Purdue University - Extension - Forestry and Natural Resources
Got Nature? Blog
The focus of forest science is increasingly shifting to the management of forests as complex systems rather than as simple agricultural landscapes—with a much greater appreciation for the interactive ecosystem processes. In addition, now for many forest landowners, the ecological value of their land is at least as important as the economic return. It is, therefore, vital to understand how forest management affects not only timber production, but also the overall function of forested ecosystems.
This new publication, Breeding Birds and Forest Management: the Hardwood Ecosystem Experiment and the Central Hardwoods Region, summarizes the effects of forest management on bird species in the Midwest based on data collected as part of the Hardwood Ecosystem Experiment (HEE) in southern Indiana and other studies. We hope this summary provides a basis for understanding interactions between forest management and forest birds as well as guidelines for bird-friendly forest management in Indiana.
Resources
Hardwood Ecosystem Experiment
Hardwood Tree Improvement and Regeneration Center (HTIRC)
The Education Store, Purdue Extension Resource Center
Article shared in NASF May 15, 2015, E-Newsletter
Lloyd Alter, Managing Editor
TreeHugger.com
As we continue to burn through our nonrenewable resources at an alarming rate, it is important that we never underestimate what we can do with our resources that can be replenished. One of these, wood, is an extremely valuable material but has been underutilized in construction for one big reason: fires. Every so often, a wood structure like the 188-unit apartment complex in Richmond, BC, burned down in 2010 goes up in a blaze and hinders the support of timber construction in a big way. While this is a valid concern, there are several things to consider before abandoning hope. Most of the big building fires covered by the news have been on uncompleted buildings still under construction. This means that fire suppression systems haven’t been installed yet, and oftentimes incomplete floors lacking fire-retardant drywall, or walls of any kind, give the fire huge ventilated areas to spread. This is hardly fair to mark these fires as a failure of wooden construction. In completed buildings, close to 80 percent of fires are contained to the rooms they are started in.
Furthermore, fire damage isn’t limited to wooden buildings. Structures made of concrete, steel or other construction materials can still weaken and collapse under the heat of a fire. In fact, heavy timber resists fire very well, burning slowly and creating a layer of char that helps to preserve the structural integrity of the inside wood.A recent advancement in timber technology to note is Cross-Laminate Timber, or CLT. CLT is made from stacks of industrially dried and fully glue-coated lumber. It is exceptionally strong, multi-purpose and lightweight. Construction using CLT is quick because it is easy to prefabricate and transport. Like heavy timber, CLT produces a layer of char when burned, and when used in construction, engineers factor in this layer and use enough wood to allow charring to form while still maintaining enough internal wood to be structurally sound. Also cosmetically, CLT looks pleasing and can be left exposed, reducing building cost. CLT has been considered the future of wood-based construction and for good reason.
So with some of the negative stigma of wooden construction debunked and the values of timber buildings explained, this leaves the biggest value of it all to think about: renewability. Timber is the only 100% renewable material for building construction. One billion cubic meters of logs are produced each year in North America and Europe alone, creating 200 million cubic meters of engineered timber and done in a careful way so that forests maintain their size. This is enough material to build 150,000 offices a year. Timber also locks up carbon that was absorbed by the tree during its growth, reducing pollution. As we look to the future, we should look to the trees. It’s time for timber construction.
Resources
NASF May 15, 2015 E-Newsletter, National Association of State Foresters
Making the Case for Wood Construction, Treehugger
Timber Offices: The Time Has Come, ARUP
The Education Store, Purdue Extension Resource Center (search “timber”)
What is Cross Laminated Timber? American Wood Council
2014 Indiana Forest Products Price Report and Trend Analysis, Indiana Department of Natural Resources
National Association of State Foresters
Question: I just finished cutting down the last of my backyard oaks due to oak wilt. I have also lost several redbuds due to verticillium wilt. I would like to replant a tree in the spot where the oaks and redbuds were, but I would like some advice on the most resistant tree I can find. I live in Crown Point, IN, primarily clay, on a slope, with heavy brush on my property lines. I know most people would say NEVER plant again once wilt has been detected, but I thought I might ask before giving up (and moving all my shade plants). Do you have information/research on an appropriate and sturdy replacement shade tree?
