Davey Tree Flipbooks

20 THE DAVEY BULLETIN | July/August 2018 Q-AND-A ON CLIMATE CHANGE The Bulletin: What causes the climate to change? Herms: Whenever the Earth's temperature changes it is in response to some force that alters the thermodynamic equilibrium of the planet. Something is making the temperature change. It could be changes in the Earth's orbit, or it could be caused by an accumulation of greenhouse gases (CO2) in the atmosphere, which almost all scientists agree is what is causing temperature increases we're seeing today. There are no naturally occurring phenomena that could be causing the changes we are witnessing. The Bulletin: How does climate change affect our clients? Herms: Warmer temperatures are contributing to more pest problems in some areas. In recent years temperatures during winter months have not been falling low enough, for long enough periods of time, to reduce insect populations. For example, pests like the southern pine beetle now are being found as far north as New Jersey, where trees are being attacked and killed by a pest they have not encountered before. The same situation is happening in the Western U.S. with the mountain beetle. These pests are expanding their reach, attacking more and more trees each year as rising temperatures foster growth in the insect population. A client who lives on the southern edge of a plant's distribution zone will likely find that plant or tree becomes more stressed due to higher temperatures. That stress makes the plant more susceptible to disease and pests, and that means it will need greater care to maintain its health. The intensity of storms, including hurricanes, is increasing, posing greater threats to trees and plants in the Southeast and along the East Coast. Greater precipitation levels in spring months in some regions are contributing to higher levels of fungal diseases, whereas severe droughts are stressing plants in other areas. All of this adds up to a tougher environment for trees to grow and thrive in. ABOVE THE CANOPY Since the 1980s, the Earth has started warming faster than it has since the end of the last ice age almost 12,000 years ago. Our planet is changing. As leaders in the green industry, it's important all Davey employees have a sense of how that change can affect the way we think about, and care for, the natural environment. Climate change is a complex topic. It can be difficult to understand. So, The Bulletin sat down with Dan Herms, vice president of research and development, to answer some basic questions about climate change. The Bulletin: How is climate different from weather? Herms: I've heard a simple, helpful analogy that climate is like the collection of clothes in your closet. Whereas weather is the clothing that you wear on a daily basis. Climate is a long-term average of weather patterns. Weather, which varies daily, is difficult to predict more than a few days in advance. Climate, we know, is easier to predict both on a short-and-long-term basis. The Bulletin: What is climate change? Herms: Climate of course is always changing and always has. We've gone through periods of changes where much of North America as we know it today was buried under thousands of feet of ice. Sea levels fall and rise as ice ages come and go. The average temperature of the Earth increases or decreases over time for many reasons. And those temperature changes cause other changes in climate, such as in precipitation patterns. Some areas of the planet see more rain, some see less. We see forests become deserts and other dramatic changes over long periods of time. Specifically, since the beginning of the 20th century, the planet has been warming. In a little over 100 years, the average temperature of the planet has risen 2 degrees Fahrenheit. This may not seem like much, but the effects on our environment are already apparent. Particularly since the 1980s, the Earth has started warming faster than it has since the end of the last ice age almost 12,000 years ago. The Earth is now warmer than it has been at any other time since the end of the last ice age.

• Cover