Teacher guide reSolve: Tree Biomass

TLF ID M025325

In this sequence of two lessons, students investigate how many trees would be required to supply paper for their school for a year. Students use similar triangles, Pythagoras' Theorem and algebra to design and construct a Biltmore stick, used to measure the diameter and height of a tree. They measure trees, calculate their volume and use the density of the tree to find the dry mass of the tree. They estimate the amount of paper used in the school and hence estimate the number of trees that need to be cut down to supply the school's paper needs. The lessons are outlined in detail including curriculum links, vocabulary, sample answers, discussion points and student resources. This sequence is part of the reSolve: Maths by Inquiry program.

Educational details

Educational value
  • This resource is very valuable for the year 9 mathematics content descriptions about investigating Pythagoras' Theorem and using ratio and scale factors in similar figures to solving simple problems. In the first lesson, students use scale factors and similar triangles to determine the height of a tree. They also use Pythagoras' Theorem and similar triangles to measure the diameter of a tree, using a device called a Biltmore stick.
  • The resource is also valuable for the year 9 mathematics content description about calculating the volume of cylinders and solving related problems. During the sequence, students calculate the volume of a cylinder and its density to determine the volume and hence mass of a tree, and therefore the amount of paper that a tree could provide.
  • This resource also offers opportunities to link to the Numeracy General capability, as they estimate and measure with metric units and solve complex problems involving the volume of prisms and cylinders, in order to estimate how much paper could be obtained from a tree.
  • This resource is also of pedagogical value as it supports teachers in building an inquiry-focused learning environment with authentic application of mathematical skills and understandings. The unit aims to develop content knowledge as well as assisting students to understand the process of inquiry.
Year level


Other details

  • Contributor
  • Name: Education Services Australia
  • Organization: Education Services Australia
  • Description: Data manager
  • Address: VIC, AUSTRALIA
  • URL: http://www.esa.edu.au/
  • Copyright Holder
  • Name: Australian Government Department of Education and Training
  • Organization: Australian Government Department of Education and Training
  • Publisher
  • Name: Australian Academy of Science
  • Organization: Australian Academy of Science
  • Description: Publisher
  • URL: https://www.science.org.au/
  • Resource metadata contributed by
  • Name: Education Services Australia Ltd
  • Organisation: Education Services Australia Ltd
  • Address: AUSTRALIA
  • URL: www.esa.edu.au
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Learning Resource Type
  • Online
  • © Australian Government Department of Education and Training 2017. Unless otherwise indicated, this material may be used in accordance with the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.