Tree 10 of 10 in parkland Tree Trail (complete set).
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Your description is "untoothed except for 1-6 big teeth at base of each leaflet" yet your photo shows leaflets shallowly toothed (forward pointing) all the way round the margin.
Also, Ailanthus alt. leaves have a quite distinctive asymetrical first "tooth" on the trunkward side of the leaflet.
This looks more like Juglans nigra to me - another malodorous tree - which is described as having slightly twisting large branches.
Perhaps you could slice open a twig longitudinally to check if it has chambered pith (walnut) or not?
How to take close-ups with cheap phone and hand-lens:
Field Guides for Budding Botanists:
Definitely not Ailanthus, which has petiolate leaflets, the leaflets on this plant are sessile. So probably Juglans nigra as Rachy suggests, but Pterocarya fraxinifolia (Caucasian Wing-nut) looks similar. Pterocarya species also have the same chambered pith in the twigs as Juglans has.
Id taken from metal plate on ID post. Description from Collins Tree Guide. Park has a really good Green Flag standard gardener whose horticultural skills are recognised e.g. borders in Walled Garden. Regards
Steve, I'd forgotten that Wingnut also has chambered pith, so thank you for that reminder, and yes, I did consider a Wingnut as a possibility, but I felt that Walnut was more likely in this case as the leaflets are not quite evenly opposite. Well done with the point about the leaflets of Ailanthus being petiolate (stalked), I should have said that - Hugh, if you look up Ailanthus in your Collins, you can see what this means.
Hugh, you took the description from a good reference book, but that description of the leaf margin does not match that of your specimen. When this happens, it is time to check into alternatives.
In fact, I hate to say this, but it is probably better to get in the habit of writing your own description of the specimen, and only then comparing it to that in the reference book. If you look again at the leaf margins in your photo, you can see that they do not match your book's description.
Labels Can Be Wrong. Anyone who has ever worked in a garden/arboretum open to the public will tell you that people steal labels, or change them around: don't ask me why. Sometimes mistakes are made when replacing them. Worse, the owner may have ordered tree X, but on arrival they may well get tree Y. This happens more often that you might think.
I mean no disrespect to your Park's gardener (although in my world, Green Flag is a car break down recovery service) but unless they are also a tree expert, they could just be accepting what was on the ID post before they arrived.
I would still be interested for you to go and get a twig to check the pith.
Rachy, thanks for your comments. I have revisited the tree in question and made a closer examination, including bark. I have compared the similarities and differences with Black Walnut and Caucasian Wing-nut. I will visit again when the tree is in flower as there may be some hybridisation and let you know the outcome. Kind regards
I agree with Rachy's comments above about mislabelling and your description not matching the actual tree. I don't think this is Caucasian Wingnut in which the leaflets are stalkless and slightly overlap the stalk at the base. This species tends to sucker profusely - no sign of this in the photo (not conclusive, of course). Long time to wait for flowers - any sign of fruiting?
This is a very good test for narrowing down the possibilities - if you don't feel comfortable snapping off an inch or two from a live branch, just look under the tree for a fallen branch or twig: then take a penknife and cut it in half lengthwise.
This might save us all having to wait on tenterhooks for flowering/fruiting time! Especially as it looks like quite a young tree...
Lat/Lng: 53.3803, -2.8714
OS grid ref: SJ421874
Small 14 acre, Green Flag park in Conservation area on high sandstone ridge.