Roots

All About Roots

By Madison Nef

The roots are one of the most important parts of a tree. They spread wide and far underneath a tree, keeping it grounded. While the roots are very important, they are also the least understood part of a tree due to the fact that they are below ground and out of sight. Roots have 4 largely important jobs:

·        They anchor a tree into the ground

·        They act as a pipeline

·        They absorb all the water and nutrients a tree needs to survive and function

·        They store extra carbohydrates that a tree needs if it cannot create its own food

There are a few different types of roots: structural roots provide the framework for supporting a tree. These roots grow thicker as they age, and are covered with a protective layer of bark (much like a tree limb). Then, there are tap roots… MOST trees have a taproot. A taproot is the largest of the roots, and it usually grows directly downward. A taproot will only form downwards if the soil is loose and not packed… most times, taproots are forced to grow lengthways because the soil is too firm.

When roots grow horizontally, they develop sinker roots that can grow through thicker dirt 3-7 feet down. Sinker roots are often thinner than the taproot (which can grow to be as wide as the tree itself when growing downward) and are more spread out. Their main purpose is to hold the tree in place in the ground.

10% of a tree’s mass is contained in its roots, which are found underground. Larger roots are used to store extra carbohydrates in the form of sugar, so that the tree has a good supply of sugar it can live off of in case of a dire situation, such as a drought. These large roots, while majorly important, barely make up even a fraction of all the active roots in the root system, however.

These roots, while small in comparison to all roots, have the largest responsibility out of them all. They are called “fibrous” roots and deliver essential water and nutrients to the tree. These roots are horizontal and widespread. These roots often make large clumps and mats in the dirt, which are responsible for absorbing all the water and the minerals which in turn go to the tree. To make this process more efficient, the roots are covered in tiny hairs.

The number of hairs a root has depends on its surface area… a root exposed directly to dirt will not absorb much. The more hair a root has, the more dirt the root is exposed to. The more dirt the root is exposed to… the more minerals and water it can absorb. These hairs definitely make the absorption process more efficient and easier.

The nutrients a tree needs travels through the root hairs through a process called osmosis. This is a Greek word, meaning ‘to push’. In this process, water dissolved with minerals moves through a semi-permeable root hair membrane; going from a high concentration in the soil to a low concentration in the root hair and membrane cells.

The minerals and water then move through a cortex, which takes the nutrients and delivers it directly to the tree when it is needed.

Root hairs generally increase in length in order to absorb more water. For example, a 4 month old grass plant has over 14 billion root hairs with an absorbing surface of 401 square meters and a total length of 10,000 kilometers.

Fibrous roots are ALWAYS growing to find new soil and new nutrients for their tree as they soak up the soil they are already in. However, when new roots form, they are very fine and weak until they start to absorb and age. To protect these fragile roots, the roots form root caps on the ends of them so they don’t get damaged while pushing through. While growing, a fibrous root’s cells are constantly being renewed as it snakes its way through the soil.

These roots spread so far… they often times spread up to 2-3 times the height of the tree. Soil type determines how far the roots spread- they grow faster and spread farther in sandy soil than in tough clay soil.

In conclusion: roots are amazing parts of the tree, and very important and crucial to a tree’s survival. Without roots… trees:

·        Would not be anchored to the ground, and would fall over

·        Would not have extra energy and nutrients stored for droughts

·        Would not be able to get nutrients AT ALL

·        Would not be able to survive whatsoever.