January 2008

Welcome to this issue of the Hardwood Tree Improvement and Regeneration Center E-newsletter. The HTIRC is committed to enhancing the productivity and quality of Central Hardwood Region trees and forests for the economic and environmental benefits they provide. Scientists at the HTIRC are using conventional tree improvement breeding as well as molecular and genetic technologies to improve the wood quality, growth characteristics, and insect and disease resistance of trees like black walnut, black cherry, red and white oaks, butternut and American chestnut.

Research in tissue culture, tree nursery practices, tree plantation establishment and management, and Central Hardwoods silvicultural systems is aimed at increasing the regeneration
success rate for high quality hardwood trees and forests. Some interesting and unusual research areas include examining the potential for propagating trees with “figured” wood: birds-eye maple or curly walnut; and breeding trees that will be an economical source of bio-fuels.

Twice per year, we will attempt to provide interesting and useful information on Central Hardwood trees and forests, as well as sources for additional information and assistance.

Please pass this newsletter along to others who may enjoy or benefit from the information provided. If you would like a closer look at the HTIRC, please visit our web site at: http://www.htirc.org

A Recipe for Early Success in Tree Planting

Brian Beheler, Lenny Farlee,
and Jim Mckenna, HTIRC

The management a tree planting receives in the first few years can be a good predictor of how successful it will be in terms of growth and survival. The work of researchers and over 15 years of personal experience in planning and observing tree plantations bears this out. Plantings with no management or ineffective management practices often result in landowners and resource managers frustrated by poor seedling survival and performance due to competition, predation, or compatibility problems.

•  Competition: We are often trying to introduce trees into environments that have other plants that can grow more quickly or occupy resources more aggressively than our seedlings. Often our planting area has previously established vegetation occupying the site. If we use a mixture of trees with large differences in growth rate, we may be dooming some of those species to failure.

•  Predation: Seedlings from nurseries often have nutrient-rich growth that is very desirable to a variety of herbivores, including deer, rodents and rabbits. The species we wish to grow may also be preferred foods of certain wildlife, resulting in selective feeding on our plantings. Animals like deer and birds can also do physical damage to seedlings through rubbing and perching, resulting in broken stems and branches. Insect or disease damage is also a threat.

•  Compatibility: Not correctly matching our tree species to the conditions of our site may result in long-term poor performance or failure of the planting. Soil characteristics, moisture levels, temperature extremes, flooding potential, and available sunlight are just some of the variables that need to be considered when selecting tree species for specific planting sites.

Competition with our seedlings needs to be addressed before, during and after planting. Before plantings are installed, control vegetation on the site. This operation can be accomplished with tillage, herbicides, barriers or a combination of these. If undesirable woody plants are present, manual or mechanical cutting and herbicide treatment to control sprouting will be needed. Some particularly tough plants, like tall fescue, may require you start the control measures almost a year before you will plant the seedlings. Once you have controlled the undesirable plants, you may want to put a cover crop in place to prevent annual or perennial weeds from re-invading the area. Cover crops should not present serious competition to tree seedlings but provide enough ground-shading to prevent other plants from taking over the site. Short clovers, winter wheat or rye, oats, rye grasses, or a combination of these, are a few cover crops that could be used in plantings. Some method of weed control needs to be applied at or near the time of planting and maintained for the next two to four years, depending on the weed competition intensity and growth rate of seedlings. Herbicides are generally the most economical weed control method for typical conservation plantings. Be sure the herbicides used are labeled for that application and safe for the species in your plantings. Some materials, like Glyphosate, cannot be sprayed on leaves or expanding buds of any plant species without damaging or killing the plant, so a directed spray or shielding seedlings from the spray may be required. Always read and follow label directions when using herbicides.

