The Northern red oak (Quercus rubra) is often called the common red oak, gray oak or Eastern red oak. Widely grown for its lumber production and as a shade tree, the red oak grows up to 60 feet in height, with a canopy width of 70 feet. The tree's native range runs from Nova Scotia, Canada to Georgia and as far east as Oklahoma.
The red oak is monoecious, which means it is self pollinating. The tree will produce both male and female flowers in April and May. The flowers appear at the same time the tree's foliage begins to sprout forth.
The red oak produces acorns from August into October. The acorns grow either singularly on tree limbs or in large clusters. Acorn production will not begin until the red oak is at least 25 years old. Acorn production is sparse until the tree reaches 50 years of age, and then it swings into full reproductive production. The crown size of the tree appears to dictate whether the tree will produce abundant acorns or not. The larger the tree's canopy, the better the acorn crop each year.
According to the U.S. National Forest Service only One percent of the red oak's seeds are viable and will produce a red oak tree. It is estimated that it often takes over 500 acorns to produce one red oak seedling. The acorns are not only affected by viability issues, but also easily consumed by wildlife before germination can take place. Wild turkeys, deer, squirrels, rodents and even insects enjoy eating acorns.
In order for acorns to germinate they must be covered with a thin layer of soil in the springtime. Ideally, leaf litter should also be spread over the acorns to offer the ideal germination conditions. Acorns on top of the soil will not germinate because they will quickly dry out.
Prior to the seed producing top growth, it first begins to establish a deep taproot system. Once the taproot is established, very little can come in the way of the seedlings' growth.
A red oak seedling requires at least 30 percent of the forest light to reach its foliage in order to successfully grow. Unfortunately, in a thick forest cover with other conifers and trees that stand far taller than the tiny red oak seedling, the light is often blocked out, and only 10 percent of the sunlight will reach the seedling. This lack of light will often result in the young tree's death.
Death of Top Growth
The red oak seedlings that receive enough light can be killed by fire or wildlife, and still regrow off the deep root system it has established. It is believed that many red oaks have root systems that exceed their top growth's lifespan by 10 to 15 years because of the top of the young tree dying back and regrowing often.