Not so dead woodBittu SahgalIn the next few months I will be interacting with hundreds of teachers throughout India and through them with over 1,000,000 children across the country. This is under the aegis of the Kids for Tigers, the nature education programme that is helping to transform teachers and students into India‚s most effective Green Army.In our mission we have the support of Pradeep Poddar, CEO of Heinz India Ltd, makers of Complan, our sponsors. With his entire team, he shares our belief that in this day and age no child‚s education can be considered complete unless she is provided a real sense of what it takes to protect her natural heritage.Of course, clued-up contemporary teachers constantly remind their students how important trees are. Which is just as well, because they are among the least appreciated of nature‚s masterpieces. Indeed it‚s difficult to imagine a more useful ‚Ëœinvention‚. We need oxygen, which trees give us. And we put out carbon dioxide ‚ tonnes of it ‚ as our ‚Ëœwaste product‚, which trees transform into all manner of resources including food and fuel. No man-made machine could perform this vital service for us half as well. Indeed, almost everyone interested in environment and the great outdoors loves trees. Trees have beauty and grace that few other life forms can match. But when a tree falls, it is at best regarded a dead asset. This, I always take pains to explain to teachers, is a mistake. I suggest to them instead, that their wards are introduced to the miracles that allow even a dead tree to provide shelter and life to uncounted other life forms.In the course of its life (and this varies greatly from species to species) a tree works as a collector, retainer and converter ‚ all rolled into one. Water, solar energy, soil and minerals are all absorbed and retained by trees to be converted into leaves, wood, sap, flowers and fruit.Nutrients are thus blocked in a living tree and admirably protected by the tree‚s natural defences. The outer bark, for instance, prevents all types of invading organisms from attacking and destroying inner wood tissues.But once a tree dies, the dry, strong, hardy bark that used to function as a protective layer, begins to weaken. Why? Possibly because of fire, moisture in the atmosphere, or perhaps wind erosion. To a greater or lesser degree all these contribute to the inner tissues ‚ xylem and phloem ‚ losing their firmness. And this, ironically, is the trigger for new life forms to manifest themselves in the logs of a dead tree.Though you could find plenty of fungi on the stem of a tree even before it has fallen, it is only when the tree is well and truly dead that the fungi and mosses actually flourish. This is when the ‚Ëœinvasion‚ really begins. Organisms that enter new habitats (in this case the fallen log) are loosely termed invaders. The ecological term for this sequence of colonisation is ‚Ëœsuccession‚.Look in your neighbourhood for an old tree. Here you should easily discover a large fallen branch. Search and you will find, apart from fungi and mosses, engravings and narrow tunnels in places, particularly where the bark has been stripped and exposed. This is the work of engraver and wood-boring beetles, termites and other insects. A simple task teachers can ask their wards to perform is to count all the different species of beetles and insects they can locate. At first glance, they may be disappointed to see nothing at all. But wait. Gently prod a rotting log or pull off a little strip of the loose bark and tiny creepy crawlies will start scuttling about. This is a good way to discover insects and other small occupants (take care not to damage their handicraft!). Besides beetles and termites, wood ants, field crickets, moths and perhaps a wasp‚s nest, you might find arthropods such as centipedes and scorpions; even a frog or a toad may hop away from somewhere near the log.A lot of what you might see will depend upon the nature of the wood, and where it lies. Your best chance of seeing numerous life forms is in moist, decaying logs. Some, you can point out to your students, tend to bore deep into the wood, while others remain only in the outer tissues; some insects and organisms spend their entire lives in decaying wood, and create the most amazing patterns of tunnels and galleries therein. If you are a careful and regular observer, you will be witness to a small food chain that may already have formed in the immediate vicinity of the log. The cavities and tunnels drilled by beetles and termites become pathways or entry-points for predators, including large insectivores, small lizards and birds such as the woodpecker and tree creeper. Ultimately, of course, the number and species will depend upon the habitat and the time of year. Ask your students to keep a ‚Ëœlog-log‚ (record) of all the birds and insects they see and a regular classroom project will emerge. With the passage of weeks and months, the log will decay and soften further. The holes and crevices will enlarge. With luck, a hole-nesting bird may breed in the tree. Snails will crawl around, perhaps even a small snake (leave it alone, it is merely performing a pest control service for the neighbourhood).Dead wood provides micro-habitats which fascinate biologists and botanists. Its decomposition helps saplings/ seedlings grow. Eventually the log will be returned to the earth as soil-enriching humus ‚ the very stuff of diversity. So when you next come across a fallen tree, treat it as a valuable resource. It might prove to be your key to teaching children how to care about the secrets of the earth.Log on to www.kidsfortigers.org for more ideas on how teachers can help turn children into defenders of Mother Earth.(Bittu Sahgal is the editor of Sanctuary magazine)