Response: In general, replanting of oaks in an old oak wilt disease center does not result in disease occurrence in the replanted trees. Root grafts are not thought to form with the dead, diseased oaks. It does not appear that the fungus is transmitted outside the primary phases of transmission: vector-borne via insects (e.g., Nitidulidae) and xylem-limited disease spread via live root grafts of infected trees (MacDonald et al., 2009). This does not mean, of course, that the young oak trees as they grow and age over time are immune to oak wilt; rather, it simply means that oak wilt is not sitting dormant in the soil waiting to attack newly planted or germinated oak seedlings.
Thus, it is only through insect spread from active oak wilt centers in the vicinity that disease would occur in replanted oaks. Healthy oak trees are not susceptible to oak wilt in an infected area. Bur oak, white oak and other members of the white oak family are resistant to the fungus and can be planted in oak wilt centers. For additional prevention measures, plant tree species other than Oaks to guarantee no infection from the disease.
Resources
Diseases in Hardwood Tree Plantings, The Education Store
Tree Installation: Process and Practices, The Education Store
Forest Health Problems Impacting Indiana Forest Resources, Indiana Department of Natural Resources
Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources
Question: Weeping willow, six years old and 9″ diameter. Wet, clay ground and thriving. Suddenly late last summer, I noticed the leaves were dead, and the bark on the trunk was completely loose and falling off. No other trees or shrubs within 50 feet (black walnut, sycamore, maple, rose of sharon) were affected. No obvious sign of insects, boring, trails, worms, etc.
Answer: When a tree starts to lose leaves, especially in the spring when they should be expanding for the new growing season, it can be puzzling. Often, this is a sign of troubles which can be caused by biotic or abiotic issues but not always a major cause for alarm. The dropping leaves can be a symptom of foliar diseases which weakens the tree, or it could be the result of an insect pest feeding on the petioles of the leaves. There are many pests which can cause leaf drop.
Another possible cause is the response to abiotic disorders which is typically a complex of issues. Leaf drop can occur on trees that have been exposed to prolonged wetness in heavy, clay soils. Some tree species like wet soils but not prolonged wetness without drainage. If trees are exposed to continual wetness, their roots can become diseased and cause the leaf drop. Additionally, it has been noted that trees which were planted improperly, especially if planted too deep, can result in several physiological issues such as decline and dieback.
If trees reveal symptoms of premature fall color, yellowing of leaves or unusual leaf drop, it may be necessary to send in a sample for diagnosis. The Purdue Plant and Pest Diagnostic Laboratory (PPDL) provides this service by a very capable team of pathologists, entomologists and extension specialists to analyze plant issues in the landscape. This is an inexpensive approach to investigating the issues and leading to the best possible curative measures. Protocol for submitting plant samples can be found on the PPDL website.
Resources
Hardwood Tree Improvement and Regeneration Center, Paula Pijut, Research Plant Physiologist, Purdue University
Relationships Between Advance Oak Regeneration and Biotic and Abiotic Factors, Songlin Fei, Associate Professor of Measurements and Quantitative Analysis, Purdue University
Diseases of Landscape Plants: Leaf Diseases, The Education Store, Purdue Extension Resource Center
Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources, Purdue University
If you’re walking in the woods or maybe even traveling along a road this spring in Indiana, you may come across some trees that look like the one in the photos. Clearly, something unusual is going on here. What made the bark change color so quickly, and why are there holes in the bark?
The answer to both of those questions for ash trees around the state is Emerald Ash Borer and woodpeckers. As Emerald Ash Borer spreads across Indiana, the population of Emerald Ash Borer larvae overwintering under the bark of ash trees can quickly increase. These grubs provide a tasty treat and important winter and early spring nutrition to hungry woodpeckers.
