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Trees of the Season

December 2014: Trees of the Season

December in the Northeast and Midwest can be stark. Autumn’s red, gold, and orange hues are long gone, replaced by shades of black, white and gray. It is at this time of year that we are particularly thankful for the muted green relief of firs, pines and spruce trees throughout the landscape.  We may not be the only civilization to appreciate the seasonal color: ancient peoples decorated their doors and windows with evergreen boughs in winter as a reminder that the sun and green plants would return. In the 1500s, the tradition of bringing a live Christmas tree into the home began in Germany. This month we feature a scientist, research, a product, and a partnership all relating to the trees of the season. 

Environmental Education Link


Every year, the Capitol Christmas Tree team develops lesson plans for K-12 students and educators to use as the National tree makes its way to Washington DC.

See the links below to create your own Capitol Christmas Tree ornament and to learn why a conifer’s tree’s adaptations to winter make it a particularly good Christmas tree.

Learn more about the Capitol Christmas Tree project.

Featured Scientist

Laura Kenefic

Laura KeneficResearch Forester Laura Kenefic’s roots in forest science go back to an 1800s farmhouse in rural upstate New York where she grew up surrounded by second-growth northern hardwood forest. Playing in the woods and streams around home, and in high school a love of science fairs, inspired an interest in environmental science that led her to study forestry as an undergraduate at Bingham University and to continue studying forest resource management at the SUNY College of Environmental Science and Forestry. She subsequently earned a PhD in forest resources from the University of Maine.

While attending the University of Maine, Kenefic worked part-time for the U.S. Forest Service, which also provided operational support for her work on studies associated with the Penobscot Experimental Forest (PEF), the site of a then-45-year-old silvicultural study in northern conifers.  The work at the PEF is a great fit for Kenefic because, as a silviculturist, she is interested in compositionally and structurally diverse forest stands, and in sustainable management of those ecosystems.  The long-term studies on the PEF include more than a dozen different silvicultural treatments and exploitative harvesting practices, providing a rare opportunity to quantify outcomes of management and compare different alternatives.

“The most enjoyable part of my work is sharing the results of those studies with researchers, forestry practitioners, educators, and students” Kenefic said.  “Helping people understand the consequences of the decisions they make about forest use, and allowing them to see the positive and negative outcomes in the field, is critical to improving the practice of forestry.  “Silviculture Matters” is the theme of our experimental forest tours, and the theme of my research program.  I am proud that my body of work supports that message.”

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Featured Product

Christmas Tree Pest Manual – 3rd Edition

Christmas Tree Pest manual overlayed on photo of Christmas tree farm with frost and winter injury. Background photo by Steven Katovich, USDA Forest Service, Bugwood.orgWe are not the only species that appreciates a good Christmas tree. From Douglas-fir needle midges and redheaded pine sawflies to deer and gophers, the third edition of the U.S. Forest Service’s Christmas Tree Pest Manual describes damaging pests that attack Christmas trees in North Central and Northeastern states.  The updated edition is the product of a collaboration among scientists at Northeastern Area State and Private Forestry, the Northern Research Station, Michigan State University and Purdue University. The popular manual was first published in 1983 and the second edition was released in 1998.   

You do not need to be a forester to appreciate the 164 page illustrated manual, available on line.   Succinctly written and loaded with photographs, it is designed to be an easy reference for growers as they inspect the trees in their nurseries and plantations.  Pests, symptoms and signs of tree injury, and management practices to maintain tree health are all described in detail and clearly illustrated in the manual. Much of the information provided will be helpful for diagnosing injury of conifer species in landscape plantings in addition to trees planted for Christmas trees.  

According to the National Christmas Tree Association, there are approximately 25-30 million real Christmas trees sold in the United States each year.  These trees are grown on 15,000 farms across the United States encompassing about 350,000 acres.  More than 100,000 people are employed full or part-time in the industry.  Suffice it to say that growing Christmas trees is a pretty big business. 

The information provided in the Christmas Tree Pest Manual is a powerful tool growers can use to keep trees healthy and beautiful over the 4-15 years it takes to grow a Christmas tree to a height of 6-7 feet.    

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Featured Research

Eastern Spruce Budworm

Research on spruce-fir forests impacted by spruce budworms helps scientists understand the complex dynamics of these forests. Photo by Doug Maguire, Oregon State University, Bugwood.org.In the continental United States, insects cause more economic damage to forests than any other type of disturbance.  In the northern spruce-fir forests of the Eastern U.S., the Eastern spruce budworm is a major player when it comes to damaging impacts.  Each fall, the insects prepare for a long winter’s nap in cocoons among the trees’ needles.  In spring, the larvae emerge and proceed to eat their way through the buds and needles of their host trees (fir and spruce).    

The spruce budworm naturally cycles between endemic (benign) and epidemic (damaging) states due to delayed responses to budworm populations by the insect’s natural enemies.  Epidemic budworm populations can kill fir and spruce across entire regions.  However, balsam fir appears well-adapted to budworm disturbance because dense seedlings are released by the decline of the canopy.  Research Ecologist Brian Sturtevant is studying how the Eastern spruce budworm affects the health and function of Eastern forests in a larger context that includes other disturbances, such as fire. 

In a recent study using remote sensing and simulation modeling tools, Sturtevant found that fire suppression in northern forests can favor dominance by spruce and fir, which may worsen budworm damage during outbreaks.  While the tree damage caused by the budworm temporarily increases fire severity in spruce/fir forests due to creation of dead fuel, over longer time scales fire risk is reduced due to the removal of live fir and spruce that act as ladder fuels to transfer the fire from the ground into the canopy. Understanding these complex dynamics helps forest managers achieve desired management objectives. 

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Featured Partnership

65 years of research on the Cutfoot Experimental Forest

With help from amateurs, a diverse group of experts revised a fungal family

Red pine, the state tree of Minnesota, is an important component of northern forests with diverse uses that include lumber, pulpwood, wildlife habitat, windbreaks and Christmas trees. Much of what we know about the ecology, productivity, and management of red pine has been learned through long-term silviculture experiments conducted on the Cutfoot Experimental Forest in northeastern Minnesota. These experiments could not have taken place without a remarkable 65-year partnership between the scientists at the Northern Research Station and staff of the Chippewa National Forest. 

One of the great challenges of maintaining such a long-term partnership is the change in staff over the years. Red pine studies on the Cutfoot Experimental Forest, and elsewhere on the Chippewa National Forest, have spanned the careers of three generations of scientists and national forest staff. “The partnership success is built on mutual respect and trust and a recognition that our respective organizations cannot do their jobs without each other,” said Research Ecologist Brian Palik “We rely on the Chippewa to partner with us to design and implement our experimental treatments. In turn, we provide the Forest with information on how to maintain the health and productivity of red pine forests.” 

The partnership is an example of scientists and managers working hand-in-hand to achieve mutually beneficial outcomes. 

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