Acer circinatum not on Vancouver Island?

Discussion in 'Maples' started by Margot, Jun 3, 2020.

  1. Margot

    Margot Contributor

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    Does anyone know why Acer circinatum is almost non-existant on Vancouver Island? If you look on this E-Flora BC map, you can see that it grows prolifically on the BC mainland and in Washington State - but hardly at all on VI. I brought one with me when I moved to to the Island 14 years ago which has grown tall but never produces seeds. Very strange, wouldn't you agree?

    E-Flora BC: Interactive Map
     
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  2. Acerholic

    Acerholic Esteemed Contributor Forums Moderator VCBF Cherry Scout Maple Society

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    @Margot, good morning Margot, I've just looked at your map and that's fascinating. I'm unfamiliar with the area so can only offer an opinion in that the Vine maple is not endangered in anyway. Hence it is not a tree sought after by enthusiasts etc, so not thought of or purchased to grow other than in areas where it naturally occurs as shown on your map

    Geologically speaking it does not appear that Acer Circinatum should not do well where you are now in comparison to where it is growing well as shown on your map.
    It's interesting though that yours has never produced seed, that could be the clue on VI.

    Perhaps you will start a trend. These things have to start somewhere. A neighbour might see yours and buy one and so off it goes.

    Anyway it's just a thought. An interesting post to get people thinking today Margot.

    D
     
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  3. emery

    emery Generous Contributor Maple Society 10 Years

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    What a great tool. It does look like the Island is right at the top of the range for the maple. But most of the data points for wild incidence seem to come from the U. of Alaska, and there are none from UBC on the island at all. I wonder if UBC simply hasn't surveyed it for this plant.

    The vine maple and it's cultivars are relatively popular in gardens in the US and Canada, (though nothing like their Japanese cousins), less so in Western Europe and UK as they can be very tetchy to grow here. I don't know why my ungrafted species or the few cultivars I've planted do so well here.

    As for flower and seed, that's always a complicated question: it's not uncommon for individuals to take 30 years to set seed, or only a few. I don't have any good insights into why flowers/fruit occur when they do, except the usual observations that maples fruit heavily after a stressful year, or if they're about to die.

    -E
     
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  4. 0soyoung

    0soyoung Well-Known Member

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    I don't know why they do not occur naturally on any of the islands in the area. I haven't scoured all of the San Juans, but there are no 'wild' ones on Fidalgo. The most interesting Interactive Map plots two sightings on Fidalgo. One is in the parking lot of the Safeway store at 12th and Commercial = landscape planting, just like my tree. The other is in a residential area that is also (almost certainly) a landscape planting.

    Something like 5000 acres of Fidalgo Island are forest woodlands preserved either as WA state or Anacortes City Forest Lands. I've wandered all of it and never found a vine maple. There are more forest lands across the bridge on northern Whidbey Island. I've never seen them there either. Yet, I've seen many hiking guides and the like, saying they are here. I postulate that people are mistaking saplings of the abundant acer macrophyllum to be acer circinatum. Otherwise, I have no explanation for the misinformation, just as I have no explanation for why they aren't here, naturally.

    The only clearly native vine maples I have ever seen were up in the Cascades; most recently at a place called 'Thunder Knob'. I see three sightings indicated on the interactive map in this area, around the southern end of Ross Lake.
     
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  5. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Absence from islands hints at a less-than-perfect adaptation to the extremes of oceanic climates (mild winters, cool springs, chilly summers). Check perhaps whether in these conditions with warmer oceanic winters, it is tempted into flower too early in spring, and the flowers then get killed by late spring frosts. On the mainland the colder winters would keep it dormant until after the risk of damaging frosts is over in most years.
     
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  6. 0soyoung

    0soyoung Well-Known Member

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    My home is within a few hundred yards of the salty, 50F degree water. My landscape tree is 15+ years old now. It prolifically produces viable seed. They do not scatter far, however, which may be key. I have dozens of seedlings from my landscape tree that I grow, just for fun. This is one that is about 5 years old now. It has and continues to sit outside in my back yard all year round.
    IMG_20200511_150040497_HDR.jpg

    This is a climate in which they do thrive. Acer macrophyllum and acer glabrum found their way across the narrow straights to these islands, but acer circinatum seemingly didn't.
     
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  7. Ron B

    Ron B Paragon of Plants 10 Years

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    One could conclude San Juan County, Fidalgo Island and Island County are too dry for it. It can even be seen wild as close to Camano Island as Snohomish County ravines and uplands east of Stanwood, but not on drier Camano Island. Yet there's lots of them in Central Washington! Including a Tumwater Canyon site where during spring 2019 more than one wildflower species growing between the vine maples and the side road was already wilting in the oncoming seasonal dryness - before having flowered much, if at all. This while the maples were still in the process of leafing out. (And Lewisiopsis tweedyi - a very low annual rainfall indicator species - on a nearby slope were still in the early stages of flowering).

