The Nutrient Cycle - Soil: Reflections on the Basis of our Existence - page 86

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Recycling workers . Decomposer saprotrophic fungi are quickly in place and grow their myce-
lia to break down withered leaves. Here ( top photo ) mycelia have grown out from a thin twig.
Fungal spores on the surface are ready to grow when the leaf dies. Some fungi grow in living
leaves without damaging the plant, ensuring they are first on the scene when the leaf dies. Many
different kinds of fungi together break down leaves in the rainforest. The middle photo shows
a pyrenomycete, a relative of the stag's horn fungus that grows on dead tree-stumps in Europe.
Its antennae-like fruit bodies facilitate spore dispersal. The thin leaf ( lower image ) contains suf-
ficient energy for the fungus to build a forest of pin-like fruit bodies. The spores spread to new
leaves and the fungus can live on while the cycle of growth and decomposition continues

Everywhere I looked, empty pods or chewed fruit dotted the forest floor, signal-
ling the presence of monkeys. A thin layer of brown leaves covered the ground.
Hold the leaves to your face and a full-bodied mushroomy smell hits your nostrils.
The leaves do not have time to build up on the forest floor because the heat and
humidity create a rapid decomposition process of just a few weeks. Indeed, we did
not see any ground layer of organic matter anywhere in the jungle. Beneath the
leaves lay a tight blanket of delicate tree roots colonised by mycorrhizal fungi that
absorb the nutrients of decomposing leaves. The soil beneath lacks sufficient nutri-
ents to support the plants and trees by itself and relies on the continuous addition
of leaf litter. When rainforest is clear-felled the nutrients quickly disappear and the
soil can only support a few harvests before becoming too depleted for farming. It
takes a long time for such soil to become fertile again.

An unknown beauty . The rainforest contains many species not yet known to science. The unusual
structure on the right of the photo remains unexplained, though I have consulted several experts
in tropical mycology. Probably it is a kind of vegetative propagation organ that lies on the ground
waiting for organic matter to fall from the trees