“The garden suggests there might be a place where we can meet nature halfway.” Michael Pollan
Try as we might, there is no escaping the present discussions on climate change. According to a recent Fine Gardening Magazine article authored by Dr. Bert Cregg, an associate professor in Michigan State University’s horticulture department, it is well documented that since the Industrial Revolution, “atmospheric carbon dioxide levels have increased from around 280 parts per million to over 400 ppm,” a shift that has the potential to impact plants and gardening.
Cregg believes there are two long-term effects this change will cause.
One is that most plants will increase their photosynthetic rate (photosynthesis is the taking up of carbon dioxide by the leaves to produce sugars for plant growth, defense and storage), resulting in a “carbon dioxide fertilization” effect. This will result in weedy and invasive plants that are better able to take advantage of this and spread more quickly.
The other result is since carbon dioxide traps heat near the earth’s surface, it will cause rising temperatures, which, in turn, will cause higher winter temperatures as well as erratic extremes in weather.
Warmer winters would seem to be a good thing, until it’s realized that they can cause the northern spread of many insect pests, such as the hemlock’s woolly adelgid.
Another issue is that a warmer climate results in longer growing seasons for trees and shrubs. There is a downside to this, in that many are more liable to be damaged by spring frosts. For example, frost ruined many types of cherry and peach tree crops in March 2012.
As predicted by global models, Cregg said, there have already been extremes in weather, including more intense droughts and more extreme rain events. Recent and sudden bad flooding in Milesburg and surrounding areas could be an example of this.
Another interesting consequence of warming temperatures is a shift in the U.S. Department of Agriculture’s Plant Hardiness Zones (the standards that determine which plants can thrive in a certain location), meaning that some plants that were hardy in more southern states could be planted farther north. However, because plants respond to extremes rather than averages, plants from those warmer states thrived in mild winters, only to succumb to colder ones.
All of this, sadly, results in disruptions to relationships between pollinators, breeding birds, insects and the plants on which they depend.
Gardeners are a stalwart group and take seriously their role as stewards and guardians of the environment, so it seems a sure bet that they will be proactive in meeting this challenge.
Here are some proven ideas to help mitigate climate change effects; in other words, to meet nature’s unpredictability halfway.
Gardens can be adapted by having plant diversity to help counteract new insect pests that may arrive. Experimental plants can be mixed in, especially annuals and herbaceous perennials, with a foundation of those that are known to thrive. A good idea is not to invest more than can be lost.
I try to know my garden and its stress tolerance traits. I’ve learned that my succulents in containers, for example, cannot tolerate a series of heavy rains without roots rotting. I move them into the garage, when necessary, to minimize damage. Some plants are not flood tolerant; some, on the other hand, are not drought tolerant.
Mulching with a 2-to 3-inch layer of wood chips also is good advice because it helps the soil retain moisture and reduce soil temperatures when it is dry and hot, keeps weeds in check and insulates in the winter to help prevent frost heaving.
The National Wildlife Federation also recommends other actions to help reduce carbon footprints and slow future warming:
■ Use energy-efficient products like those that are LED or solar-powered and avoid using gas-powered yard tools, where possible, to reduce emissions. Substitute with tools that are human-powered, like push mowers (or even electric), hand clippers, rakes and brooms.
■ Burning just 1 gallon of gasoline releases 20 pounds of carbon dioxide into the atmosphere, so having less lawn is also helpful (less mowing, too).
■ Reduce water consumption in the garden by using a rain barrel and drip irrigation and adjusting the watering schedule to water in the cooler times of the day.
■ Compost garden and kitchen waste, which can significantly reduce methane, a highly potent greenhouse gas, and the finished product will be organic material to add to the soil.
■ Plant lots of longer-lived trees such as oaks or beeches that remove carbon dioxide from the soil and store it in their wood tissue, reducing it in the atmosphere.
“If every one of America’s 85 million gardening households planted just one young shade tree in their backyard or community, those trees would absorb more than 2 million tons of carbon dioxide each year,” according to the National Wildlife Federation.
■ Turn the backyard or community garden into a natural wildlife habitat, which can connect habitats or help maintain them.
No one can turn back time, but there are many small steps that can be taken now in gardens everywhere that can begin to provide a better, healthier future.
