Got Nature? Blog

Posted on October 17th, 2018 in Forestry, Urban Forestry, Woodlands | No Comments »

It all starts with providing some supplemental nutrition for small to medium-aged trees in the late fall when trees go into a state of dormancy. This is when trees stop active growth and begin to form terminal buds, drop leaves and develop cold resistance.  Adding fertilizer to trees too early in the season can push new growth which will be prone to winter damage.

A fertilization program is used to maintain trees in a vigorous condition and to improve their immune system against pests. Fertilizing trees refers to the practice of adding supplemental nutrients (chemical elements) required for normal growth and development. However, you really can’t “feed” a tree, since trees are autotrophs. They use nutrients to feed themselves by making sugar in the leaves through photosynthesis.

Figure-1

Applying fertilizer to newly established tree 3rd year after transplanting.

Nitrogen (N), phosphorus (P), and potassium (K) are plant nutrients needed in the largest quantity and these are most commonly applied as a complete fertilizer. However, the addition of any soil nutrient is recommended only if soil or plant foliage tests indicate a deficiency. For trees and shrubs in most of Indiana, the two most common causes of nutrient problems are high pH (alkaline) soils, which can lead to chronic deficiencies of nutrients in some tree species, such as red maple and pin oak, and nitrogen-deficient soils. Typical symptoms include yellowing chlorotic leaves and reduced growth and smaller leaf size.

Trees in natural settings get nutrients from the air, organic matter, nutrient cycling, and microbial activity. In many cases, supplemental nutrition is not necessary in fertile soils which have enough nutrients in the proper amounts to support healthy growth, especially on established trees, but in the urban and suburban environment, often a little assistance is needed. The more challenging urban environment provides less opportunity for healthy growth due to poor, fragmented soils, reduced microbial activity and compaction. Trees needing fertilization to stimulate growth include those exhibiting the symptoms of pale green, undersized leaves, chlorosis, reduced growth rates and those in decline resulting from insect attacks or disease problems. Also, turf can be a serious contender for nutrients and trees surround by turf benefit from additional nitrogen applications every couple of years.

Trees which should not be fertilized include newly planted trees in the current year and those with root damage from recent trenching, construction or other disturbance. The root systems of these plants will need to re-establish before fertilizers are applied with cultural practices such as supplemental moisture and mulch. Older, established trees do not need to be fertilized every year and may never need supplemental feeding. In fact, serious pest problems can result on over-fertilized trees. Research indicates that young deciduous trees benefit from additional nitrogen in low-analysis, slow release forms.  Conifers require less fertilization and are genetically adapted to low-nutrient soils.

For more information on how and when to fertilize trees, refer to HO-140-W, Fertilizing Woody Plants from the Purdue Extension Education Store.

Article shared by: The Landscape Report, Start Preparing Trees for Winter and Next Year.

Resources:
Trees and Storms, The Education Store, Purdue Extension’s resource center
Tree Risk Management, The Education Store
Fertilizing Woody Plants, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources


Trees with colored leaves.For many people, the autumn season welcomes a pleasurable change in the weather.  We notice, even during a warm fall day, the air gets cooler and the brisk breeze forces out the fleece.  There are a couple of questions to be asked every year at about this time. Why do leaves change color and drop their leaves when fall weather appears?  Much of it has to do with day-length and temperature. The important thing is not that the amount of sunlight has decreased but rather the amount of dark has increased. The plants we’re talking about in this case are the deciduous trees, which are the trees producing the vibrant colors and those that lose their leaves annually. These woody plants “sense” the days are getting shorter during late September as winter slowly creeps in on us. Things like pigment, light, weather conditions; plant species, soil type and location all play important roles in the fall party and colorful confetti trees create for us to enjoy.

When daylight hours are less and temperatures are cooler, photosynthesis slows down and there is less chlorophyll production. This reduction reveals yellow or orange pigment called carotenoids and are usually hidden by the abundance of chlorophyll present in leaves during the growing season.

Unlike chlorophyll and carotenoids, which are present in leaf cells throughout the growing season, anthocyanins are produced mainly in the fall. These natural chemicals give color to familiar fruits such as cranberries, red apples, cherries, and plums. These complex compounds in leaf cells react with excess stored plant sugars and exposure to sunlight creating vivid pink, red, and purple leaves. A mixture of red anthocyanin pigment and beta carotene often results in the bright orange color seen in some leaves.

