Oaks & Acorns: The Mystery of the Mast

Did you know that the Oak trees of North America produce more nuts than any other tree region worldwide, cultivated or wild?

The fruit of an Oak tree is an acorn. A single giant Oak tree can produce nearly ten thousand acorns in a reproductive season. However, Oak trees do not bear fruit every year and some acorns require up to 18 months to mature. When a forest nut-bearing tree, like an Oak, Pecan, or Walnut, produces a high yield or bumper crop, the year is botanically referred to as a 'mast' year.

 The Big Tree is a coastal live oak, Quercus virginiana, Goose Island Oak Tree, The Botanical Journey

This 'Big Tree' is a coastal live oak, Quercus virginiana, and has lived more than a thousand years along the Texas Gulf Coast. Many of the surrounding oak trees are its offspring. How many mast years has this mighty tree experienced?

What is a Mast Year?

Mast is a term used to describe the fruit of forest trees and shrubs. The fruit can be hard nuts, like acorns or beechnuts, or soft, like blueberries or wild grapes, and are an important food source for wildlife. A mast year is when a particular woodland species produces more fruit than normal. Like many trees, Oaks have irregular cycles of high and low yields. Oak masting happens every 2- 5 years.

Why Do Oaks Mast?

Scientists are uncertain as to the exact reason why oaks and other plants mast but there is a range of theories from climate temperatures and rainfall amounts to harsh summers affecting acorn production or the availability of spring winds during pollination. The specific causes remain a mystery, but one undeniable evolutionary benefit of masting is... ensured future offspring.

Mexican White Oak, Oak & Acorns, Oak Tree, Mast, Masting, Mast Year, The Botanical Journey

Acorns are the easiest way to identify an Oak tree. There are over 600 species of Oak trees with more than 200 species endemic to North America. This elliptical oak shaped leaf indicates a Mexican White Oak tree and can be found growing as far south as Guatemala.

In mast years, acorns fall by the thousands increasing food availability for squirrels, mice, birds, and other forest frugivores. During mast events, dependent wildlife populations increase. The following year, the trees will bear little to no fruit due to the abundance of energy required to produce the previous year's bountiful harvest. In subsequent low to no yield years, wildlife populations decrease as food becomes scarce. Then in a mast year, the overflowing harvest will more than feed the forest critters and ensure some seeds left to grow into future oak trees.  

Oaks & Acorns, Mast Year, Oak Nuts, The Botanical Journey
Surely, one acorn will grow into a majestic oak tree?

 Oaks in Peril

Imagine driving down a country road, sun shining over rolling meadows of green grass only to be delightfully interrupted by a large Oak tree standing gloriously alone. Romantic, yet a cause for concern. Many new Oak trees in the United States are planted on private properties. The forests are rapidly changing. Oaks are at risk due to logging, diseases, insect invaders, drought conditions, wildfires, and urban sprawl. California has the most native species of Oak trees than any other state. The extended drought and the wildfires of 2017 and 2018 devastated the Oak populations. The Botanical Journey is working with OneTreePlanted.org to help plant Oak trees in the areas of California devasted by the wildfires. We have created a $1000 fundraising campaign. One dollar plants one tree. Click the acorn link below to help support reforestation efforts. Together we can replant the forests of California helping wildlife and future generations to enjoy the native forests we enjoy today.

Plant A Tree, The Botanical Journey, One Tree Planted, Fundraiser Campaign 


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