Hickory trees, belonging to the genus Carya, are large, deciduous hardwoods native to the forests of North America. These trees are valued for their strong, dense wood and, in some species, their edible nuts. The final height a hickory tree can reach varies significantly, depending on the specific species and the environment in which it grows. Certain conditions allow them to develop into some of the tallest trees in their native habitats.
The Range of Heights by Species
The maximum height of a hickory is divided between the “true hickories” and the taller “pecan hickories.”
True Hickories
True hickory species, such as the Shagbark Hickory (Carya ovata) and Mockernut Hickory (Carya alba), commonly mature between 70 and 100 feet tall in a forest setting. Shagbark Hickory, recognizable by its peeling bark, frequently reaches heights of 120 feet, though specimens up to 150 feet have been documented. Mockernut Hickory typically grows to about 90 to 100 feet, occasionally approaching 130 feet in height.
Pecan Hickories
The pecan hickories, which include the commercially grown Pecan tree (Carya illinoinensis), are generally the tallest members of the genus. Pecan trees routinely grow to heights of 70 to 100 feet, but they are known to reach exceptional sizes of 130 to 180 feet. These towering dimensions make the Pecan one of the largest native trees in the eastern United States.
Factors Influencing Mature Size
While genetics establish the potential maximum height, several environmental factors determine the final size a specific hickory tree achieves.
Soil and Moisture
Soil quality is a limiting factor, as hickory trees require deep, fertile, and well-drained soil to support their size and accommodate their deep taproots. If the soil layer is shallow, rocky, or poorly drained, the root system cannot expand sufficiently, which limits vertical growth. Moisture availability is also a major influence, as hickories thrive in humid climates with consistent water, though they become drought-tolerant once established.
Competition
Competition for resources, particularly sunlight, plays a large role in a forest environment. Trees growing in dense, mixed stands often grow taller and straighter as they race their neighbors for light. Conversely, those planted in open yards tend to develop a shorter stature with a broader, more rounded crown. The combination of these conditions must be ideal for a hickory to approach its genetic height potential.
Growth Rate and Timeline
Hickory trees are known for their slow to moderate growth rate, especially during their early developmental stages. Newly planted hickories often prioritize establishing a deep taproot, which is why vertical growth can be minimal, sometimes only 6 to 12 inches per year for the first few seasons. Once the root system is established, the growth rate typically accelerates, with many species adding 1 to 2 feet of height annually under optimal conditions. Pecan trees are an exception and are considered a faster-growing hickory, sometimes averaging up to 35 inches of height gain per year on rich, loamy soils. Reaching their full mature height is a long-term process for all hickories, frequently taking 50 to 100 years or more.