The cool fall temperatures cause the closing of leaf veins and prevent sugars from moving out which prolongs fall color. Thus a succession of warm sunny days and cool crisp nights can create quite a display.

Soil moisture levels have an impact on the ability to produce good fall color. A prolonged drought can delay color change for a few weeks. The ideal conditions for producing the best colors are good summer weather, with timely rainfall, and sunny fall days with the cool night temperatures.

Tree species vary in their ability to provide fall color, as some trees just don’t produce anything noteworthy. Color depends on the nutrient levels of iron, magnesium, phosphorous, or sodium in the tree.  Some tree species displaying yellow foliage are ash, birch, beech, elm, hickory, poplar, and aspen. Red leaves are seen most often in dogwood, sweet gum, sumac, and tupelo trees. Some oaks and maples present orange leaves while others range in color from red to yellow, depending on the species.

Even with these facts the timing, location, and intensity of autumn color are not completely predictable. To truly experience the colorful display you must be tuned in to your trees and your weather.  Get outside and enjoy the party our woodlands are providing and enjoy nature’s beautiful confetti.

Resources:
It’s Fall, but why are the leaves still green? article and video, WLFI.com
It’s late October and many leaves on trees are still green. What’s up with that?, IndyStar.com
Why Leaves Change Color, The Education Store, Purdue Extension
Why Leaves Change Color, USDA Forest Service, Northeastern Area
Fifty Trees of the Midwest App for the iPhone, The Education Store
Native Trees of the Midwest, The Education Store
Trees and Storms, The Education Store
Tree Installation: Process and Practices, The Education Store

Lindsey Purcell, Urban Forestry Specialist
Purdue Forestry and Natural Resources


Posted on September 7th, 2018 in Forests and Street Trees, Urban Forestry | No Comments »

A recent study at the University of British Columbia noted that a single tree along an urban street can help alleviate winds, shade pedestrians, and decrease wind pressure on nearby buildings. For both homes and businesses, the presence of trees can help decrease costs associated with maintaining indoor temperatures.

flickr.com, photo credit: Kris Arnold

Photo credit: Kris Arnold, flickr.com

Researchers used remote sensing technology to create intricately detailed computer models of a neighborhood that included each tree, garden, and structure. The models were able to elucidate how various scenarios (no trees, bare trees, full-leaf trees) influence airflow, thermal patterns, and overall radiant heating and cooling throughout the streets of the neighborhood. Resultant data indicated trees at various stages can decrease wind speeds by as much as a factor of two. For example, a strong 30km/h wind could be reduced to a comfortable 15km/h breeze.  The results also showed trees reduced the strain caused by wind pressure on building spaced closely together and farther apart. Close examination of the data indicated wind pressure causes up to a third of the costs associated with energy consumption and increased costs up to 10% in winter and 15% in summer. Using data gleaned from over a decade of measurements (from a monitored wind tower), they discovered even leafless trees are beneficial in winter months to regulate air flow and wind pressure on buildings.

This modeling effort represents the first of its kind to simulate actual neighborhood conditions using an existing neighborhood recreated in great detail as a model. Further work of this kind can be used to predict storm effects on structures and pedestrian movement. These data can assist engineers and city planners in the creation and layout of buildings, streets, and greenery while limiting energy losses and help evaluate proposed effects of weather forecasts throughout the neighborhood.

flickr.com, photo credit Rob Young

Photo credit: Rob Young, flickr.com.

References:
M.G. Giometto, A. Christen, P.E. Egli, M.F. Schid, R.T. Tooke, N.C. Coops, M.B. Parlage. 2017. Effects of trees on mean wind, turbulence and momentum exchange within and above a real urban environment. Advances in Water Resources, 106: 154 DOI: 10.1016/j.advwatres.2017.06.018

University of British Columbia. Trees can make or break city weather. Science Daily, 26 July 2017.

