Tuesday, January 29, 2013

Tree Planting and Drought

The impact of drought on trees has been in the news quite a bit lately including this story from USA Today. Which begs the question: since we are in the midst of a severe drought and since there is no way to know how long this drought may last, should we be planting trees? That is a very fair question, especially if we think about the potential issue of water scarcity. If it came down to a choice between planting new trees or trying to keep alive the ones we already have, then I would choose the latter. But I don't think that is a fair assessment ofthe situation. My hunch is we can do both - and indeed we must  do both.

Dead Ginkgo in Waverly
Something that can help inform our decision making today regarding tree planting in drought is to look back at the 1930s, when some of the hottest and driest years on record were recorded for this part of the world. Just think about this: on July 25th 1936, Lincoln reached a high of 116 F and the overnight low was only 91F - yikes! Back then the fear of drought and a changing climate actually spurred huge efforts at tree planting across much of the central US. In fact the Prairie States Forestry Project led to the planting of more than 220 million trees in shelterbelts and other plantings across the region. People realized the great value trees provided in taking the edge off the often brutal Great Plains climate.

Although I have come to love the wide-open expanse of this part of the world and feel we should do much more to conserve our prairie heritage, I would not want to live in a community without trees. They are vital to making our communities more comfortable, livable and beautiful. So I say yes! Let's plant more trees, even during times of drought. Our community forests are ever-changing and dynamic and require our constant attention at planting and care. With a changing climate that will almost certainly include more droughts and likely higher overall temperatures, it should be obvious to all of us that we need to adopt the best practices possible when it comes to tree selection, planting and care. A few suggestions that I would offer to help our tree planting endeavors would include:

1. Emphasize the planting of species that have proven drought survivability including bur oak, gambel oak, hackberry, juniper, Ponderosa pine, Osage orange, green ash, walnut, elm, etc. (Note: yes I did intend to include green ash here. Although we don't recommend the species for wide-spread planting due to the threat from emerald ash borer, the advancement of the pest across the region is relatively slow and many green ash trees will likely be alive for decades to come - especially in the western half of Nebraska).
Walnut is drought tolerant

2. Plant high quality root systems. Roots should be fibrous and laterally spreading, not circling at the bottom of a container.
3. Plant smaller trees more often. There are several factors at play here, but in general smaller nursery trees with good root systems are easier to establish in the landscape and generally become drought tolerant more quickly than larger specimens. There is nothing wrong with planting seedlings or even seeds, as long as those small plants can be protected in the landscape.
4. Plant properly! The first trees to die in any drought are the ones whose health was compromised for some reason. Common compromisers to good health in landscape trees include problematic roots and trees planted too deep.
5. Group trees together and encourage a healthy rooting zone. Trees grouped relatively close together help protect each other from weather extremes. And if the space between trees is maintained as nutrient recycling system with appropriate groundcover plants or mulch (not intensively managed turfgrass) the soil and rooting zone will be much better at conserving moisture and much healthier for the tree.
Planting a seedling can be good strategy.

For those who like Facebook, ReTree Nebraska is a good place to go for good tree spirit:


2 comments:

  1. This is a great post. Also a helpful article. We also doing such type of job in PlantWerkZ site. Because trees are our best friends.

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  2. Justin, these are all great tips! Thank you very much. By the way, do you have a garden? Can you share it to us? With that knowledge in planting, surely you have a beautiful garden.

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