Tree of the month – Liquidambar (sweet gum)

A rather unknown species, this tree’s bright colours during the autumn months are spellbinding. With the season of colour coming to an end as we move into the Christmas period (who’s excited?), November’s ‘tree of the month’ is liquidambar, also known as sweet gum… and hazel pine… and, well, a lot of other names too.

What’s in a name, anyway?

Liquidambar styraciflua is a tree with many, many names; across the world it’s known as sweet gum, American storax, liquid amber, hazel pine, satin walnut, bilsted, redgum, star-leaved gum or alligatorwood to name a few. We’ll admit it’s rather confusing, so for the sake of this article we’re going to call it sweet gum.

Even if we can’t decide on its name, one thing everyone can agree on is the tree’s beauty during the autumn season, when its fresh green leaves transform into a riot of magnificent reds, pinks, purples, yellows and apricots. It’s a sight to behold, and if you love seeing autumnal colours in your garden then you can’t go wrong with planting a few of these large, deciduous trees in your garden. They grow well in lime-free soil, positioned in sun or partial shade, and are also suitable for planting in woodlands.

A tree by any other name would smell as sweet…

Native to warmer eastern US and Mexico, we saw these trees introduced to Europe in the 1600s, with the first planted in Fulham Palace Gardens in London by John Bannister. With its similar looking leaves, you’d be forgiven for mistaking sweet gum for maple. It produces a very sweet, fragrant resin from the bark when cut, which is still collected and used for incense, perfume and adhesives in Mexico. If you ever come across one when walking in the woods, you’ll find that crushing the leaves in your hands gives a pleasant scent.

Stuff that weighs upon the heart…

Older sweet gum trees have a large heartwood, which is the stronger, dead wood in the centre of a tree’s trunk. Heartwood usually contains tannins which make the wood a darker colour, and you’ll find that the sweet gum’s heartwood has a particularly dark colour to it. This heartwood is commonly called redgum in the industry and looks very similar to cherry. The lighter, pinkish sapwood, which is called sapgum, is found in the outer circles of the tree trunk. Most sweet gum lumber produced will be predominantly cut from sapgum, with various amounts of the inner redgum wood present.

Because of its high shrinkage and interlocked grain, sweet gum timber requires special attention during the drying process, so it doesn’t have the best reputation in the market. However once dried and kept in controlled conditions, it becomes stable like any other wood.

Redgum was highly valued in the early 1900’s, and used for furniture, cabinets, millwork, moulding doors and panelling where a decorative effect was desired. Redgum was sold in Europe as ‘satin walnut’, but slowly replaced with sweet gum, the tree’s sapwood, which itself declined in popularity and is now one of the lowest valued hardwoods available. Redgum, however, is now considered a speciality product and some timber is still produced. Redgum in older American houses and furniture is often misidentified as cherry wood.