    Otherwise the UBC Press print publication Indicator Plants of Coastal British Columbia includes vine maple as one of the indicator plants that is profiled. (I no longer have a copy). Otherwise searching the web for something like "ecology (or silvics) acer circinatum" might turn up something.
     
    Last edited: Jun 6, 2020
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  8. AlainK

    AlainK Generous Contributor Forums Moderator Maple Society 10 Years

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    Very nice little tree. Judging by the scale given by the glove, I can see you've managed to reduce the leaves a lot, or maybe they're smaller on the plain species. The only circinatum I have is the 'Burgundy Jewel' I posted in another thread. The leaves are so big and the internodes so long that I didn't think it could be turned into a bonsai. Good job !
     
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  9. 0soyoung

    0soyoung Well-Known Member

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    Thankyou, @AlainK, but my point in including it in this thread was just to emphasize what a good climate there is here on Fidalgo Island for vine maples. Of course this bonsai is well irrigated which trees in the wild are not.

    The mother of this bonsai, my vine maple landscape planting isn't directly irrigated, but it may well have its roots in my neighbor's irrigated garden bed by now. Underneath my vine maple is bark mulch, now about a decade old and a a couple of inches deep. It is not all that different from the humus on much of the forest floor. A large number of seedlings sprout in this 'composted' bark mulch every year. They certainly depend solely upon rainfall, just as they would in the local forests. I have no doubt that I would have a small forest of vine maples beside my house if I didn't habitually pot them up for my entertainment.

    To me it all adds up to indigenous vine maples ought to be thriving on these islands, but they just aren't here. A relatively narrow channel of salt water is all that separates these islands from the shore lands where they do exist. It makes me think that acer circinatum evolved/appeared after acer glabrum and acer macrophyllum that are here. Possibly they (glabrum and macrophyllum) got here before these lands were islands, and acer circinatum arrived too late.
     
  10. Margot

    Margot Contributor

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    I can understand why the general area where I live on the east coast of Vancouver Island would be too dry for Acer circinatum to become an established understory shrub/tree. What puzzles me is why, in my own well-irrigated garden, a heathy, 10-foot specimen would produce little to no seeds and, whatever seeds are produced, never germinate. Temperatures in my protected garden seldom fall below zero degrees F and spring freezes are not an issue.

    When I lived on the Lower Mainland, BC, the same vine maples as the one I brought with me to the Island produced so many seedlings, I pulled them as weeds. They were much younger than mine is now.

    Since I have found a few seeds on my tree this year, I think I will plant them in pots so I can watch if they germinate.

    Thank you to all who have weighed in on this mystery.
     
  11. 0soyoung

    0soyoung Well-Known Member

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    @Margot, your lack of viable seed may be due to the lack of a pollinator. In another thread, @emery commented that japonicum and circinatum are difficult to distinguish at the current level of genetic analysis. I have an acer japonicum 'Green Cascade' within 50 feet upwind of my vine maple.

    Maybe you just need another vine maple (or a japonicum maybe) nearby to get viable seed.
     
  12. Margot

    Margot Contributor

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    I just found this very informative website from 1989 that I think explains why Acer circinatum doesn't thrive on Vancouver Island - mainly that it's too dry but also that reproduction by seed is limited.

    Following are a few selected sentences from the Acer circinatum report.

    REGENERATION PROCESSES :

    Vine maple is a very poor seed producer and relies primarily on vegetative means of reproduction.

    Vegetative regeneration: Studies indicate that vine maple reproduces almost exclusively by layering when under stands of old growth conifers.

    Seed production and dispersal: Vine maple begins to produce seed at an early age, probably before age 10. The flowers appear in the spring when the leaves are about half grown. Flowers occur in loose drooping clusters that hang from the end of the branchlets. Male and female organs occur in the same flower; however, in each flower only male or female organs are functional. Thus only a few flowers from each cluster develop into fruit.

    Seed viability and germination: Vine maple seeds have a dormant embryo which requires approximately 6 months of chilling to germinate. Under natural conditions the seeds are dispersed in the fall and germinate in the spring. Studies have shown that vine maple seedlings are rare or absent from both clearcuts and mature stands. This lack of seedlings may possibly be attributed to: (1) the consumption of a high proportion of samaras by squirrels, chipmunks, and insects, (2) a thick moss layer or dense growth of other shrubs which often prevents seeds from reaching mineral soil, and (3) poor germination.
     
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