Conifers

Every year, Americans buy somewhere between 35 million and 50 million Christmas trees, and many more pull an artificial tree out of storage for the season. In all, about three-quarters of U.S. households typically have some kind of Christmas tree, surveys show. People often ask which is more sustainable – a real tree or an artificial one? It’s a big debate, and the answer depends on who you ask and which factors you consider. A more useful question is: How do I find the most sustainable tree of the kind I want to get? I’m a forestry professor who works on issues of sustainability. There are advantages and disadvantages to both cut trees and artificial trees. Here are some tips to consider for each. Cut Christmas trees require water and maintenance – and careful thought about disposal. 10'000 Hours/DigitalVision via Getty Images If you’re buying a live Christmas tree W...

Strong winds blew across mountain slopes after a record-setting warm, dry summer. Small fires began to blow up into huge conflagrations. Towns in crisis scrambled to escape as fires bore down. This could describe any number of recent events, in places as disparate as Colorado, California, Canada and Hawaii. But this fire disaster happened over 110 years ago in the Northern Rocky Mountains of Idaho and Montana. The “Big Burn” of 1910 still holds the record for the largest fire season in the Northern Rockies. Hundreds of fires burned over 3 million acres – roughly the size of Connecticut – most in just two days. The fires destroyed towns, killed 86 people and galvanized public policies committed to putting out every fire. Many residents of Wallace, Idaho, fled on trains ahead of the 1910 blaze. Volunteers who stayed saved part of the town, but about a third of it burned. R.H. McKay/U.S. Forest Service...

Wildfires and severe drought are killing trees at an alarming rate across the West, and forests are struggling to recover as the planet warms. However, new research shows there are ways to improve forests’ chances of recovery – by altering how wildfires burn. In a new study, we teamed up with over 50 other fire ecologists to examine how forests have recovered – or haven’t – in over 10,000 locations after 334 wildfires. Together, these sites offer an unprecedented look at how forests respond to wildfires and global warming. Our results are sobering. We found that conifer tree seedlings, such as Douglas-fir and ponderosa pine, are increasingly stressed by high temperatures and dry conditions in sites recovering from wildfires. In some sites, our team didn’t find any seedlings at all. That’s worrying, because whether forests recover after a wildfire depends in large part on whether new seedlings can establish themselves and grow. However,...