Resources:
Tree Selection for the “Un-natural” Environment, The Education Store – Purdue Extension’s resource center
Planting Your Tree Part 1: Choosing Your Tree (Youtube video),  Purdue Extension-FNR
Tree Installation: Process and Practices , The Education Store
Tree Planting Part 2: Planting a Tree (Youtube video), Purdue Extension-FNR
Top 5 List for Tree Selection and Planting, Got Nature?, Purdue Extension-FNR
Indiana’s Urban Woodlots, The Education Store

Shaneka Lawson, USDA Forest Service/HTIRC Research Plant Physiologist/Adjunct Assistant Professor
Purdue University Department of Forestry and Natural Resources


Indiana batAt different times of the year, I get questions about bats in structures.  Bats are a timely issue towards the end of summer because young bats will soon be able to fly.  Excluding bats from structures is limited to this time.  This process is typically called “venting” where access points (both in use and potential) are identified, most are sealed off, and the remaining points are fitted with one-way doors that allow bats to leave but not reenter. If only the opening they use is sealed off, they will simply use another entry point. Think of it this way – our houses have multiple points of entry, but you may only use one. You will use another if necessary.

Bats can make their way into a house in a number of ways – gaps between siding and chimney, gaps between roof sheathing and fascia board, etc.  New and old construction alike. Eliminating access to all of these small, potential points of access can be a challenge. The bodies of some bat species are as small as your thumb. Even though you don’t have an attic, there are still spaces inside a structure where bats can live.

Bats are one of the most difficult wildlife conflicts to deal with because of the nature of their habits. They can pass through extremely small openings, move throughout the inside of a structure, and often entre/occupy hard to reach areas. Bat exclusion is not an activity I recommend for most homeowners.  There is a skill necessary to find and seal all possible access points. Since most of these are located high above ground and accessing these points can require special ladders, lifts and other safety equipment.

Having bats in the attic isn’t simply a nuisance issue, but also can be a safety issue. Like Most wildlife carry diseases. With bats, histoplasmosis and rabies are the two that are the ones most concern for people with bats in their homes.  The Center of Disease Control (CDC) has good information on these and other diseases. Fleas that live on bats can also be vectors for disease. It is always a good idea to limit exposure to wildlife animals as much as possible. For bats, venting in the end of summer and fall and preventing reentry is a logical first step.

If you have bats and want to solve the problem now is the time to contact professionals who can help. Unfortunately, most nuisance wildlife control operators don’t do bat work because it requires specialized equipment and the difficulty of it.  Because of that, control will not be cheap for the customer.  Many people construct bat houses to attract bats. While beneficial, artificial bat houses will not attract bats from an attic.

Resources:
Selecting a Nuisance Wildlife Control Professional, The Education Store-Purdue Extension’s resource center
Bats in Indiana, Indiana Department of Natural Resources (IDNR)
Bat Houses, Bat Conservation International

Brian J. MacGowan, Extension Wildlife Specialist
Department of Forestry & Natural Resources, Purdue University


If you’ve ever had to work on a tree leaf collection, no doubt you included a leaf from Indiana’s state tree. Also known as tulip poplar and yellow poplar, the tuliptree is actually not a poplar at all. It is a member of the magnolia family known botanically as Liriodendron tulipifera.

Indiana Tuliptree

A tuliptree, the state tree of Indiana.

The tuliptree is native to most of the eastern half of the United States and prefers rich, moist, well-drained, loamy soil. It is found throughout Indiana, but it is more prevalent in the southern two-thirds
of the state.

Its unusual flowers inspired the common name. The flowers are shaped much like a tulip with greenish-yellow petals blushed with orange on the inside. Because they generally are found high in the leaf canopy, the flowers often go unnoticed until they drop off after pollination. The leaves of this tree are also quite distinct — each one has a large, V-shaped notch at the tip.

Because tuliptrees transplant easily and grow fast, they are a popular choice for in home yards. But don’t be fooled by its small size in the nursery. Give a tuliptree plenty of room in your landscape plan. A tuliptree can reach as tall as 190 feet where it’s allowed to thrive, but it is more likely to reach 70 feet tall as a mature landscape specimen. Tuliptree is not without its share of pests and diseases. Among the most common are leaf spots, cankers, scale insects, and aphids….

For full article view “State tree a popular landscape choice,” Morning AgClips.