An herbicide program the HTIRC uses for our fine hardwood plantings follows:

If using a coulter-and-shoe tree planter, we do a burn-down with Glyphosate (Roundup) in the fall prior to weed dormancy or from 2 weeks to one day before planting in the spring.  After the trees are planted we spray in a 2 foot wide band on each side of the tree row a pre-emergent mix of Oryzalin (Surflan) at 2-3 qt/acre and Pendulum Aquacap (3 qt/acre).  We try to wait to spray after the planting has had a rain event to seal the planting slit, but sometimes, due to distance from campus, we must spray the same or next day after planting, so care is taken to make sure the planting slit is sealed and roots are in good contact with the soil to prevent herbicide contact with the seedling roots. This mixture will usually provide good weed control until late July. 

We typically have 4-6 species of weeds that are not controlled with this mixture (mares-tail, cocklebur, thistles, goldenrods, ragweeds) so we usually do a mid June application of Transline (12 oz/acre).  If we have grass problems we will use Envoy. We also have a dome-covered sprayer with a controlled droplet applicator which allows us to spray Gylphosate on plantations in late spring or early summer at a lower expense than Transline and Envoy, but care must be taken to avoid any Glyphosate contact with the seedlings.

If we auger holes for the tree planting, we have found that tilling the planting rows in the fall prior to planting works very well.  Once the trees are planted, we use the pre-emergent herbicides listed previously.  This usually provides the best weed control. 

We have been spraying for the first 4-5 years, depending on growth, usually in late March with Glyphosate*, Oryzalin or Simazine, and Pendulum Aquacap.  We typically do one mowing in early to mid July before too much pollen or seed heads appear on the summer weeds.  On plots that have invasive woody plants, we have been using a weed eater with a metal blade to cut them in the summer then spray the new sprouts with Glyphosate (Round-Up) in late summer to early fall before they go dormant. 

*Glyphosate is used on seedlings in March since seedlings are dormant at this time. If seedlings are beginning to break bud or showing other signs of active growth, do not allow Glyphosate spray to contact seedling buds or leaves. Some species like cherry and tuliptree may break bud earlier than oaks and walnut, so careful observation is needed. If in doubt, do not use the Glyphosate or protect seedlings from the spray.

This is an example of an intensive weed control program providing low competition growing conditions to help seedlings become established. Many plantings could use a program like this for two to three years after planting and obtain good results. This is not a recommendation for your specific planting site, as soils, weed species, planted species, management systems, and changes in herbicide labeling and materials available through time will determine what materials and methods will work best for you. Consult with experienced professional foresters in your area as you develop your weed control program.

Plantation design also has an impact on competition in the planting. Recognizing the relative growth rates and light requirements of the trees and shrubs you plan to plant will help you design a more successful plantation. For example, if you are interested in growing oaks on a highly productive site, you may not want to plant tuliptree or black cherry seedlings near the oaks, since they will probably out-grow them and dominate the site. Wildlife shrubs could be planted on the outside edge of the plantation to allow for longer exposure to sunlight as the tree species grow taller in the interior of the planting. Quick crown closure and shading of the planting site can also be an effective weed control method. Plantings can be designed to encourage straight stems and natural pruning of lower branches, maintenance of a diversity of species, production of abundant wildlife food, and a variety of other objectives, depending on the spacing and arrangement of seedlings in the planting. Selection of high-quality nursery stock that is capable of good growth following planting will also provide a competitive advantage for your trees. Consult a professional forester to help you plan the best design for your planting area.

The HTIRC has a series of publications providing guidance for planting and managing hardwood trees.

We will cover predation and compatibility issues in a future article. If you would like to explore these or other tree planting issues further, refer to the above publications or visit these sites:

Purdue University Forestry and Natural Resources Extension publications: http://www.fnr.purdue.edu/extension/publications.shtml

Forest Landowners Guide to Internet Resources: http://na.fs.fed.us/pubs/misc/flg/

Mention of company or trade names does not imply endorsement by the HTRIC or Purdue University .


