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TT: Re: Locust, Diatribe II
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As a horticulturist involved mainly in propagtion, I find your comments
interesting.
We are unfortunately stuck in the "Ligustrum Cycle", a theory involving
plants grown
by nurseries, installed by landscape contractors, purchased by retail
customers,
and "specked" in by landscape architects and thus a cycle. It is a question
where it begins and ends. I do not propagate inferior trees inspite of
numerous requests and thus an easy sale(ornamental pears,weeping
willows,etc.),but I have few requests for trees like American
Yellowwood(C.kentuckea) andChinesePistache(P.chinensis) that are superior
but are slow sellers.
I first heard of the "Ligustrum Cycle" from the late J.C.Raulston from NCSU
when I was a lowly undergraduate 10 + years ago. He is greatly missed.
Good topic, Mr. Kimmerer. BTW, 'Inermis' is the only one I would grow.
craig/athens,ga.
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> From: Thomas W. Kimmerer <tkimmer@pop.uky.edu>
> To: Community_Forestry <TreeTown@Majordomo.Flora.Com>
> Subject: TT: Locust, Diatribe II
> Date: Thursday, January 08, 1998 11:13 AM
>
> -----------------------------------------------------------------------
> Some notes on locusts, and a further diatribe on genetic diversity. You
can
> find more on my web site, listed below.
>
> 1. Thornlessness in locusts cultivars do not arise from breeding and
> selection, but from people finding spontaneous mutants in the field. The
> very popular moraine locusts (thornless honeylocust, Gleditsia
triacanthos
> inermis) are propagated as seedlings and clones from a single huge tree
in
> western Wisconsin. These breed true, so seedlings are also thornless.
Some
> of the more recent cultivars are from selection efforts, but I believe
that
> even these originate from the thornless trees found in the wild. Perhaps
> some of the horticulturists on the list could comment. In any case,
progeny
> of thornless females are generally thornless, and thornlessness is a
natural
> trait.
>
> 2. Black locust, Robinia pseudoacacia, is an important early
successional
> species. Originally from the Appalachians, its range was greatly
increased
> by Native Americans and by pioneers, especially for living fences (as
with
> our friend Osage-orange). Today, it is the most widely planted North
> American tree in southern Europe and North Africa. Here at home, the
tree
> is beset with difficulties. It not only has serious borer problems, as
> Thomas Palmer pointed out, but also has a leaf miner that turn the leaves
> brown by mid-summer in most of its range.
>
> 3. Ron Neely is right on the money when he suggests that we should be
> selecting for "polite" trees for cities. I see nothing wrong with
thornless
> or fruitless cultivars, provided that adequate genetic diversity is
> maintained. I do, though, have a problem (and I hope we all do) with
> covering entire cities with single clones of desirable cultivars. The
> danger of horticultural selection is not the introduction of thornless or
> seedless cultivars, but the drastic narrowing of the genetic base
presently
> under way. How many of us are aware, for example, that the largest
> wholesaler of red maples is selling only two genotypes, or that the
"modern"
> honeylocust are mostly of clonal, not seedling origin? We who are
> interested in community forestry, rather than just in planting trees,
ought
> to be pressing the horticulture industry to abandon the current practice
of
> producing huge numbers of single clones of trees. We need to restore
> biodiversity to cities not only by increasing the number of species, but
> also by increasing the number of genotypes within species.
>
>
> Tom Kimmerer
> Forest Biologist
> University of Kentucky
> Lexington KY 40546-0073
> 606-257-1824
> Fax 606-323-1031
> tkimmer@pop.uky.edu
> Visit the TreeWeb at http://quercus.uky.edu/treeweb
>
> -----Original Message-----
> From: Owner-TreeTown@listbox.com [mailto:Owner-TreeTown@listbox.com]On
> Behalf Of Thomas Palmer
> Sent: Thursday, January 08, 1998 9:45 AM
> To: TreeTown@Majordomo.Flora.Com
> Subject: TT: Re: Locusts
>
>
> -----------------------------------------------------------------------
> Here at Boston's southern edge, black locust is a common colonizer of
> disturbed areas, often forming large patches (as if it spreads by root
> suckers--does it?)
>
> A longhorn beetle whose grubs inhabit this species, the locust borer, is
> also common, and the yellow-striped adults are conspicuous on patches of
> goldenrod in late summer. Perhaps they are responsible for large amount
of
> deadwood seen amongst most locusts' smaller branches.
>
> The locusts leaf out quite late--well into May--apparently later than any
> other local species. One drawback to them is that their shade is so
light
> that barbarous thickets of multiflora rose can flourish underneath them
for
> many years (these thickets fade rapidly under maturing black cherry,
etc.).
>
> Thornless honey locusts are common in street plantings, but do not
> apparently escape. There are, however, a few heavily-armed examples of
the
> parent species adventive here and there (they are not native to the
area).
> Does the thornless habit breed true? Are the thorny adventives
descendants
> of the thornless plantings?
>
> Thomas Palmer
> Milton, MA
>
>
>
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