Woodpeckers of several species are experts at detecting and extracting these grubs by pounding holes in tree bark. Ash bark is generally gray on the surface, but the inner bark is a light corky tan color. Once the woodpeckers find the EAB larvae, their excavation activities flake off the outer bark to expose the lighter colored inner bark. This is actually one of the best indicators of the presence of Emerald Ash Borer in a tree. The woodpecker activity often starts in the upper main stem and branches of ash trees, but as the population of EAB larvae in the trees increase, the woodpecker activity spreads down the trunk of the tree. Trees with this much inner bark exposed indicate an advanced infestation of EAB and signal ash tree mortality in the next year or two.
If you would like to learn more about ash trees and the Emerald Ash Borer, visit the Purdue Emerald Ash Borer website.
Resources
Arrest That Pest! – Emerald Ash Borer in Indiana, Purdue Extension
Purdue Extension – Forestry & Natural Resources website with search bar, place “Invasive Insect”
Emerald Ash Borer, Indiana Department of Natural Resources (IDNR)
Emerald Ash Borer in Indiana, Purdue Extension
New Hope for Fighting Ash Borer, Purdue Extension – Forestry and Natural Resources Got Nature? blog
Lenny Farlee, Extension Forester
Purdue University Department of Forestry and Natural Resources
When you rush to the closet to grab your favorite shorts and T-shirt, remember that you are not the only creature looking forward to the warmer weather. It is important to check yourself or have a buddy check you for passengers when you get back from the field to lessen the likelihood of bringing ticks home with you.
Indiana has 15 tick species, but the three listed below are the most prevalent.
American Dog Tick (Dermacentor variabilis): Found primarily along trails, walkways or in fields, American Dog ticks are rarely found in forests. Despite their name, these ticks feed on a multitude of hosts in addition to the family pet and can transmit Rocky Mountain Spotted Fever, a potentially fatal disease contracted by 32 people in Indiana last year. The American Dog Tick also carries Tularemia, a rare but dangerous disease that is often misdiagnosed for the flu.
American Dog ticks can survive for two years at any stage in life until a suitable host is found. Male ticks mate with the female while she is feeding as after she is sated, she drops off of the host and lays 4,000+ eggs before dying. Larval ticks only feed for three to four days from a host before molting into nymphs. The nymph feeds on a variety of small/medium-sized hosts before dropping to the leaf litter and molting into adults. Interestingly, these ticks are least likely to bite humans.
Lone Star Tick (Amblyomma americanum): Found primarily in dense underbrush and forested areas. As with the American Dog Tick, these ticks are capable of transmitting Rocky Mountain Spotted Fever in addition to Monocytic Ehrlichiosis, another tickborne disease that presents with symptoms similar to the flu but was confirmed in 49 Indiana cases in 2013. ‘Stari’ (Southern Tick-Associated Rash Illness) Borreliosis is a tick-vectored disease that presents with a large round or elliptical rash and flu symptoms transmitted by the Lone Star Tick.
Voracious eaters, adult Lone Star ticks often take human hosts or other large mammals. After a week, the female is capable of laying 3,000+ eggs. The larval Lone Star ticks only feed for four days before detaching, burying themselves in leaf litter and molting into nymphs. Able to quickly ascend up pant legs, these nymphs can be firmly attached to a host in < 10 minutes. After five days, the nymphs detach and molt into adults.
Black-legged or Deer Tick (Ixodes scapularis): Found primarily in deciduous forests, these ticks predominantly use white-tailed deer or other large mammals as hosts. Unlike the relatively accelerated life cycles of the American Dog and Lone Star ticks, the Deer Tick life cycle takes nearly two years to complete.