A harvested soybean field is easily planted to hardwood trees and has minimal early weed competition. Pre-emergent herbicides, cover crops, or weed barriers are easily to apply as well.

butternut07 017

An example of effective herbicide weed control on a new tree plantation. Weeds between tree rows are only of concern if they grow tall enough to shade seedlings or are a noxious weed that must be controlled.

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Clover cover crop between rows on a hardwood planting, combined with occasional high mowing, helps keep less desirable vegetation from overtaking the planting.

Preventing Herbicide damage to B-nut at SEPAC

Using a dome sprayer with Glyphosate for mid-season weed control. Care must still be exercised to avoid spray contact with low leaves

Fertilization of Bare Root Hardwood Tree Seedlings at Planting for Improved Growth

Douglass Jacobs, Francis Salifu, HTIRC

Past research has shown mixed results for the use of conventional fertilizers in the first one or two years of bare root hardwood tree seedling plantings. Seedling growth response in some cases was negligible or negative. First year fertilization was also discouraged due to the capacity of annual weeds to respond quickly and aggressively to the added fertility and create additional weed control problems in plantings. For these and other reasons, early fertilization of bare-root tree seedling plantings is rarely recommended by professional foresters.

A recent study suggests the use of controlled-release fertilizer applied directly to the planting zone of bare-root seedlings may provide an opportunity to boost seedling growth over the first two growing seasons . Controlled-release fertilizers are formulated to gradually release nutrients over a period of time determined by fertilizer formulation, temperature, and moisture. This gradual release of nutrients allows for placement of fertilizer in the rooting zone of the seedling and provides added nutrient availability for up to two growing seasons.

The study, by Douglass Jacobs and Francis Salifu of the HTIRC, Purdue University Department of Forestry and Natural Resources , and John Seifert , formerly of the Southeast Purdue Ag Center, Purdue University Department of Forestry and Natural Resources and now State Forester, Indiana Division of Forestry , looked at the growth response of white ash, tuliptree, and black walnut seedlings treated with 5 different rates of controlled-release fertilizer and no fertilization. One year old bare-root seedlings from the Indiana state tree nursery system were planted in southeastern Indiana in April of 2002 on land formally in agricultural crop production. Six rates of a controlled-release fertilizer, Scotts Osmocote Exact Low-Start 15N-9P-10K plus minors, applied at 0, 15, 30 45, 60 and 75 grams, which corresponds to 0, 0.53, 1.06, 1.59, 2.12, and 2.65 ounces by weight, were placed in a line of 4 to 6 inches in the bottom of the planting trench just below the root system of each seedling. The site had chemical weed control applied before and during the study period to prevent weed competition. An electric fence was installed to prevent browsing by deer.

Tests indicated the fertilizer was released over a 15 to 18 month time period, with about half of the nutrients made available in each growing season.

Seedling survival was greater than 90% across all treatments, with tuliptree showing the lowest survival rate. Both height and root collar diameter growth increased in the first year with increased rate of fertilizer up to the 60 gram or 2.12 ounce amount, but dropped at the 75 gram or 2.65 ounce amount. In the second growing season there was no significant difference in height growth between the different fertilizer rates and no fertilization, but the fertilized seedlings did produce larger root-collar diameter growth, with the 60 gram or 2.12 ounce amount the optimum rate once again.

First year growth results

Second Year Growth Results

WA –white ash, YP – yellow-poplar or tuliptree, BW – black walnut One foot =30.48 cm, one inch=25.4 mm. Different letters on top of the bars represent statistically different results.

There were also significant differences in growth rate between the three tree species. Black walnut lagged behind white ash and tuliptree in height and diameter growth over both growing seasons. Tuliptree and white ash were able to grow in height between three and four times faster than black walnut over the two year study. The rapid early growth of tuliptree and white ash across all treatments as compared to black walnut has some important management implications, if that height advantage is maintained in the future. Unless black walnut height growth accelerated to the growth rate of the ash and tuliptree, it would have little chance of maintaining itself in the plantation without some management activity like thinning or crop tree release.

