Trees come in all sorts of different shapes and sizes. There is an incredible diversity of tree species around the world. In Canada, there are about 180 species of trees as well as about 5 000 other plant species in almost 400 million hectares of forested and tree covered land – all a part of the ecosystem that provide habitats for an estimated 140 000 species of animals, plants and microorganisms. The two categories of trees are known as coniferous and deciduous.
Coniferous (sometimes called evergreen, see information box below) trees grow upward rather than outward and have a triangular shape. This makes the conifer tree strong and keeps its branches from breaking under the weight of snow. The leaves on a coniferous tree are either long, pointed needles or are small, flat scales. The needles or scales will stay on the tree for several years and fall off gradually.
Seeds of coniferous trees and shrubs grow in cones. When a cone opens its scales, the seeds fall out. There are over 500 species of conifers and include the largest (redwoods) and oldest (bristlecone pines) living things. Canada has 34 different species of conifers.
Common examples of conifers are firs, spruces and pines and they can be identified by their needles. The firs have short needles with blunt tips. Spruces have four-sided needles that are very sharp and pines have needles that grow in bunches, wrapped together at the base.
Broadleaved deciduous tree in the fall.
Deciduous trees spread out as they grow and have a more rounded shape than the coniferous trees. Two common examples of deciduous trees are oaks and maples. Deciduous trees have broad, flat leaves that catch a lot of light but cannot survive without warmth and water.
In Canada, when summer ends and winter approaches, the leaves of deciduous trees die because the weather is not warm enough for the leaves to survive. This is when we see them turn brilliant red, fiery orange, shimmering yellow, gold and brown every autumn before they fall to the ground.
When the leaves are gone, trees can no longer produce food and so they stop growing during the winter months. Once the temperatures rise in the springtime and there is enough rainfall, tree buds sprout leaves once more and the tree begins to grow again.
The seeds of most deciduous trees are protected by a hard nutshell or fleshy fruit. The seeds are dispersed when the fruits or nuts are eaten by animals. Since the seeds inside the fruit or shell are not digestible, the animal eventually passes them through its droppings often away from the parent tree. This increases the chance for a seedling to grow in an area that is not shadowed by its parent.
Which is which? Are coniferous trees the same as evergreen trees? Most coniferous trees are evergreens, but some deciduous trees are evergreens as well. Evergreen trees keep their leaves in all seasons and lose them gradually. However, some broad, flat-leaved deciduous trees in the south also keep their leaves year-round. So, there you have it! Most coniferous and some deciduous trees are evergreens.