The trees on this block are listed as being European Ash, but they're so striking that people on my walk thought they should be something special. This is just chlorosis, right? If wrong, then I'd want to know what cultivar.
In the contemporary view of that type (accounts of what its characteristics are have varied over time and more than one cultivar may have been grown under the name) yellow young branches are visible throughout the year, which I am not seeing on these trees. What we see planted around here these days has been sold in North America using the Golden Desert trademark; Jacobson, North American Landscape Trees (2006, Ten Speed, Berkeley) placed this under 'Jaspidea'. Another one Jacobson (same) mentions is 'Gold Cloud', patented in the US in 1963 and suggested by G Krussman to be a renaming of 'Jaspidea'. But the US introducer of Golden Desert = 'Jaspidea' disputed this ("in no way related"). Probably yellow twigs, yellowish leaves etc. on Fraxinus excelsior is something that recurs and has been propagated repeatedly, like partly yellow foliage on Thuja plicata, multiple different instances of which I have seen on trees here in this area - including the very top of a conspicuously located tree on SW Marine Drive at UBC.
I see that there's one called 'Allgold', which I thought in the photos looked, well, more all gold. Are you both implying that this could be some cultivar?
The trees look grafted and compact, but not yellow-twigged. The yellowing of the leaves is autumnal, unless you go back next year and they are also yellow during the summer. Often when you see a row of street trees that are all the same they are grafted anyway, even if not obviously a particular cultivar. Growers sometimes graft nameless forms, sell them as the typical species. Otherwise numerous named clones have been built up and circulated that have characteristics that aren't as obvious as weeping or erect branches, purple or variegated leaves etc.
Fraxinus excelsior - the natural wild type, not counting cultivars - doesn't turn yellow in autumn, the leaves drop green or green with blackish-brown edges. Around here (where it is the most abundant native tree) they are all still solidly green (despite a cool early Septenber) and likely to remain so for at least another 3-4 weeks, probably more, before falling. Just checked a couple more books - there is a yellow-leaved cultivar, 'Transoni'. Doesn't seem to be much info on it available. PS can you get a close-up of a shoot? Looks to me like they might be yellowish, but it's hard to be certain from the resolution of these pics.
This looks like what the Park Board lists as 'Jaspidea'. There are numerous examples around Vancouver—same age, same golden summer foliage, same autumn-visible variegation. This tree is on West 72nd Avenue around Selkirk Street.
Here are some close-up photos of the trees on 39th at Yew, showing yellow twigs and black buds. The trees are still looking beautiful.
