Soil-Vegetation Connections in the Boreal Forest

Transcription

1 Soil-Vegetation Connections in the Boreal Forest Lesson Overview The boreal forest is identified as being a key ecosystem which contributes much to the world and Canada. Understanding its formation, role, fragility, resources, and maintenance will enable the nurturing of sound sustainable practices. This lesson involves two components. First, students will observe and measure a soil profile in the field. Next, they will analyze and interpret the profiles in the classroom. This process will enable students to make connections between soils and forest cover. Grade Level Grade 12 (secondary school) Time Required Two classes (One class in the field and one class for analysis and interpretation.) Curriculum Connection (Province/Territory and course) Atlantic Provinces Curriculum for Social Studies: Council of Atlantic Ministers of Education and Training (CAMET): Newfoundland and Labrador Canadian Geography 1202, Section 3.3 (This lesson should be used at the end of the unit, after students have learned about soil characteristics.) This lesson may be modified for any similar courses across Canada. It is also a good fit with the Higher Level IB Geography programme. Additional Resources, Materials and Equipment Required Soil profile images (attached) (use a computer to display or print copies) Forest Soil Profile Exercise (attached) Sample paint colour cards from building supply stores (or have students create their own markers) Student field notebooks and colour markers Main Objective To investigate the relationship between soil type and boreal forest vegetation cover. Learning Outcomes By the end of the lesson, students will be able to: perform basic observations on a soil profile; recognize differences between different types of soil profiles (podzolic and brunisolic soils) common in Newfoundland and Labrador and other Canadian boreal forests; assess the role of boreal forest trees and understory vegetation in soil development; recognize the interplay between soil, vegetation, and climate; appreciate the importance of sustainable forest management practices.

2 The Lesson Introduction (In class prior to field study) Lesson Development (In the field) Conclusion (In class) The Lesson Teacher Activity Show examples of boreal forest podzol and brunisol soils. (See Soil Profile images attached.) Encourage students to note their observations. Ensure students can define and differentiate colour varieties. Invite suggestions of how this can be overcome. Distribute copies of the Forest Soil Profile Exercise and ensure students are equipped with colour markers before embarking on field exercise. Assist students where applicable. Discuss with a focus on: Classification of the soil profile as a Podzol or Brunisol; How the soil type relates to the vegetation; What other detailed tests could be applied to better describe and categorize the soil and the vegetation. Student Activity Examine images and record examples. (Because perception of colour varies widely among people, this poses a problem, because colour is commonly used to describe and differentiate soil horizons.) Give strategies on how this problem can be overcome. (One method is to use the suggested paint colour samples.) By following instructions on the worksheet, investigate soil types and use standardized colour chips to compare soil horizons. (Regardless of how each investigator sees a particular shade of brown, if the soil horizon and the colour chip appear identical, then the colour can be accurately described.) Discuss field findings and formulate conclusions. Complete the questions on the worksheet.

3 Assessment of Student Learning Assess the Forest Soil Profile Exercise for completeness and accuracy. Further Reading Canadian Geographic/FPAC Boreal Forest poster-map Canadian Geographic/FPAC Boreal Forest interactive map Canadian Atlas Online Future of Forestry theme Forest Products Association of Canada Canadian System of Soil Classification, 1998 edition Link to Canadian National Geography Standards Essential Element #3: Physical Systems Components of Earth s physical system (atmosphere, lithosphere, biosphere, and hydrosphere) Geographic Skill #2: Acquiring Geographic Information Systematically locate and gather geographic information from a variety of primary and secondary sources.

4 Soil Profile Images Source: N.Catto

5 Above: Brunisolic Soil Profile Source: N. Catto Above: Podzol Soil Profile Source: N. Catto

6 Forest Soil Profile Exercise A: In the Field 1. Locate the soil profile on a map. 2. Indicate the aspect and position of the profile (e.g. faces north, at the top of a small hill) 3. Divide the profile into the horizons (e.g. Ae, Bf). 4. Draw a sketch of the profile, with each horizon labelled. 5. Measure the depth below the surface to which the deepest roots penetrate. 6. Describe each horizon in the soil profile by identifying the following features: a) thickness in cm b) colour c) texture (e.g. sand, sandy gravel) d) structure (e.g. granular, blocky) e) consistency (e.g. firm, loose) f) moisture content (e.g. wet, moist, dry) g) presence of mottles or gleying (yes or no; if yes, what colour) h) presence of charcoal fragments (yes or no) i) presence of iron oxide accumulations or crystals (yes or no) j) nature of the lower contact of the horizon (e.g. distinct, gradual; planar, undulating) 7. Describe the vegetation cover over the soil profile by noting: a) the tree species (include both mature trees and saplings) b) the understory vegetation c) the density (number of individual plants per unit area) for mature trees and saplings. Measure a 10-metre straight line; count the number of plants per linear metre; and then square the value to obtain an approximate density per square metre. Do separate calculations for mature trees and saplings. d) presence of fallen trees (yes or no) e) evidence of human cutting of trees (e.g. stumps; yes or no) f) evidence of animal activity (e.g. beaver gnawing; bark rubbing; browsing; yes or no) g) evidence of fire (charred trees, charcoal; yes or no)

7 B. At home or in class: 8. Classify the soil profile as a Podzol or Brunisol. Are there any features in the profile that are not typical for this soil type? 9. Does the boreal forest cover represent a mature forest, a forest undergoing regrowth, or one that has been disturbed by human activity? 10. Is there any evidence of fire? 11. List the soil forming processes occurring within the soil. 12. How does the soil type relate to the vegetation? 13. What other detailed tests could be applied to better describe and categorize the soil? 14. What other detailed tests could be applied to better describe and categorize the vegetation? C. Research and complete the following (Use point form): What Would happen if? trees were harvested and not replaced? higher temperatures due to climate change altered growth patterns in the boreal forest?