White oaks are the most important tree species to wildlife in Kentucky forests.
The acorns they produce are a critical food source for squirrels, white-tailed deer, wild turkey, black bear and many non-game species. White oak acorns are preferred by wildlife because they are more palatable. Acorns produced by red oaks contain tannin, which makes them bitter.
White oaks can produce acorns every year but entire crops are often lost due to late freezes or heavy rains just as oak flowers are pollinated. Summer droughts can also impact acorn production, by stunting or killing acorns.
But spring is when developing acorns are most affected by weather anomalies.
According to the University of Kentucky Cooperative Extension Service there are 10 native species of oak trees in Kentucky. Six species are members of the red oak group, including the Black Oak (Photo Provided)
The oak’s female flowers that produce acorns are very small. Internal timers tell the trees when to open their buds in the spring. Once the buds flower, the blooms are open for only a week, during which time they are wind pollinated (anemophily).
However, a late frost during the time the flowers are open stops the flowering process. If that happens, the results show up in the fall with a greatly limited nut production regardless of what happens with the weather in the summer and autumn.
Because it takes two years for red oak acorns to mature, and not all trees produce mature acorns in the same year, red oaks are a more reliable source of acorns on an annual basis.
The ideal situation for landowners managing for wildlife is a mix of white and red oak species. This will ensure that some acorns will be there for wildlife when there’s a failure of the white oak crop.
The Chinkapin Oak , a member of the white oak group, is found in rich soils with limestone outcroppings. Its small acorns are a favorite with wild turkeys (Photo Provided)
Late winter is the best time for chainsaw work, clearing away small cedars, cutting grapevines, and the saplings of shade-tolerant trees (maples) from around your oaks. By removing competition oak trees will get more sunlight and moisture to help them grow.
Kentucky’s 10 Native Oak Species
According to the University of Kentucky Cooperative Extension Service there are 10 native species of oak trees in Kentucky. The six members of the red oak group are:
— Black Oak, Quercus velutina
— Northern Red Oak, Quercus rubra
— Pin Oak, Quercus palustris
— Scarlet Oak, Quercus coccinea
— Shingle Oak, Quercus impricaria
— Willow Oak, Quercus phellos
The four members of the white oak group are:
— Bur Oak, Quercus macrocarpa
— Chestnut Oak, Quercus prinus
— Chinkapin Oak, Quercus muehlenbergii
— White Oak, Quercus alba
Typically, it takes an oak tree about 20 years to start producing acorns. That’s why it’s critically important to remove competing vegetation, and vines, from around oak trees.
In the U.S. Forest Service’s Wildlife Habitat Management Handbook, published in 1981, it was reported that at their peak of production the two white oak species in Kentucky that produce the highest yields of acorns are: the white oak (Quercus alba), followed by the chestnut oak (Quercus prinus). For red oaks, the top producers are the northern red oak (Quercus rubra), followed by the scarlet oak (Quercus coccinea).
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The leaves are a good way to tell the difference between white oaks and red oaks.
White oak leaves are narrower (about four inches) and have rounded lobes. Red oak leaves are wider (as wide as six inches), and have pointed lobes.
Although oaks are considered intermediate in their tolerance to shade, they grow best on sites with openings in the forest canopy and minimal competition for sunlight, water and nutrients from other plants. Oak stands regenerate naturally by sprouting acorns and stump sprouts.
Annual Mast Survey
Since acorns and other hard mast are so important to wildlife, biologists of the Kentucky Department of Fish and Wildlife Resources began an annual mast survey in 1953 to assess each year’s crop of nuts.
Biologists walk the same route every year, and determine the proportion of trees bearing hard mast, by observing nuts on hickories, white and red oak, and beech trees. The mast survey helps biologists predict game availability and behavior.
For example, each year’s estimate of the number of squirrels available to hunters is based on the previous year’s mast crop. In years when the mast crop is sparse, deer and wild turkey are more vulnerable to hunters because game must move around more to find food. In years of plenty, deer and turkey harvests are likely to decrease, because food sources are available everywhere so there isn’t as much game movement.
Acorns begin to mature in mid-September. Kentucky’s annual mast survey is typically conducted between Aug. 15 and Sept. 1.
If wildlife is the goal of the forestry management plan on your property, protect and encourage oak trees. They are the key food source all the wildlife species you want to observe or hunt on your forest lands.
Art Lander Jr. is outdoors editor for NKyTribune and KyForward. He is a native Kentuckian, a graduate of Western Kentucky University and a life-long hunter, angler, gardener and nature enthusiast. He has worked as a newspaper columnist, magazine journalist and author and is a former staff writer for Kentucky Afield Magazine, editor of the annual Kentucky Hunting & Trapping Guide and Kentucky Spring Hunting Guide, and co-writer of the Kentucky Afield Outdoors newspaper column.