Related Resources:
Pruning Ornamental Trees and Shrubs, The Education Store-Purdue Extension resource center
Tulip Poplar: Is Indiana’s State Tree a Protector for the Rare American Ginseng Plant?, GotNature?, Purdue Extension – Forestry and Natural Resources

Rosie Lerner, Extension Consumer Horticulturist
Purdue University, Horticulture & Landscape Architecture


Trees offer many functional and aesthetic benefits, but one of the most common is shade. Because of this, one of the most important aspects of tree selection and planting is placement. Improper placement of trees can diminish the value of the tree on the site. The tree can actually become a liability if it conflicts with infrastructure or just does not providing any useful function at all. It’s important to consider and energy efficient design to obtain shade where it’s needed most such as south or west facing structures.Tree Shade

In this hemisphere, the sun is in the south and the source of cold weather is in the north. Whenever possible, place openings for sunlight and radiant heat primarily on the southern exposure, then on the west and east. For energy efficiency in winter, use the low arc of the sun to capture the maximum amount of warmth through east-, west-, and south-facing windows. Windows with a northern exposure are a source of cool air from prevailing winds during the hot months. So, give the north minimum exposure and maximum natural protection in the winter.

When selecting trees for energy efficiency, don’t plant evergreen trees near the house on southern exposures. Trees may provide some shade and screening but will also block out the warming effects of the sun during winter months. When choosing trees for shade and solar gain, choose larger, deciduous-canopy trees, which provide an advantage year-round. This means shade in the summer, blocking the sun’s energy. In the winter, after leaves have dropped, the sun’s energy can pass through the tree and into the window.

Tree Shade

Figure 1. Protection from the summer sun.

Select good quality trees from a reputable source that are suitable for your location. The old adage, “you get what you pay for” goes for nursery stock as well.  Correct placement is critical for an energy-efficient design and reduced maintenance as the tree grows and matures. Be certain the mature height and spread fit the location before purchase and planting the tree. This allows the tree freedom to spread into the design space naturally without excessive pruning needed to prevent conflicts with the home. However, the tree still must be close enough to the house for the canopy to provide shade. A good rule of thumb to begin placing the tree at least 20 feet from the house. For larger shade trees, you may need to plant as far as 40 feet from the house to insure room for growth (Figure 1).

Trees provide many benefits besides shade whichincludes cleaner air and increased property values. These ecosystem services are the reason why we plant trees, besides beautifying our landscape.

The functional benefits of shading help make homes energy-efficient by creating a cooling effect during the hot summer months and by allowing passive solar gain during cold winter months. However, proper selection and placement is critical to make the tree work for your site.  Choose wisely, plant properly.

Full article from Purdue Landscape Report.

Resources:
Tree Selection for the “Un-natural” Environment, The Education Store – Purdue Extension resource center
Planting Your Tree Part 1: Choosing Your Tree (Youtube video),  Purdue Extension-FNR
Tree Installation: Process and Practices , The Education Store
Tree Planting Part 2: Planting a Tree (Youtube video), Purdue Extension-FNR
Top 5 List for Tree Selection and Planting, Got Nature?, Purdue Extension-FNR

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


2017 Annual ReportPurdue Extension has posted its 2017 Annual Report online, highlighting the ways in which Extension educates empowers people throughout Indiana and promotes statewide economic vitality. The annual report includes stories regarding agricultural research in unmanned aerial vehicle use, key partnerships that return disabled farmers to their fields, enhanced economic futures in Indiana’s small towns, programs to increase health and wellness statewide, and much more.

Look to the future with Enhancing Public Spaces as this program grows and adds a health and wellness component. The Purdue University Extension program addresses public spaces and their role in enhancing the quality of place by helping regions, communities, and neighborhoods plan and prepare for a sustainable future.

Resources:
Purdue Extension Annual Report – 2016
What is Purdue Extension? – Purdue Extension Video

Purdue Extension

 


The bright, crisp colors of summer begin to fade with the arrival of fall, revealing a riot of new colors on our foliage. These colors range from vivid reds and golds to deep oranges and browns before finally falling from the trees. For decades, travelers have chased the rainbow of colors across the United States in hopes of taking breathtaking photos or just for personal gratification.

