Soil and Vegetation Connections

Soil and Vegetation Connections Making Connections 2nd Ed. Page 170-171

Key Terms Can be obtained through the textbook glossary

2. a) how is topsoil formed?

Topsoil is formed very slowly as dead plants, leaves, and animals are decomposed by bacteria. The decaying organic materials form humus, which gives the topsoil its dark colour.

3. Why is the size of rock particles important to soil structure?

The larger rock particles of sand allow rainwater to drain quickly through the soil, while the smaller particles of clay prevent rapid drainage. A well-balanced mixture of both allows the soil to hold moisture, and at the same time allows water to pass through at a rate moderate enough to allow plants to take up nutrients.

4. Explain the difference between leaching and calcification.

 Leaching occurs in areas of high precipitation (creating wet-climate soils); calcification occurs in dry climate areas (creating dry-climate soils).  The leaching process is a downward movement of water through the soil; the calcification process is an upward movement of water through the soil.  As leaching occurs, water dissolves the chemical nutrients and carries them downward; as calcification occurs, water evaporates, leaving behind the minerals that were dissolved in it.  Leaching removes nutrients in the soil that plants need to survive; calcification builds up nutrients and minerals in the upper portion of the soil.  Excessive leaching results in a poor, often thin, topsoil layer; excessive calcification results in a layer of mineral deposits that is poisonous to plants. **Diagram was drawn on the board during the soil note.

6. There are two classes of trees. Which one can survive a harsher climate? Why?

Coniferous trees can survive in a harsher (colder) climate because they have the following characteristics:  Long roots are able to extract nutrients from the poor soil.  Sticky sap prevents the needles from freezing.  Waxy needles and thick bark prevent a loss of moisture in times of drought.  The needles and flexible branches easily shed snow to prevent damage.  The needles can conduct photosynthesis on warm days beyond the normal growing season.

7. Name the Canadian vegetation region which: a) Is the largest Boreal and Taiga forest region b) Is the smallest Deciduous forest region c) Is the wettest West Coast forest region d) Is the coldest Tundra region

8. Explain, in your own words, the term “transition zone.” Give an example and explain why this vegetation region is a transition zone.

Transition zone:  A transition zone is an area where the natural vegetation of one region gradually changes into the natural vegetation of another region.  A transition zone is the line on a map that shows the boundary between one vegetation region and another, but does not indicate and abrupt change in the natural vegetation.  A large transition zone is considered to be a vegetation region in itself.  A transition zone is the area where the climate and soil conditions of one region begin to change into the climate and soil conditions of another region.

Example: An example of a transition zone is the Mixed forest vegetation region. This region is located between the Boreal and Taiga forest region and the Deciduous forest regions. The Mixed forest vegetation region is a transition zone because it has the same type of natural vegetation, namely coniferous and deciduous forests, as the two regions that border it. In the northern part of the region the climate is similar to that of the Boreal and Taiga forest, while in the southern part of the region the climate is similar to that of the Deciduous forest. The soil in northern parts of this transition zone is similar to the leached, infertile soil of the Boreal and Taiga forest; in southern parts, it resembles the soil of the Deciduous.

12. “If you climb up a mountain, you will find a similar sequence of vegetation to that you would find if you travelled from southern Canada to the high Arctic.” Explain why this is a valid statement.

