The life of a leaf is never easy. Our autumnal glory had its origin in the latent buds formed on the branches two summers ago. They sat waiting out the cold winter exposed to the ice, snow and frigid temperatures. As spring 2011 warmed the air and the sun’s rays shown on the naked branches our leaves began to wake. Slowly they swelled and woke up the physiological processes of the tree. Unfurling at a rate not too slow for us to enjoy, their life-giving duty to the tree began. I believe photosynthesis is the most important chemical process on Earth. Our leaves now are tasked with carrying out the exchange of CO2 and O2, providing complex sugars to the tree and driving the water uptake from the roots. This is no small assignment for such a delicate piece of Mother Nature’s beauty. Last summer’s prolonged dry spell and record setting consecutive days of at or near triple digit temperatures was more than some could handle. Those that the tree did not shed finally arrived to the welcoming rains of a very wet August. Before the tree can relinquish the army of leaves in the fall, they are asked for one more act. They must replenish the tree with all their stored up food supplies to get the tree through winter. While green chlorophyll exits the leaves it exposes the pigments that provide the stunning display of foliage. The anthocyanin and carotenoid pigments are presented to our amazement.
There is nothing better than watching the silver maple’s yellow leaves float playfully to the ground. It is a shame to disturb this elegant descent with the roar of the 100 dB (decibel) leaf vac truck. You’ll see and HEAR the Grounds and Arboretum crews clearing the leaves of the turf then sucking and shredding them as are taken to the composting site on campus.
The life of our leaf is long and arduous and has kept the majestic trees on campus healthy for another season.