A Prairie Garden Journal    by Dick Meyer

Hot Tips for Planting Cooling Trees

Global warming or global climate change.  It may turn out to be the single biggest problem ever faced collectively by human civilization.  Its likely causes are so imbedded in the fabric of human society and economy that the kind of rapid change required to quickly reverse the problem is unlikely.  Until recently there was far more effort being spent on measuring and defining the problem than on proposing solutions.  Earth Day 2007 is seeing the beginning of a significant public discussion of both short term and long term solutions. 

Regular readers of this column will remember that I am not a particular fan of planting trees for trees sake in Wyobraska.   The fundamental nature of our indigenous landscape is sun-washed open prairie dotted by occasional tree-lined ridges.   Planting trees everywhere would change Wyobraska’s landscape from prairie to forest—a sacrifice that we don’t need to make just in order to save the planet.   Besides that it most likely wouldn’t work because the region doesn’t receive enough natural precipitation to support a forest—our 10-15 inches of average rainfall is the main reason that the Wyobraska region is a prairie in the first place.

Each tree will help save our soils, keep our freshwater fresh, absorb carbon dioxide from the atmosphere, and encourage other plant and animal life… making the world a better place.

Previous Articles

Fractions March 15
Yardner March 8
Urban Legends of Trees March 22
Que Serra, Serra March 29
Grocery Store or Garbage Dumpster Plants April 5
Planning Your Landscape Project April 12

2006 Articles

Thirty-something years after the founding of Earth Day, the celebration created to remind us of the biological wonders and mysteries of our blue-green planet is being retooled to raise public awareness about global climate change—its causes, likely long-term effects, and actions that we mere humans can take to help reduce and/or solve the problem.   While there is not yet universal agreement about the issue, one point on which virtually everyone agrees is that human economic activity is dramatically increasing the concentration of carbon dioxide in our planet’s atmosphere.  And virtually everyone agrees that the cause is the burning of fossil fuels in cars, trucks, and coal burning power plants. 

So one of many constructive solutions being proposed to the problem of rising levels of carbon dioxide in the atmosphere is to plants trees.  Consider these statistics offered by the United Nations Billion Tree Campaign: 

• In one year an average tree produces enough oxygen for a family of four for one year.
   
• One tree will absorb the CO2 from 4 cars every year.
   
• Planting trees remains the cheapest, most effective means of drawing excess CO2 from the atmosphere.
   
• To make up for the loss of trees in just the past decade, we would need to replant 321 million acres, which would entail planting 14 billion trees every year—for ten consecutive years.

The website of the United Nations Billion Tree Program offers additional insights about the loss of the planet’s forests over the past 10,000 years as a result of agriculture and other human activity, and about the ways we can begin to reverse that trend.  I suggest a visit to the site by anyone interested in the issue.

But there are certainly ways that we Wyobraskans can do our fair share of the United Nations Billion Tree Campaign.  Following are some hot tips about how and where to plant cooling trees in Wyobraska.

First, plant well adapted tree species.   Poorly adapted trees tend to grow slowly and rarely become the large mature tree that will lock up CO2 in its tissues.  So stick with proven species for your Cool Trees.  I suggest the following varieties:  bur oak, ponderosa pine, rocky mountain juniper, limber pine, American linden, littleleaf linden, Kentucky coffeetree, catalpa, ohio buckeye, or honeylocust. 

Second, plant trees where they will receive adequate natural precipitation or supplemental irrigation in order to grow to maturity.  The evergreen trees listed above are mostly able to survive on the region’s natural precipitation—although some supplemental irrigation until they are established is helpful.  The deciduous trees are better planted either in irrigated landscape settings or in non-landscape settings with some for of supplemental irrigation.

Planting strategically located shade trees in our residential and commercial helps in two ways.  It reduces the energy required to cool our homes in summertime, while locking up carbon released to generate the electricity to run the air conditioner.  This can be done without turning our residential landscapes into shade gardens by planting shading trees closer to buildings rather than out in the middle of the landscape.

Use evergreen trees for screening plantings and as landscape fillers to reduce the amount of irrigated lawn.  The green winter color of evergreens helps to add interest to our long-lasting winter season, again, while locking up carbon. 

Many residential lots are large enough to accommodate a “mini-forest”—a grouping of shade trees or evergreen trees planted in a mulched island.  It’s a great way to reduce the amount of irrigated turfgrass, too.   By the way, when trees are planted in mulched islands, they also have a much greater chance of becoming the large trees that tie up carbon for long periods of time.  The reason is that a mulched island creates the kind of soil ecosystem that most trees either prefer or require for healthy growth.

I like to look at it this way—when scientists, oil company executives, conservative politicians, and liberal environmentalists all agree on something, it’s probably a good idea.  Happy Earth Day 2007.