91�ȱ�

Narrator:
For this investigation, each group will need chalk, string, scissors, measuring tape, a student recording sheet, pens, a 30cm ruler, plastic wallets, labels, a tree identification sheet, and a carbon calculator sheet. Before you begin the investigation, you should consider, is the area around the tree clear from obstacles, such as bushes, bins and bollards? Is the area around the tree asafe distance from roads? Are the trunks easy to access? Please refer to the lesson plan for guidance. Use chalk to number each tree in the area you are going to survey. Divide the class into small groups, and allocate each group one of more trees to investigate. Each group should note down the number of the tree they are surveying. Part one, measure the circumference. Use thechalk to mark one side of your tree 130cm from the bottom of the trunk. Mark the other side of your tree at the same height. Hold one end of the string against the first chalk mark. Wrap the string tightly around your tree. Make sure it passes along the second chalk mark. Mark the string where it meets. Measure the length of your string from the end to the mark. This is thecircumference. Part two, measure the height. Pupil one should stand facing the tree and hold up the ruler at arms length, with the 30cm mark at the top. With the help of pupil two, pupil one walks carefully backwards, looking through the ruler, until they can see the top of the tree as in line with the 30cm mark, and the bottom of the tree trunk is level with 0cm mark. It's importantpupil one holds this position with the ruler at arms length for the next few steps. Pupil three stands next to the tree and points their hand at the side of the tree near the ground. Guided by pupil one, pupil three moves their hand until it is level with the 3cm line on the ruler. Mark the tree at this height. Measure the height of the new mark. Multiply this measurement by ten to getthe height of the tree. Collect evidence to identify your tree. This could be leaves, fruit, seeds, buds, flowers, or a photograph. Label the evidence with the tree's number and your names. Repeat this process for every tree that you survey. Pupils should wash their hands afterwards. Part three, find out your results. Use the tree identification sheets, alongside your evidence, toclassify the trees you have surveyed. You can now use the appropriate carbon calculator worksheet and your data to work out the carbon value of each tree. Collate all the pupils' results to work out the total carbon value of the trees in your survey. Refer to the lesson plan for guidance.