Climate Change exists. We all know it, and we pretty much agree that the weather is not like it used to be. The climate is changing. This is obvious to anyone who is paying attention to the weather locally or globally. Why this is happening, how to stop it, and how to reverse it (if that is even possible) is an issue on which people do not agree. There are a lot of theories, and many from both sides of the argument will provide proof, but there is still a lot of disagreement. The two opposing views are:
(1) It’s human-induced climate change based on excess carbon release into the environment.
(2) It’s the natural, normal cycles of heating and cooling of the Earth.

I think it is much more complicated than one side or the other would claim, and the cause likely consists of normal Earth cycles combined with massive deforestation and significant pollution of our land, water, and air. With that said, in relation to this article, I don’t really care what is causing it.

Let’s pretend we are doing everything we can to stop climate change, and move on from there for a few minutes.

The Changes in the Arbor Day Foundation Hardiness Zones.

The Changes in the Arbor Day Foundation Hardiness Zones.

We can look at maps showing the shift of hardiness zones across the United States over the past decades. We can do the same for many other countries as well. We see two things: Winters are getting warmer, and Winters are getting shorter.

What does this mean for Permaculturist and Permaculture Designers? In Permaculture, we must answer the following questions for each project, and if we can’t give a good answer, maybe we shouldn’t do it:

  • What is our motivation for doing this? (Permaculture Ethics)
  • What things are we going to use? (Design Elements)
  • How are we going to use it or install it? (Technique)
  • Where are we going to use it? (Design)
  • When are we going to do it? (Strategy)
  • How is this going to change over time? (Succession)

It is succession that I am talking about today. We need to be forward thinking when it comes to climate change. We need to be proactive in how we choose plants for our land. We need to design for the future, both short and long-term. What do we have planned for next year? What about 5 years from now? 20 year? 50 years? 100 years? 500 years?

If we are not considering this in our Permaculture Designs, then we are not taking to heart Permaculture’s Prime Directive: The only ethical decision is to take responsibility for own existence and that of our children.

Forecasted changes in Hardiness Zones.

Forecasted changes in Hardiness Zones.

Okay, so what does this have to do with climate change? Well, when a person typically plants a tree, they choose a tree species that will grow well in their area… an apple tree, for instance. Then most people go to the local big-box hardware store’s nursery department and choose from the one or two varieties of apple tree there. If a person is a bit more horticulturally minded, they will go to a local nursery and choose from a greater variety of likely healthier trees. If a person is very horticulturally minded, and this is what the big-box stores and local nurseries are trying to do for us, they will find a variety of apple tree that is well-suited to the local growing conditions.

A big part of selecting a variety of apple tree “well-suited to the local growing conditions” is determining the USDA Hardiness Zone (or equivalent Hardiness Zone for the other parts of the world) and the Chilling Hours in a location. Briefly, the USDA Hardiness Zone Map divides the U.S. into Zones 1 through 10 based on minimum temperatures (1 being the coldest and 10 being the warmest). The Chilling Hours or Units are the number of hours below freezing temperatures (32F or 0C), or sometimes below 45F or 7C, which a plant needs to be dormant in order to produce a large number of flowers, and therefore fruit, during the next growing season. If you click on the links, I have full articles on each of these topics.

Most people, and nurseries, select varieties of apple trees (or any fruiting tree) that will withstand the Winter and will be cold enough, for long enough, to produce a good crop. Herein lies the problem. They are selecting varieties that are suited to climactic conditions as they are right now. In reality, the temperature data used to determine the best variety selection of a specific plant for a certain region is likely five to ten years old, maybe more. It takes an average of 3-8 years for an apple tree to start fruiting, and it will take 5-10 years for it to reach maximum production. An apple tree can live 15-100 years depending on the rootstock. Most nut trees are still considered young at 100 years, and oaks can still be called young at 200 years of age!

When we select our trees based on current temperature data, we are not considering Succession. We are not considering what the climate will be like in 10 or 20 years, let alone 100 or 200 years from now. But this is what we need to consider if we want to be visionary designers.

So let’s get down to it. What do we actually do with this knowledge?

First, we assume that the climate will change, and monitor the climate yourself. This doesn’t have to take a lot of time. Just be aware of global, regional, and local climate trends. Monitor the conditions on your own land, and maybe consider keeping some records. Be aware.

Second, we assume that scientists will be wrong. We can’t invest all our energy and the huge investment of time that a tree’s life represents on what the current weather geeks are telling us. We need to be wise. We heed their advice, but we hedge our bets. As a physician, I have seen the pendulum swing back and forth in the science of medicine… Eggs are good. Eggs are bad. Fat is bad. Margarine is good. Margarine is bad. Fat is good. Good fat is good. Avoid the bad fats. Eat fish oil. Avoid fish because of mercury. Avoid alcohol. Drink in moderation … and on and on it goes. Think about it. For the most part, people listen to “current” medical advice, often to their own peril. I don’t just say this because I am a physician, but most people trust that doctors have their best interest in mind. Now let’s consider the weatherman or woman. Hardly a trustworthy lot! They try to give us the 24-hour forecast, and they barely get it right half the time. I know, I know, the weatherpeople are not climate scientists. But who do you think creates the forecast systems those beautiful talking heads in front of the weather map on television use to give us the forecast? It is the climate and weather scientists. If they can’t give us a reliable forecast for a week, why should we trust them to tell us the weather a year from now, or a decade, or a century from now? As I said, we need to heed their advice, but we also need to hedge our bets.

Third, we choose our short-lived shrub and tree varieties based on the most current temperature data we have. Climate does not change very fast, so we want to have good yields of fruit and nuts as soon as possible. As the years pass, these short-lived plants will age and die. The average temperatures will likely have shifted during this time, and we can select replacements plants that are better suited to the new climate.

Fourth, the majority of our longer-lived trees should have a wide tolerance of temperature and moisture variations. We need to assume the weather is going to change. Likely it is going to continue to get warmer, but it could get cooler. Also, if things don’t change, there will be more and more droughts. We need to choose plants that are hardy in a variety of situations.

Fifth, we should include a percentage of our trees that are more heat tolerant. I am not saying that you should plant banana trees if you live in Minnesota, but start planting a few trees that do better in warmer climates yet will still live in your current coldest temperatures. We need to accept that these trees may not be very productive for quite some time, but if the weather continues to warm, they may become the most productive trees you have. Consider these trees an emergency fund, one you hope you never have to cash in, but you have it if you need it.

Sixth, if we have the space for it, we should include a smaller percentage of trees that are more cold tolerant. These are trees that can grow in warm temperatures, but may never fruit unless they have long, cold Winters. These are here just in case the majority of climate scientists have it wrong and the Earth is going to cycle down to cooler temperatures. The 1970’s had many people thinking that another Ice Age was on its way. Maybe the current scientists have it wrong. Consider these trees your lottery ticket. You don’t expect it to win, but if you have the extra couple of bucks… why not?

Seventh, every time you are ready to place a new plant, consider what the future holds for this plant during its entire life. We have to consider the end while at only the beginning if we are truly going to take responsibility for our own existence and that of our children.



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