc.

    Here are two lines from the book that go right to the crux. Amazing that with all this information at our fingertips, we know so little...


    "Difficult as the problem once seemed (in the early 1800s), there is no longer any mystery why the flowers of many forest-trees appear before their leaves. They are or were in time past pollinated by the wind, although the willows and maples have in comparatively recent years changed over to insect pollination." — John Lovell, 1918.
    Last edited by Kofu; 11-02-2015 at 07:08 AM. Reason: added the snippet from Lovell's book

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