The species Ulmus parvifolia grows to 20m in its native southeast Asia, but this dwarf cultivar, ‘Seiju’ Chinese elm or ‘Seiju’ lacebark elm, will only reach 2-3m under the best of conditions. In this case, though, the physical restrictions on growth caused by being planted in a trough likely means this tree will not grow much beyond its current size. ‘Seiju’ is a sport selection of Ulmus parvifolia ‘Hokkaido’; ‘Seiju’ is differentiated by its larger leaves and faster rate of growth.
Trough gardening has long been associated with growing alpine plants, including dwarf trees and shrubs. If you’re interested to learn more about troughs, check out this article on trough gardening for tips on how to build a trough and selecting appropriate plants.
Photography resource link: Understanding Histograms via The Luminous Landscape’s Tutorial Series (as of mid-2017, now requires a subscription). Nine times out of ten, I look at the histogram after taking a photograph and decide from that whether I need to take another photograph with a different exposure. How important is this? Well, the article concludes with: “It’s the greatest invention since the built-in light meter”.