Sweetgum (Liquidambar straciflua), also called Redgum, Sapgum, Starleaf-gum, or Bilsted, is a common bottomland species of the south where it grows biggest and is most abundant in the lower Mississippi Valley. This moderate to rapid growing tree often pioneers in old fields and logged areas in the uplands and Coastal plain and may develop in a nearly pure stand. Sweetgum is one of the most important commercial hardwoods in the southeast and the handsome hardwood is out to a great many uses, one of which is veneer for plywood. Birds, Squirrels, and chipmunks eat the small seeds. It is sometimes used as a shade tree.
Fruiting heads often remain on trees over winter. Fair seed crops occur every year and bumper crops about every 3 years. The staminate and pistillate of Sweetgum is monoeciouse. The small, greenish flowers bloom from march to early May, depending on latitude and weather conditions. Both the staminate and pistillate flowers occur in heads. The staminate inflorescences are racemes; the solitary pistillate flowers are globose heads that that form the multiple head, 2.5 to 3.8cm in diameter, of small, two-celled capsule. The lustrous green color of the fruiting heads fades to yellow as maturity is reached in September to November. The beaklike capsules open at this time, and the small winged seeds, one or two per capsule, are then readily disseminated by wind. However, the seed balls can be safely collected for seed examination several weeks before ball discoloration occurs without harming the seed. Empty flowers are quit sensitive to cold and often damaged by frost.
Few data are available on the early development of natural stands of sweetgum throughout its broad range. The limited, earlier data indicate that that workers were not aware of the tendency of sweetgum to regenerate from root sprouts that originated from suppressed root buds. Stand disturbances thought to produce ideal seedbed conditions were actually optimum conditions for suppressed bud release and subsequent root sprout development. A South Carolina Coastal plain area thought to have successfully regenerated with sweetgum seed trees was later found to be regenerated primarily from root sprouts.
The importance of root sprout formation with sweetgum regeneration is evident from observations made in natural stands of mixed pines and hardwoods in Georgia Piedmont that have been logged for sawtimber. In most of the stands examined, advance reproduction of sweetgum was clearly evident, accounting for 10 to 60 percent of all hardwood production. The invasion of such stands by young sweetgum has usually been attributed to natural seedling, but most of the young, vigorously growing stems observed in the Georgia Piedmont were of sprout origin. It is not uncommon to find as many as 40 or more stems from seedling to sapling size on the root systems of a single parent tree. Additional work with root sprouts in Coastal Plain of South Carolina showed that sprout height after 8 years directly correlated with the diameter of the lateral root from which the sprout originated; the larger the root the taller the sprout. The persistence of root sprouts was revealed when soil was removed from several plots on a Georgia Piedmont bottomland site that supported pure stands of sweetgum. Trees ranged in d.b.h. from 25 to 41 cm and varied from dominant to intermediate in the crown canopy. More than 70 percent of seed origin were later found on abandoned agricultural lands. These observations indicate that significant portion of sweetgum regeneration following logging can be expected to originate from root sprouts. The long-term development and management of these stands have yet to be clarified.
Plantation establishment of sweetgum is becoming increasingly important throughout the southern region, and it is rapidly becoming the hardwood species most commonly established. Results of early plantation establishment and development have been quite variable. This variability in growth has been attributed to seedling quality. Seedlings with large root-collar diameter achieve the best growth, and planting seedlings with a root-collar diameter of less than 6 mm is not recommended. In Georgia Piedmont bottomland site, seedlings at age 7 ranged in height from 3.8 to 6.2 in. after 7 years on a strip mine in Indiana, sweetgum averaged 2.1 in. on favorable sites in the lower Mississippi Valley, and seedling height growth of .6m/yr has been reported. On upland sites, 5- year growth varies considerably, from 1.1 in on an eroded field to 2.0 in. on areas reverting to woody cover. It is slow, early growth of sweetgum plantations that is of concern to silviculturists because it necessitates expensive cultivation to reduce weed competition and thereby maintain acceptable survival until height growth begins. First-order lateral root morphology of

Nursery-lifted sweetgum seedlings reflects their future competitiveness in the field. Early growth and survival can be acceptable. Even in moderate to severe drought years, if nursery-lifted seedlings have 5 or more first-order lateral roots exceeding 1mm in diameter at the junction with the taproot. As many as one third of all seedlings in selected families growing in one nursery did not meet these standards making them poorly competitive in a forest environment.
Trees begin to produce seeds when 20 to 30 years old and continue production until at least 150 yrs of age. Seed production varies widely depending on climatic conditions during the growing season. Under optimum conditions, seed balls may average as many as 56 sound seeds per ball, or as few as 7 or 8 under less favorable conditions. Seed balls have been collected for more than 12 yrs at the Forestry Sciences Laboratory, Athens, Georgia and scientists there expect 20 to 30 sound seeds per ball in an average year but have found as few as 5 per ball in a bad year. Low percentages of sound seed appear to be correlated with prolonged summer drought and excessive soil moisture stress during the growing season in northeast Georgia. There are approximately 365g of clean seeds per 35.

Sweetgum 9 of 10 on the basis of 2655 Review.