The results of this study suggest that fertilization with controlled-release fertilizer may improve early growth rates of hardwood trees. An increasing rate of fertilization improved growth up to the 2.12 ounce rate, but growth decreased at the highest rate, suggesting additional fertilizer is not beneficial or even detrimental to growth. This fertilizer was a controlled-release low-start 15N-9P-10K formulation. If you use a controlled-release fertilizer with different nutrient analysis, you will need to adjust the rate of application to match this treatment in terms of total N, P, and K applied. For example, if the fertilizer analysis was 30N-18P-20K, you would apply 1.06 ounces to mirror the 2.12 ounce rate used here. Consider carefully the species mix in the planting. Trees with slower early growth, like black walnut and oaks, may not be able to compete with quick starters, like tuliptree, ash, and black cherry. Additional studies are planned to look at longer-term impacts of controlled-release fertilizer on hardwood plantings, but the results from this study indicate it’s a practice that may be beneficial for establishment of hardwood seedlings.


The original research paper is available here: http://www.agriculture.purdue.edu/fnr/HTIRC/pdf/Jacobsetal.2005.pdf

Information on Scotts controlled-release fertilizer: http://www.scottsprofessional.com/en/group/11

Mention of company or trade names does not imply endorsement by the HTRIC or Purdue University .

Chrysler Partnership with Purdue University Taps Environmental Powers of Poplars

Auburn Hills, Michigan – Article by Max Gates, Chrysler LLC

  • Hybrid Poplars Tested at Rural Indiana Site
  • Faster Phytoremediation – Using Plants to Clean Up Pollution
  • Purdue Researchers Also Developing Poplars for Better Biofuels

Chrysler LLC is partnering with Purdue University to test the powers of poplar trees to clean up environmental spills and, when fully grown, become a source of improved renewable biofuels.

In the first stage of the project, plots of hybrid poplars have been planted at Peter’s Pond, the site of an environmental cleanup being conducted by Chrysler in rural central Indiana south of Kokomo.

Chrysler’s collaborator on the project is Purdue Associate Professor Rick Meilan who is looking for ways to greatly improve hybrid poplars’ ability to clean up contaminants in the environment.  Meilan is also part of a team researching altered varieties of poplars that would improve the process of turning harvested plants into bio-ethanol for use in Flexible Fuel Vehicles.

“This project supports our most important environmental principles at Chrysler: respect for the environment, returning our former sites to productive use, and promoting the use of clean, renewable, American-made biofuels such as ethanol,  in our vehicles,” said Deborah Morrissett, Vice President of Regulatory Affairs at Chrysler.

Chrysler has invested more than $10 billion over the past two decades to either refurbish existing sites or to prepare vacant sites for productive use.

Chrysler has also produced nearly two million Flexible Fuel Vehicles (FFVs) capable of running on E85 (85 percent ethanol), gasoline or a mixture of the two fuels.  The company will produce an additional 500,000 FFVs in 2008.

Meilan is part of a research team that is developing altered poplars with much greater ability to take up contaminants.  In their research, Meilan and colleagues found that engineered poplars removed more than 90 percent of pollutants such as trichloroethylene (TCE) from a test solution in one week, compared with just 3 percent of pollutants removed by unaltered poplars. TCE, a commonly used solvent, was found in the soil and groundwater at Peter’s Pond.

In addition, the specially-engineered poplars were able to break down the pollutants 100 times faster than the unaltered poplar.

Meilan will plant the specially-engineered poplars at the Peter’s Pond site next spring. Their ability to remove TCE from the soil will be compared with the hybrid poplars already planted at the site.

The process of using plants to absorb pollutants from the soil, known as phytoremediation, should work well at Peter’s Pond since the remaining pollutants are within 10 feet of the surface and readily accessible to poplars’ roots.

“Peter’s Pond is the perfect place to take this process out of the lab and test it on a field-sized scale,” said Meilan.  

