Trees and Forest Review

Trees and forests are valued for a number of reasons:

• Forests serve as a habitat for a variety of living things (animals and plants)
• Forests are important to humans for recreation (camping, hiking),
• We get raw materials (wood, fruit) from trees
• Forests provide jobs (forest ranger, loggers)
• Forests create a life-supporting environment ( provide food, provides oxygen and exchanges carbon dioxide)

The difference between plants and trees:

Trees	Plants
¨     Are perennials ¨     Are tall ¨     Made of woody materials ¨     Have leaves or needles ¨     Produce  flowers, fruits or seeds	¨     Are perennials, annuals or bi-annuals ¨     Have a stem ¨     Are woody or non-woody ¨     Have leaves ¨     Produce  flowers fruit or seeds

Trees and forests are affected by the living parts of the forest environment (biotic) and the non-living parts of the environment (the abiotic).  Some examples are: 

Biotic: plants, animals and microorganisms

Abiotic: sunlight, climate, rocks, water, wind and soil

There are many different types of plants and animals that live in the forest.   These include:

• Producers (plants)
• Consumers
• Decomposers 

All of these plants and animals interact to create food chains and food webs.

The nutrient cycle shows how nutrients flow throughout an ecosystem.  The nutrient cycle starts with the producer and ends with the decomposers.

Common decomposers include:

• Fungus- they lack roots, stems and leaves and cannot photosynthesis.  Some examples are rusts, mildews, mushrooms, conks, yeasts, molds
• Conks- are a special type of fungus attached to tree trunks.  They are very hard and look like steps on the trunk of a tree
• Lichens- are made up of two plants- a fungus and an algae.  The fungus absorbs water and the algae produce food because it can photosynthesize. 

The water cycle describes how water moves through the forest ecosystem.  Some points to the water cycle are:

• Plants need water to live. 
• Plants lose water through transpiration from their leaves
• Plants take up water from their roots.
• All water in an ecosystem is recycled- water goes into soil (precipitation), taken up by trees, given off by trees (transpiration), goes into the air as water vapor, condenses in the air and falls as precipitation.

If one part of an ecosystem is threatened or does not function, the rest of the forest ecosystem is affected

Example: If a forest is clear-cut, the soil will loose valuable nutrients.  It will run off into a river if there is a heavy rain because nothing is able to keep the soil anchored.  The stream may become full of silt and affect the fish and insects that use the river.  The animals (consumers) that had used the forest before it was clear-cut will have to find new sources of food and protection.

Trees and plants produce oxygen and sugars in a process called photosynthesis.  The trees take in carbon dioxide, water and energy from the sun and produce oxygen and sugar.  Photosynthesis takes place in the leaves.

Trees can be classified into 2 main types- coniferous and deciduous.

Deciduous trees	Coniferous trees
Lose their leaves every fall Often produce flowers and fruit Broad leaves Examples native to Alberta include the aspen and  poplar	Do not lose leaves in fall Cone bearing trees Needle leaves Example native to Alberta include the Lodgepole pine and jack-pine

To classify trees, we can look at several different characteristics.  A dichotomous key (classification key) can help us to find the name of the tree.

To classify leaves, we can look at:

• Leaf shape
• Margins
• Leaf arrangement
• Leaf type

To classify bark, we can look at

• Color
• Texture
• Pattern

We can classify trees by their general shape or silhouette.

We can look at the growth patterns of a tree by looking at tree cookies.  We can look at the pattern of the rings and determine:

• Differences in coloration and texture of new growth and old growth
• If scars are present from fire or mechanical damage (very dark area)
• If enough nutrients were present (nice even ring growth)
• If nutrients were not present (close together ring growth)
• Crowed conditions (close together ring growth)
• Trauma damage (smaller lighter scars) from torn branches or bark
• Evenness of rings (roundness) indicating that it didn’t grow on a slope or wasn’t leaning in any way.

Humans have used the forest in a number of ways in the past and present and will in the future.  These have included logging, recreation and might include some new future use.

Humans have enhanced the forest through protection of areas (National and Provincial parks) and have set up laws that protect animals and plants in the forest.

Humans have threatened the forests by over logging, cutting down areas for new house construction, and not taking care of the forest when using it for recreation.