Light and Shade

Source: 

Adapted from the Taynish National Nature Reserve, Local Schools Pack (SNH) 

& Second Nature - Environmental Studies Teaching Pack - SNH & RSPB (available from the RSPB)

Time

60 minutes 

You will need

• notebooks & pencils
• an area of woodland with a dense canopy and one with an open canopy or open glade
• PE hoops or canes and string for sampling
• woodland plants sample guide (see downloads)
• light meter (optional)
• plant identification guides (optional)
• camera (optional)

Did you know?

Woodland flowers such as primroses and bluebells grow, flower and die back before the canopy of new leaves overhead blocks out most of their sunlight.

Before the Activity

Plan the activity with the children and ask them to design an experiment to compare the plants growing in the shade and the plants growing where there is more sunlight. They will need to consider:

Sample area, will they use a 1m² quadrat made from canes or a PE hoop?

Random sample or transect sample: Will they drop the sampling device in a randomly selected spot (throw backwards with their eyes closed?) or will they walk in a line between two points and sample at pre-decided intervals? Discuss fair testing.

What will they record: Will they record just the number of different kinds of plants (total number of species?) or will they record numbers in the different plant groups (the number of mosses, herbs, tree seedlings, grasses, lichens, rushes) separately? Will they try and identify the herbs and tree seedlings?

How will they record the light level? A description of the general area? By using a light meter? By looking directly up at the sky and estimating the percentage shading of the sky by the tree leaves?

Will they work in pairs or groups? How many samples will each group take? Why is sample size important?

Design a recording sheet. Is it important to record the date?  Why would you possibly record more plants in the spring time than in late summer in a deciduous wood?

The Activity

Gather the class together in an area of diverse woodland structure. (Discuss the dangers of Fungi – and that the children should not touch or take samples of these). Explain the difference between counting the number of, for example, daisy plants, and counting the number of different plant species. If the grasses are not flowering they still may be able to tell different grasses apart by feeling the softness of the leaves and comparing the size of the leaves. Rushes, sedges and grasses are difficult to tell apart but rushes have a hollow round stem and sedges are triangular in cross section. Point out the main types of mosses which are easy to see and encourage the groups to take a really close look at ground level in the sampling points to try and discover small creeping plants and other mosses. They may also encounter ferns, lichens and fungi and be ready to help them distinguish between these plants as they discover them.

Once the sampling and recording is complete, gather the groups together again. See if they can answer the following questions:

• Why do light levels vary? (factors include: tree type, distance between trees, type of tree leaves, canopy height)
• Do some plants only grow in shaded or open areas?
• Are tree seedlings found in shaded or open areas?

Suggested Follow up

• Carry out the activity Useful Plants in the People Section 
• Back in class, draw bar charts to represent plant diversity in the two areas sampled. What conclusions can be drawn?
  

Downloads

• woodland plants 1
• Woodland plants 2
• Plant groups - information sheet
  

Additional Information

Spotters Guide to Wildflowers (Usborne) - easy to use guide which includes many of the commoner plants

Curriculum Links

Science (main)

Age Range

2, 3