As you climb up a mountain, the temperature decreases. With every increase in altitude, the air becomes colder. The change in the mountains climate has a direct effect on the type of vegetation growing up the mountainside. The warmer temperatures at the bottom encourage the growth of deciduous and coniferous tress and the abundant groundcover in the form of grass, small plants, and shrubs. Higher up, the deciduous trees start to disappear because they cannot survive the colder temperatures. As the climate becomes even colder, the groundcover and shrubs begin to disappear. The coniferous trees begin to thin out, and gradually disappear. All that remains is moss, and very small plants growing between patches of bare rock. A snowcap sits on the very top of the mountain all year. As you travel from southern Canada to the high Arctic, the climate becomes colder. It affects the vegetation in the same way that an increasingly colder climate affects the vegetation growing up a mountainside. The weather in the Southeastern climate region of southern Canada is warm and we, and encourages the growth o deciduous and coniferous trees. The dry climate of the Prairies does not encourage the growth of trees, but the grass grows abundantly. North of the Prairies, the Boreal and Taiga forest region has climate conditions that are harsher than those in the Mixed forest and Grassland regions. These conditions prevent deciduous trees from growing, but the coniferous trees still survive. Farther north, where temperatures are even colder, the coniferous trees begin to thin out, until they gradually disappear. Above the tree line is the Tundra where only small shrubs, moss, and lichen grow close to the ground, between patches of bare rock. In Arctic areas of the Tundra, there is nothing but snow and ice. 13. Complete the chart Vegetation Types of Natural Temperature Precipitation Soil Characteristics Region Vegetation Characteristics Characteristics Tundra -Shrubs, mosses, lichens, -Cold, short -Very little -Thin soils, small flowers growing season precipitation, most permafrost areas les than 400mm Boreal and Taiga -Coniferous trees, e.g. -Cold temps -wet climate -very little humus Forest white and black spruce, -short growing -shallow topsoil balsam fir, pine season -grey-coloured (evergreens), which lose topsoil few needles -acidic -Hardy deciduous trees -rainfall and (poplar and white birch) snowmelts wash in southern portion away soluble minerals -leached soil -infertile and unsuitable for agriculture -few organisms such as bacteria and earthworms Mixed Forest -coniferous and -temperate climate -regular, abundant -deep, grey-brown deciduous trees (spruce, has warm summers topsoil rich in fir, pine, cedar, hemlock, and cool winters minerals maple, beech, ash, oak, -cold winds create -good supply of birch) a harsh climate humus -small shrubs, e.g. along the coast of -few soluble junipers along the coast the Maritime minerals are of the Maritime provinces removed from provinces topsoil by leaching -suitable for farming Deciduous Forest -deciduous trees -long, hot summers -plentiful -less acidic than (especially hardwood -minimum of five Mixed forest b/c of trees such as maple, months of warm greater number of beech, hickory, ash, black weather deciduous tress walnut) -relatively mild -more humus than winters Mixed forest -humus-rich topsoil is dark brown -some soluble minerals leached from topsoil by abundant rain -most fertile soil of eastern Canada Grassland -drought-resistant short -cold winters, hot -very dry -limited amount of -short grass grasses with root summers -limited rainfall humus systems which forms a -high evaporation -calcified soils sod mat -unsuitable for crops -sagebrush and cactus -suitable for grazing -trembling aspen, willow, cattle and other and spruce grown only in animals river valleys where enough moisture is available

-long grass -grains -oil seeds -large amounts of -long grass -cold winters, hot -dry humus that result in summers -increased precip rich black soil -just enough rainfall -richest soil in to keep the minerals Canada within easy reach of -produces some of -long grass dotted with the grass roots the best grains in the clumps of trees world -coniferous trees more common in the north -more precip than -transition soil -parkland -deciduous trees -cold winters, hot grassed area, but between the rich dominate in the south summers less than forested black soil of long area grass and the grey- coloured soil of the Boreal forest Cordilleran -vegetation varies greatly -warmer in the -heavier rainfall on -soils of all types Vegetation due to varying temps and valleys than high in the west side of -soils change precip the mountains mountains completely wihin a -grasses and catuses in -dry, hot valleys on -drier on the east short distance dry, hot valleys on the east side of side of mountains -soil type east side of mountains mountains -heavier determined by -coniferous forests on -temps get colder precipitation on elevation, slope, lower slopes where with elevation lower slopes rainfall, and veg precipitation is heavier -snow and ice on the cover -meadows of flowers and very highest slopes -in dry, hot valleys shrubs similar to Tundra on east side of veg on higher slopes mountains, soils are above tree line similar to those in -no veg on the very short grasslands highest slopes -irrigation is often required for agriculture -grey-coloured soils under coniferous forests -tundra soils and bare rock on higher slopes above tree line West Coast Forest -temperate rainforest -mild climate -heavy rainfall -lush veg provides a (lush forests of Douglas lot of plant material fir, Sitka spruce, red to make humus cedar, western hemlock) -minerals leached -trees more than 1m in deep into the soil diameter, and over 50m high