Weather conditions throughout the year contribute to autumn colors but the primary driving factor is day length. Numerous warm, sunny days and cool evenings seem to be the harbingers of the best fall colors. Idyllic weather conditions allow trees to produce significantly higher volumes of sugar in leaves and the cool nights slow sugar export.

Surplus leaf sugars stimulate anthocyanin (red and purple) pigment production. Carotenoid (yellow and gold) pigment levels tend to remain steady throughout the growing season though masked by chlorophyll until autumn. Chlorophyll In addition to sunshine, soil moisture also contributes to leaf color. Predictors of vibrant fall color: spring (warm, wet); summer (warm/hot with sufficient rain); fall (warm sunny days, cool nights). Delayed spring showers or an extended summer drought can delay fall color for weeks.

2017 GotNature Fall Color Fig 1a

Color change is initiated in the northeastern United States before continuing southward and can be species-specific. Aspens and hickories (primarily bronze, gold, and yellow), dogwood and oaks (ranging from deep red to dark brown), and maples (most often bright red to yellow-orange) represent the wide range of hues. In contrast, some species (elm) rarely exhibit any fall color. The map below, currently pinpointed to November 5th, can be used to visualize progression of fall color nationwide. For details of fall color across the nation, a fall color hotline 1-800-354-4595 has been created by the Forest Service to give travelers updates.

Fall foliage prediction act, smokymountains.com.

References:
Figure 1- Fall leaf photo
Figure 2- Fall foliage prediction act, smokymountains.com

Resources:
Autumn Leaves – what influences the color? – Got Nature?, Purdue FNR-Extension
Why Leaves Change Color, The Education Store, Purdue Extension
Why Leaves Change Color, USDA Forest Service, Northeastern Area

Shaneka Lawson, USDA Forest Service/HTIRC Research Plant Physiologist/Adjunct Assistant Professor
Purdue University Department of Forestry and Natural Resources


Red maple tree, fall red leaves. Photo by: Lenny Farlee

Red maple tree with leaves turning red in fall. Photo by: Lenny Farlee

​The calendar flipping over to October is a reminder the annual Autumn leaf color display is on its way. The perennial question is “how will the color be this year?” Predicting the quality of the fall display requires weighing several factors that may vary over time and across the landscape. In general, Indiana started the growing season wet and is ending it dry. The good growing conditions early this year have produced abundant leaf area on many trees. As we have dried out late in the season, some trees are experiencing stress that may cause leaves to turn color and drop early, or to simply turn brown. Drought may also delay the color change by a week or more in some cases. Leaves that were attacked by insects or disease may also drop early or provide very little color. I noticed Japanese beetles seemed to be more active than normal this year, skeletonizing leaves on preferred plants like linden and Virginia creeper. Local weather patterns can also influence color intensity in a positive way. Sunny days and cool nights late in the summer and early fall can enhance the production of anthocyanin – a pigment produced in some trees that provides bright red, maroon and purple tones to the fall color palate.

Hop hornbeam tree with yellow fall leaves. Photo by: Lenny Farlee

Hop hornbeam tree with yellow fall leaves. Photo by: Lenny Farlee.

This brings us to another variable: different species of trees may produce different colors, timing, and duration of fall color. Some species like sassafras, sumac, black and sweet gum, and sugar and red maple are famous for bright fall color. Some species like elms, buckeye and walnut may simply turn brown or drop early with little color display. Different individual trees may also vary due to genetic differences, growing conditions and tree health. For example, some sugar maple located in open areas or on the edge of a woodlot, receiving lots of sunlight, may regularly produce vibrant oranges and reds, while nearby sugar maple in the shade of the forest will turn a subdued yellow, lacking the sugar reserves produced by their neighbors in the sun.

Leaf color change is also the result of a very predictable process based on the longer night period as summer slips into fall. The production of green chlorophyll pigments slows and finally stops as the nights become longer and cooler, exposing the yellows and oranges of carotenoids and reds and maroons of anthocyanins. This process also starts forming a zone of separation between the leaf and branch that ultimately brings the leaves to the ground, often with the help of wind and rain.

My best answer to those asking for a fall color prediction is another set of questions: how was your weather, what species of trees do you have, and how much sunlight do they receive?