Meilan and colleagues are also developing hybrid poplars that can be refined into ethanol more easily.  One of the barriers to producing ethanol is lignin, a compound that gives the plant strength.  Lignin blocks access to cellulose, the compound in the plant that is the primary source of sugar for refining into ethanol.  By developing poplars with modified lignin, Meilan hopes to make renewable ethanol faster and cheaper to produce.

If the process works out, it can be readily adapted to many other parts of the world, Meilan noted.

 “Poplars grow across a wide geographic range and in many different climates,” Meilan said.

“People have had their eye on the poplar for a long time.”

Chrysler’s FFV Lineup

For the 2008 model year, Chrysler offers 11 products with the E85 Flexible Fuel option:

  • Dodge: Dakota, Ram, Durango, Avenger, Grand Caravan
  • Chrysler: Aspen, Town & Country, Sebring sedan and convertible
  • Jeep: Grand Cherokee, Commander

Chrysler also promotes the use of biodiesel, another clean, renewable, American-made alternative fuel. Jeep Grand Cherokee and the Dodge Ram and Sprinter diesel vehicles are all approved for use with B5 (5 percent biodiesel) fuel and are delivered to customers running on B5.

History of Peter’s Pond

The property known as Peter’s Pond was once used for gravel mining operations.

In the mid-1960s, oils from the Chrysler Transmission Plant in Kokomo were disposed of in three abandoned gravel pits.  Cleanup of the site was begun in the mid-1980s, and Chrysler continues to monitor the groundwater and soil today.

Two small areas on the site still have small amounts of pollutants.  Chrysler proposed the phytoremediation system using poplars to polish the remaining pollutants from the soil and groundwater.

Ultimately, the plan is to return the Peter’s Pond site to farming, a major economic activity in central Indiana.

Improving White Oak for Timber and Wildlife Benefits

Keith Woeste, Lenny Farlee, Jim McKenna, HTIRC

White oak ( Quercus alba ) is one of the most important trees in the Central Hardwood region. It is a common, and in many areas a dominant species in native forests and ranks high in terms of total volume of standing wood and also annual harvest volume. It is one of the most valuable timber trees in the eastern US, with uses including high quality veneers, flooring, furniture, water-tight cooperage for barrels, blocking and pilings, and high quality fuel wood. White oak acorns are a favored food source for many species of wildlife, including wild turkey, squirrels, and deer. White oak is also one of the longest-lived hardwood trees, with ages in excess of 400 years possible. These characteristics have produced interest in growing and managing white oak for timber production and wildlife management objectives. Due to longstanding problems related to the natural regeneration of oaks, there is strong interest in regenerating oak by planting. Surveys of forest tree nurseries concluded that nursery managers want to grow genetically improved hardwood planting stock, but they are frustrated by the limited availability of improved seed. It is expected that there will be an even higher demand for improved seed in the future. Many forest landowners in the Midwest place a high value on trees that improve wildlife habitat. Although many native oaks and especially white oak produce excellent mast for wildlife, most planted white oak seedlings will not begin to bear acorns until they are well over 20 years of age, and often not until they are more than 50 years old. As a consequence, some forest owners are now planting heavy-masting, non-native oak species with poor timber quality, sawtooth oak being one example. The long-term impacts of planting non-native oaks in the Central Hardwood region are not known, but other exotic tree and shrub species have become environmental problems.