Deer ticks are most notorious for spreading Lyme disease, a dangerous disease that causes flu-like symptoms that, if left untreated, can spread to joints and compromise the nervous system. More than 100 cases of Lyme disease were confirmed in Indiana in 2013. Babesiosis is caused by microscopic parasites that infect red blood cells, and Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum. Both of these diseases are transmitted through the bite of an infected Deer Tick.
Only the female Deer Tick feeds, and once completely engorged, they lay an egg mass of 1,900+ eggs before dying in late-May. Deer Tick larvae and nymphs remain in the moist leaf litter within forested areas and prefer smaller hosts. After feeding for three days in each developmental stage, they burrow into the litter to molt. Larvae emerge as nymphs in spring, and nymphs emerge as adults in fall.
The table here illustrates the months of activity for the larval, nymph, male and female tick life cycle stages which gives you a quick reference for Indiana. This information was gathered from the resources listed in this post.
Indiana ticks can carry several diseases, but the three most common are Rocky Mountain Spotted Fever, Lyme Disease and Ehrlichiosis. Symptoms of all three diseases range from spreading rashes, headaches, fatigue, fevers and muscle aches. Likelihood of infection is rare; however, instances of each disease are increasing in Indiana.
Be careful and try not to pick up eight-legged hitchhikers. If you suspect that you have been bitten by a tick or develop a rash along with flu symptoms, contact your local health department for a disease screening.
Resources
Ticks, Indiana Department of Natural Resources
Ticks, Medical Entomology, Purdue University
Rocky Mountain Spotted Fever, Centers for Disease Control and Prevention
Tularemia, Centers for Disease Control and Prevention
Lyme Disease, Centers for Disease Control and Prevention
Ehrlichiosis, Centers for Disease Control and Prevention
Parasites – Babesiosis, Centers for Disease Control and Prevention
Anaplasmosis, Centers for Disease Control and Prevention
‘Stari’ Borreliosis, Columbia University Medical Center
tickencounter.org, Tick Encounter Resource Center, University of Rhode Island
Shaneka Lawson, Adjunct Assistant Professor
Department of Forestry and Natural Resources
A 20+ extension team led by Kara Salazar, sustainable communities extension specialist, and Michael Wilcox, assistant program leader for extension community development, have produced a new publication and curriculum titled “Enhancing the Value of Public Spaces.” This must-have spiral bound notebook and curriculum zip file download is a great resource for decision makers and local leaders developing community public spaces including park boards, planning commission members, members of organizations, public officials and staff whose missions are related to providing services, programs or management of public spaces. This program serves as a “how-to” guide for creating high-quality action plans to achieve great public spaces.
A one day workshop starts the process with collaborative activities to identify best practices for improving public spaces with emphasis on forming partnerships to achieve desired community goals. Follow-on working group meetings provide the resources and technical support needed to plan and implement projects tailored to individual communities. The completed high quality public spaces action plan can be used as part of comprehensive planning efforts, parks and recreation master plans and fundraising initiatives.
Resources
Enhancing the Value of Public Spaces, The Education Store
Kara Salazar, Sustainable Communities Extension Specialist
Department of Forestry and Natural Resources
Illinois-Indiana Sea Grant
Michael Wilcox
Assistant Program Leader, Extension Community Development Program
Senior Associate, Purdue Center for Regional Development
In the first study of its kind, scientists David Nowak and Eric Greenfield of the U.S. Forest Service Northern Research Station have calculated just how beneficial trees are to human health. As well as providing oxygen, shade and beautification, trees help to remove air pollution by catching harmful airborne particles on the leaves and branches and by absorbing gases like nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2). Nowak and Greenfield concluded that trees save over 850 human lives a year and prevent over 670,000 cases of acute respiratory symptoms from diseases like asthma, bronchitis, emphysema and chronic pulmonary obstructive disease (COPD).
