Lifespan

Annuals: one growing season; biennials: two growing seasons; perennials: many growing seasons. As gardeners, we know what to expect from our plants. Trees? Trees live forever, right? Nope. The fact that a tree may outlive a human is not disputed. There are dozens of ancient historical oak trees (Quercus spp.) that are several hundreds of years old, the “General Sherman” giant sequoia (Sequoiadendron giganteum) is nearly 3,000 years old, and “Methuselah” is a Great Basin Bristlecone Pine (Pinus longaeva) aged at more then 4,800 years and according to Wikipedia, is the oldest living organism on the planet.

With all those ancients in mind, I understand why we are perplexed when a tree dies. Especially when it is a relatively young tree. My colleague Kathy Thomas-Rico wrote recently about the death of European white birch trees (Betula pendula) in Vacaville. (“Birch Issues,” Under the Solano Sun, 9-2-11). It hit home this summer, right in our front yard. Our birch began to look less leafy than normal and subsequently died. Our tree  was one of many planted by the developer that built the homes on our street. Over the last sixteen years our tree grew to about thirty feet tall and except for nearly all the branches being on one side due to the prevailing Solano wind, it seemed healthy. I have since learned that the European white birch is not suited to our growing zone, which is too dry and too hot. It is even considered a weed by the U.S. Forest Service - one gardener’s shade is another’s invasive species!

Over the last few years we have watched the birches disappear one-by-one from the neighborhood. I am sad our pretty white birch has been reduced to little more than a perch for the wild birds, which is still a pleasant purpose, just not the intended one. But it serves as a reminder that trees have a lifespan.

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