Thursday, November 13, 2008

Falling leaves; changing climate

Cool weather in the fall causes the witch hazel to blossom. Below is same tree a few days earlier.

November 13, 2008 Middle Tennessee, @ 2:45 p.m.

I have been thinking about this moment for many days. I've been waiting for all the leaves to fall so that I can rake them for compost and then mulch my gardens with pine straw for the winter. It's finally happened. Both my cherry tree and my witch hazel have shed all but a few of their leaves. Both trees are surrounded by garden plots and their leaves just keep building up in them. I have other trees which are still hanging on to their leaves: a young elm tree is as green as ever; a Japanese maple has changed colors but the leaves have not yet fallen. Another tree, a parrotia, is changing colors but holding fast to its leaves.

Other trees in our condominium neighborhood are doing their own thing. Most tulip trees are still full and golden; the Bradford pears are about half and half.

Have you ever noticed the fallen leaves of Bradford pears? Each one is an exquisite original design with prints of the leaves smaller and of different shades nesting one within it.

This has been a long and pleasant fall. Election day (Nov. 5) weather here was perfect. And in Chicago where President-elect Barack Obama gave his victory speech to huge crowds in Grant Park, the weather was unbelievably warm. Two or three days later a Chicago friend reported the temperature dropped 36 degrees. That's more like Chicago weather for this time of year.

Despite several very cold days here, the temperature is back up so that I was very comfortable outside wearing a light sweater. I keep thinking its too late to plant a crop of winter greens but maybe not if I hurry.

All this leads me to think about global warming. Albert Bates who teaches permaculture at the Ecovillage Training Center has said that warmer weather is moving further and further north. He thinks that planting trees and protecting those we have is a necessary strategy to reduce the impact of climate change. He is not alone in that theory. Albert also says that we need to start figuring out which trees (and other plants) will thrive in the changing weather conditions as warmer temperatures creep northward. Succession, in which different species take hold according to environmental changes, is usually a gradual process but since the earth is warming so fast, comparatively speaking, we need to help Nature adapt by purposefully planting adaptable species. One way we can figure this out is to look at ecosystems to the south of where we are.

We can also become more observant of the nature around us and take some notes. I think tulip trees which are well entrenched in this part of Middle Tennessee will be here for a while because they survive unpredictable late frosts well. How can I tell? Striplings killed by frost bounce back as trees with two or three main trunks.