Resources:
Why Leaves Change Color, The Education Store, Purdue Extension
Why Leaves Change Color, USDA Forest Service, Northeastern Area
Fifty Trees of the Midwest App for the iPhone, The Education Store
Native Trees of the Midwest, The Education Store
Shrubs of Indiana CD: Their Identification and Uses, The Education Store
Shrubs and Woody Vines of Indiana and the Midwest: Identification, Wildlife Values and Landscaping Use, The Education Store
Trees of Indiana CD, The Education Store

Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue Department of Forestry and Natural Resources


Tree Planted in BackyardSpring and Fall is prime time for improving your property with new trees. They provide many benefits which everyone can share. Trees mean more attractive landscapes, lower energy bills and a healthier environment. However, just planting a tree without some thought and planning can create a liability rather than an asset to your site. Wise planning is essential to ensure the new trees meet your design needs and functional solutions as well. Follow these basic tips to get your tree started right and make it a long-lasting sustainable planting. For more information, download the free publication Tree Installation: Process and Practice.

Right Tree-Right Place.
Location, location, location! Planning before planting can help ensure that the right tree is planted in the right place. Proper tree selection and placement enhances your property value, prevents costly and sometimes unsightly maintenance with trimming, and lowers the risk of damage to your home and property. In some instances, trees are the innocent victim of poor planting locations and must be removed. Always allow room for growth! Also, consider native trees or those trees with fewer pests which can attack your tree. Large trees include Kentucky Coffeetree, Bur Oak and Hardy Rubber Tree. Medium-sized trees can include Japanese Pagoda Tree, Sourwood, Katsura Tree and Golden Raintree. Finally, for areas with less room, consider Serviceberry, Ironwood, Amur Maackia or Hop Tree. These are just a few of the many trees which can be chosen for your situation.

Look Up, Look Down, and Look All Around!
Regardless if the planting is in the front yard or the back yard of the home or business, be sure there will be no interference with utilities; Call 811 before you dig. It will prevent costly mistakes and maybe a life. In addition, if the tree is going to be planted along the street, typically, there is an ordinance requiring a permit to plant in the right of way. This helps Urban Forestry administration keep up the street tree inventory and allows the ISA Certified Arborists on staff a chance to offer free advice to help in the planting decisions.

It Comes from Good Stock…
Choose the tree twice, meaning get the right species for your location; then, make an informed choice on the nursery stock. Be sure the function of the tree is understood and choose the right tree for the location. Shade? Flowers? Screening? Sound Barrier? Trees can be used as tools to work for you on the site. “You get what you pay for” applies to nursery stock as well. Purchase plant material from a reputable source and get a professional opinion on the tree species for your application. One hint, if it is a fast growing tree, it probably won’t last long. See our video for tree selection tips.

This Hole is a Home!
It is a permanent home for the trees… understand the planting site prior to planting. Determine soil type and pH, drainage and exposure to the sun. If the tree isn’t naturally suited to the planting place, it doesn’t have a chance. Planting depth is a major tree planting concern. Be sure to find the “root flare” when establishing the final grade of the tree. Drainage is crucial to survival. Use the two-hour test. Dig the hole, fill it with water. If the hole is empty upon returning, there is suitable drainage for any tree. Plant the tree properly and at the proper depth, you only get one chance… Don’t dig a $10 hole for a $100 tree. See our video on tree planting tips.

Keep Good Care of the Investment.
Once the tree is in the ground, take good care of it. At least an inch of water per week to keep it growing vigorously, apply clean, hardwood mulch on the root zone to keep soils cool and moist, but never exceed three inches in depth. Remember to remove any tags on the tree and don’t forget to remove the twine from around the trunk. Don’t worry about the fertilizer at planting time, wait until next year, after the tree has gotten settled in to its new home. Enjoy your new addition to the home and landscape!

Resources:
Tree Selection for the “Un-natural” Environment, The Education Store, Purdue Extension
Tree Support Systems, The Education Store, Purdue Extension
Tree Installation: Process and Practices, The Education Store, Purdue Extension
Planting Your Tree Part 1: Choosing Your Tree, video, The Education Store, Purdue Extension

Lindsey Purcell, Urban Forestry Specialist
Purdue University, Department of Forestry and Natural Resources


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