The oak tree unfurls its leaves during the spring time and develop flowers which, when pollinated correctly, produce new acorn growth. Acorns are a source of food for insects, birds like the blue jay and ruffed grouse, as well as woodland creatures like squirrels, chipmunks and deer.
A Monoecious Tree
Oak trees are monoecious in nature, meaning they have both male reproductive parts (staminate) and female reproductive organs (pistillate) on the same tree. This allows for asexual reproduction. Oak trees are also often pollinated by other oak trees in the surrounding area.
The flowering of the oak tree occurs when temperatures begin to rise in the spring. Red oaks flower around two weeks earlier than white oak trees, says the University of Tennessee. Male flowers are visible to the naked eye. Long, worm-like tubes hang down from newly formed branches. This is the central stem for the male flowers, called catkins, which grow along the central stem like beads on a string. Female flowers require a magnifying glass to see. They are found on newly formed branches in the crown area of the tree and resemble leaf buds. They appear one week after the male flowers. Female flowers have a reddish stigma.
The male flowers produce pollen in mid-April. Pollen is shed from the tree for a period of one or two weeks and travels along the air. This can cause headaches and sniffing noses for allergy sufferers. The pollen attaches itself to the stigmas of the female flowers. The stigma transfers the pollen to the ovules located at the base of the flower. The ovum is fertilized and will mature into an acorn.
An acorn has the ability to create a new tree once it germinates. Most acorns do not survive to sprout and mature into a tree. Most acorns become food for wildlife, fungi and insects. Some oak trees do not produce a heavy crop of acorns, and some are genetically poor producers says Jay Hayek of the University of Illinois. Red oak trees only produce heavy acorn crops every three to five years. White oak produce heavier crops every four to seven years.
Pollination may not occur some years due to poor conditions. Heavy rains and humidity prevent the spreading of pollen. Drought as well as extreme dips or rises in temperature also prevent pollination. Early or late frost may damage flowers and their reproductive elements. Pest and disease may also affect the situation.