While trees in suburban areas remove a higher amount of pollution due to their large quantity, urban trees have a greater direct effect on human health and monetary savings due to their closer proximity to people. Altogether, trees improved air quality in the continental U.S. by less than 1% in 2010, according to computer simulations iTree and BenMAP. This might not sound like much, but this means that trees removed 17.4 million tons of air pollution and saved the country over $6.8 billion in medical expenses. This really goes to show how much of a difference trees can add to the quality of our lives, especially in urban areas.
Resources
Tree and Forest Effects on Air Quality and Human Health in the United States, Science Direct
Urban Trees Help Us Breathe, National Association of State Foresters
Value of Urban Forests, U.S. Department of Agriculture (USDA)
iTree, U.S. Forest Service
BenMAP, United States Environmental Protection Agency
U.S. Forest Service Northern Research Station
If a bad haircut was fatal, you would be very choosy about your hairstyle. But each year, hundreds of homeowners have their trees pruned by topping, a horticultural “bad haircut” that shortens the life of the tree and leads to greater expense later.Tree care professionals and university experts caution tree owners that topping a tree is the kiss of death in many instances. This damaging pruning practice can shorten the life span of trees significantly, and the damage is long-term; in some instances, the beheaded tree will die within a few years, if not less.
Many people don’t realize topping is a poor practice because trees can be remarkably effective in overcoming the damage in the short term – some can take years to die, a few can even withstand multiple toppings. So the real damage is not easily noticed by the tree owners until the trees can no longer survive such a drastic removal of canopy.
People see trees leaf out year after year and give little thought to the actual effect of the topping. The most immediate effect is a reduced leaf mass, or crown. This smaller number of leaves reduces the amount of energy the tree manufactures to sustain itself. Less energy causes the roots to die back as well. This creates a tree that is less able to supports itself or withstand heavy winds.
The haircut analogy breaks down when you look at what happens after the tree topping occurs. Whereas hair just continues to grow out from the same follicle, branches do not continue to grow out from the same growing point. Tree limbs sprout from previously dormant buds just below the internodal pruning cut. This causes an unhealthy flush of growth near the end of the poorly pruned branch that is typically thin and weakly attached to the tree’s main growth stems.
These weak limbs are easily ripped from the tree in storms, causing damage and creating a liability for property owners. It has been long known that tree topping is harmful to trees, yet the practice of tree topping continues. Reputable arborists will work with a tree’s natural growth habit when pruning and understand the importance of pruning and tree health. Proper pruning can extend the life of a tree and reduce ongoing homeowner expense; however, once a tree is topped, it will require much more frequent pruning to prevent branch failure, costing the owner more money.
The best advice is to hire reputable tree care companies that have recognized qualifications and insurance. Ask the company for credentials from professional organizations such as the International Society of Arboriculture and the Tree Care Industry Association to prove their knowledge and abilities. Also ask for references of where they have pruned trees at other properties to see what their work looks like after the project. A homeowner wouldn’t hire a plumber or carpenter without references, so why shouldn’t an important asset to your property like trees not receive the same consideration?
Trees are a valuable resource and asset to your property that helps make our environment cleaner, healthier and a more beautiful place to live. Those trees deserve better than a life-shortening bad haircut.
Resources
What’s Wrong with Topping Trees? The Education Store
Trees and Storms, The Education Store
First Aid for Trees, Indiana Department of Forestry and Natural Resources
Prune Your Trees, Indiana Department of Forestry and Natural Resources
Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources, Purdue University
For many different reasons, more and more people in larger cities want to reuse urban trees scheduled for removal. People who are part of the “green movement” want to turn urban trees into something more valuable than firewood, mulch or just trash for the local landfill. This publication describes the pros and cons of using urban trees for lumber, the types of lumber that are economical to produce from urban trees and how you might find a sawyer who can turn your tree into usable lumber.
Resources
Mechanical Damage to Trees: Mowing and Maintenance Equipment, The Education Store
The Education Store, Purdue Extension Resource Center (Find apps, publications, videos and much more)
Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources, Purdue University
Daniel Cassens, Professor of Wood Products
Department of Forestry and Natural Resources, Purdue University
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