Purdue University researchers built a national reputation over the past four decades for improvement of hardwoods, especially black walnut, but there has been no real effort to improve white oak, one of Indiana’s most valuable hardwood species. Fortunately, in 1981, the tree improvement specialist for the Indiana Division of Forestry identified 63 white oak mother trees representing the entire state of Indiana. Seedlings from these mother trees were planted in replicated trials at Jasper-Pulaski Nursery, Harrison-Crawford State Forest , and Starve Hollow Natural Area. The trees (over 5,000 in number) are now mature, and were measured by Scott Rogers , a MS student in FNR in the winter of 2005-2006 as part of his thesis research. Rogers has analyzed the data to identify superior white oak parents for propagation of two types of seed orchards: one for superior white oak timber and one for early-masting (seed production) for wildlife. In 2007 the best white oaks from the 1981 plantings were identified using statistical analysis, and Rogers has propagated them onto oak rootstocks under the direction of Jim McKenna , an HTIRC biologist with extensive experience grafting white oak and other fine hardwoods. The grafted trees were grown in the greenhouses at the Wright Center , a facility for research, education and engagement owned by the Purdue University Department of Forestry and Natural Resources (FNR) , and hardened off in a shade house at the same location. After holding them over winter, we propose to plant the grafted white oak trees into seed orchards.

Trees selected for superior timber traits will be planted onto a high quality oak site at the Cunningham Farm , a property near campus owned by FNR; trees selected for early acorn production will be planted at Martell Forest . Duplicate orchards have been propagated for the state of Indiana to manage. Although the seed orchards for improved timber and early-masting oaks will be kept separate, there is no evidence that early-masting oaks have unacceptable or even reduced value as timber trees (Kim Steiner, personal communication). This remains an important area for future research. Because the white oaks selected for the improved seed orchards are mature, grafted trees propagated from them are expected to produce flowers and seeds quickly, typically within four years. Thus, we will begin delivering improved white oak seeds to the State tree nursery in four years, and landowners will have improved white oak seedlings 18 months later. Seed production from the orchards is likely to increase every year for at least the first 20 years and could reach 400,000 acorns per year.


1) We propose four seed orchards of select, native white oak adapted to Indiana. Once they reach maturity, the orchards are expected to provide a large percentage of the white oak acorns needed by the State Nursery, which grows them for forestation and sells them as low-priced, improved seedlings. Seedlings from the select, early-masting trees will bear seed at a considerably younger age than unimproved white oaks.

2) The orchards on Purdue property will be the starting point for second-generation orchards that will improve the timber value and early acorn production of white oaks even more.

3) When the white oak seed orchards come into production, any landowner who buys white oak from the State Tree Nursery will begin receiving benefits: trees with increased timber value and trees with increased value for wildlife.

4) When seeds of precocious white oaks are available at nominal cost through the State nursery, landowners who place a high value on wildlife will have a much stronger incentive to plant native oaks with value as fine hardwoods as part of their management plan . At present, the only early-masting oaks on the market are unimproved, and either expensive or non-native species that have low value for timber.

The expected results from use of these selected white oak trees is an 8% to 10% increase in the rate of height and diameter growth, as well as improved stem form, for the timber selections. The early seed production selections should have twice as many trees bearing acorns by the age of ten, as compared to nursery-run seedlings. These are expected results that will require testing over a period of years to confirm. This effort to produce native white oak seedlings selected to provide desirable characteristics should help this exceptional tree remain one of the most important hardwoods in the United States and a beneficial part of many tree plantings.

Selection of superior trees in the white oak mother tree orchard.

Grafted white oak selections for planting in seed orchards.

Getting Ready for Tax-Time

If you have done reforestation tree planting or sold timber on your property in 2007, you may be able to reduce your income tax liability. Plantings done for timber production may qualify for a 10% tax credit and amortization of expenses. Timber sale income may qualify for capital gains tax rates and some of the income can be offset by establishing a cost basis for the timber and assigning a depletion allowance, thus reducing tax liability. Here are some resources that can help you understand your options.

An excellent reference for tax management for forest landowners is the National Timber Tax website: http://www.timbertax.org

If you want to learn more about tax issues associated with tree planting, refer to the HTIRC publication Financial and Tax Aspects of Tree Plantings:
Some publications that can help you with forest management and timber sale tax issues include:
How to Treat Timber Sale Income: http://www.fnr.purdue.edu/extension/pdfs/faq3.pdf
Minimizing Federal Income Tax for Forest Landowners: http://forestry.msu.edu/extension/ExtDocs/NCR343.pdf