A tree's roots absorb water and nutrients from the soil, store sugar and anchor the tree upright in the ground. All trees have lateral roots that branch into smaller and smaller roots and usually extend horizontally well beyond the branch tips; large trees typically have roots extending 20-40 metres or more from the trunk. The vast majority of the root system is located in the upper 10–30 cm of soil because the oxygen that roots require to function properly is most abundant there. In waterlogged soil with no oxygen penetration, none of the roots may be deeper than 10 cm. Exceptionally, a few trees in desert areas may have roots that reach down as far as 10 metres. Each root is covered with thousands of root hairs that make it easier to soak up water and dissolved minerals from the soil.
Trunk/StemEditThe trunk, or stem, of a tree supports the crown and gives the tree its shape and strength. The trunk consists of four layers of tissue. These layers contain a network of tubes that runs between the roots and the leaves and acts as the central plumbing system for the tree. These tubes carry water and minerals up from the roots to the leaves, and they carry sugar down from the leaves to the branches, trunk and roots.
The trunk of a tree, which is protected by a tough outer covering of bark, connects the roots to the branches and transports water and minerals from the soil to the rest of the tree. The trunk supports the tree and as it grows taller than the plants around it, it is able to reach more sunlight, which is essential for growth.
Branches, leaves and twigsEdit
Branches connect the trunk to the leaves and transport water and minerals to the leaves. The leaves, which are held up by branches, are arranged in a way that captures maximum sunlight. The tips of branches are known as twigs and these are the growing ends of the tree. Leaves grow on the twigs and produce food for the whole tree, but can only do this in sunlight.