Tree of the Week: Sweetgum (Liquidambar styraciflua) and a special guest

Our tree of the week, a young sweetgum (Liquidambar styraciflua), grows on the grassy slope near Cline Hall Dormitory. It is pictured center (leaning to our left) alongside a groundsel bush (Baccharis halimifolia).

 

For the past few years we have recorded the development of this sweetgum on the blog. You can read about it here and here. Last year, this individual was tagged for removal, but for one reason or another, it thankfully remains standing.

Severe damage to its trunk was the reason it was tagged for removal. In 2020, the arboretum's squirrels made deep cuts into the bark. Why were they peeling bark from the tree? We're not entirely sure, but trees are probably very fond of owls, hawks, and snakes. Those wounds have healed, but the damage is permanent, making the tree susceptible to enemy invaders, particularly fungi and insects. An intact layer of bark is essential protection for a tree to last into maturity.  Consequently, we will be keeping an eye on this sweetgum; it is still a candidate for removal.

 

Looking at the bright green leaves, you wouldn't think that this tree was handicapped, especially if you look a little closer to notice the inconspicuous fruits, the infamous gum balls.

Allowing this young tree to stand another year or two ought to insure a replacement for the arboretum catalogue.

 

This sweetgum is also of interest this week because of its guests. Caterpillars have taken up residence in a few localized areas of the canopy. The caterpillars have built white, gauze tents among the leaves, which they are eating. According to our research, they appear to be fall webworms (Hyphantria cunea). Given the season and their activity, that common name makes a great deal of sense.

 

Although they produce a web-tent that some people might find "yucky," this silk might be worth its weight in gold. Unfortunately, it doesn't weigh much. The LSUAg Center informs us that while unsightly, fall webworms are not harmful to healthy trees.

These little fellows will eat the leaves of nearly a hunded of our native trees, so it's not surprising that they're chowing down on sweetgum, which is a choice of other caterpillars as well.

 

These are harmless insects. When they grow up, they will become beautiful white moths. Did you know that "White Moth" was Vladimir Putin's nickname when he was an intelligence agent? Secretive web-weavers.