The Processing And Properties Of Pine Wood Chips

Over the past decade, there has been a lot of talk, debate and research conducted on the discovery and use of alternative substrates and substrate components. More information has been generated in recent years than at any other time since the 1960s and ’70s, when the first peat-lite mixes were introduced as substrates for greenhouse crop production.

The most discussed and researched new material/component has been the use of freshly processed pine wood/trees. These pine tree substrates (PTS) have proven successful when used in greenhouse and nursery mixes, mainly as a peat/bark-extender or peat/bark-alternative. It has been suggested that the use of these wood components in peat-based mixes could deem perlite unnecessary due to the aeration (increase in porosity) that the wood components create in the substrates; however, no specific information or research has fully investigated this claim.

 

Alternatives to perlite have been thoroughly investigated over the years primarily because perlite is the most expensive substrate component (by volume) due to the costs associated with mining, heating and transporting the material. While perlite does a wonderful job as an aggregate in peat-based mixes, its particle size can be variable (affecting the porosity in mixes), and the well-known dust it emits during handling can be a nuisance for workers.

In 2010, researchers in the Horticultural Substrates Laboratory at North Carolina State University (NCSU) began investigating the engineering and processing variables that influence the consistency and ability to reproduce traditional and alternative substrate components. These researchers (Brian Jackson and Bill Fonteno) began a different approach to substrate research, one that “began with the end in mind.” They focused on how to better understand the engineering and processing of pine tree substrate components to be better able to recreate them, utilize their potential and make them into more “value-added” components. Specifically, one of the main goals was to create a wood aggregate that could be an effective and cheaper alternative to perlite.

Pine Wood Chips Versus Perlite

Pine tree substrate materials have traditionally been produced from freshly harvested loblolly pine (Pinus taeda) trees that were chipped and then further processed in a hammer mill through screen sizes ranging from 3/16- to 3/8-inch. The resulting end product contained a mix of particle sizes and shapes, mostly being a fibrous-like material. It was the mix of fibrous particle sizes that gave the material water-holding properties similar to some peat and pine bark substrates.

To produce a non-fibrous wood component, it was discovered that changing the size of the coarse wood chips (using different machines to chip the pine logs) and adjusting the moisture content of the wood chips prior to hammer-milling yielded consistent non-fibrous small pine wood chips (PWC) that can be used specifically as substrate aggregates. When coarse wood chips are processed in a hammer mill through a ¼-inch screen, the end product is PWC that has the same particle size as a coarse-grade perlite. Because different aggregate sizes are needed for different substrate mixes (propagation, plugs, bedding plant flats, one-gallon pots, etc.), the screen size used to process the wood chips can be changed to produce smaller wood chips. So, like perlite, different grades/sizes of PWC can be constructed.

A full range of laboratory testing was conducted on PWC to determine the exact properties of this material. Particle sizes, moisture release curves, drainage profiles, hydration efficiency and physical properties including total porosity, air space, container capacity and bulk density were determined. The PWC were tested against perlite in all studies to compare the differences and/or similarities between these two aggregates.

Both aggregates were amended to peat at rates of 10, 20 and 30 percent, which cover the general range of amendment percentages that growers would use in their greenhouse mixes. At each aggregate rate tested, there were no differences in the substrate physical properties. Higher rates (>30 percent) were also tested and at the higher rates, more air space is found in mixes containing PWC compared to perlite.

After thorough and repetitive testing, results remained consistent that PWC can replace perlite in a peat substrate with the same resulting change to substrate porosity (air and water percentages). Even though perlite can be completely substituted with PWC with no change in physical properties, the addition of 3 to 5 percent perlite to mixes may still be needed since the general public (consumers) has the perception that the white particles of perlite are actually fertilizer.

Cost Performance, Uses And Production Of Pine Wood Chips

The estimated cost of PWC, including the acquisition of pine trees, equipment to process the trees, and actual manufacturing (energy, man hours, etc.) will be 40 to 50 percent cheaper than perlite. Further assessment on the economics of PWC commercialization is being investigated.

Since the development of PWC in 2010, dozens of plant growth trials have been conducted to investigate their use as aggregates in greenhouse substrates. These plant trials included numerous summer and fall annual species, perennials, vegetable transplants and seasonal floriculture crops (mums and poinsettias). General observations during these trials show that the PWC aggregates do not decompose during crop production (no shrinkage), and they barely change color (they remain the yellow color of fresh pine wood) if at all. Another observation made numerous times over the past several years is the quality of the root growth of plants grown in mixes containing PWC and other wood substrate components.

University researchers, substrate manufacturer R&D personnel and some growers have independently commented on the exceptional root growth that many plants will have. There are several possibilities for why this is occurring but no solid evidence is currently able to explain it fully. Additional research results will be released in the near future to cover important cultural information about the use of PWC in greenhouse crop production, including fertility practices, lime/pH modifications, plant growth regulator efficacy and aging/phytotoxicity concerns.

Despite the traditional uses (pulp, paper, timber, fuel, etc.) and more recent uses (wood pellets, biofuels, etc.) of pine trees in the United States, it is still believed that pine wood is a reliable source of sustainable greenhouse substrate components in the foreseeable future. The Southeastern United States is one of the most abundant wood-producing regions in the entire world and production (acreage) continues to be more productive, thanks to innovations in tree genetics and silviculture practices.

It has been mentioned in the past that a grower, consortium of growers, substrate manufacturer(s), or other private entrepreneurs could intentionally plant pine trees for the specific purpose of growing them for use in horticultural substrates. Since the ideal tree age for processing is between 12 to 14 years (depending on planting density, soil type, fertility, etc.), the turnover in acreage would be relatively quick. It is unknown at this time how much PWC or other pine wood components could be produced from an acre of land planted dense enough to be uniformly harvested at one time (which is unlike current pine management practices). Much work continues at NC State University at the Substrate Processing and Research Center (SPARC), constructed in 2014, to better investigate the engineering and utilization of traditional and alternative substrates.

 

 

 

 

 

 

Topics:

Leave a Reply

More From Crop Inputs...
Suzanne Wainwright-Evans

February 8, 2016

Register Now For Biocontrols USA 2016 Workshop

Biocontrol is becoming a mainstream part of growing plants commercially. Every good program starts with quality products and a good supply chain. Register now to join us from 1:00-4:00 p.m. on March 4, following the conclusion of the education program at the Biocontrols USA 2016 Conference & Expo in Monterey, CA for a special event that will help you improve your biocontrols program. In this informative, real-world workshop led by biocontrols expert Suzanne Wainwright-Evans, owner of Buglady Consulting, you’ll learn: The key players that are producing beneficials How to check product quality once you get them The latest trends and practices growers are using to implement beneficials into their programs Important pitfalls to avoid. A roundup of the current biocontrol research that can help you be more successful in your production practices this season. Wainwright-Evans, a pest management specialist, has been involved in the green industry for more than two […]

Read More
Gotham Greens Queens

February 8, 2016

Gotham Greens Opens Newest Greenhouse In Queens, NY

The new facility, which was partially funded by grants based on reduced energy consumption, nearly triples Gotham Greens’ overall production capacity in New York.

Read More
Travis Higginbotham

February 8, 2016

Biocontrols And Next-Generation Production

Biocontrols are becoming much more established in greenhouse production. In some cases, it’s the next generation of growers that’s helping to support the adoption of this next generation of pest control. Travis Higginbotham, R&D Manager for Battlefield Farms, in Rapidan, VA, is a great example. Brought on in 2014, he is helping Battlefield take the next step in product development, as well as become more efficient as a business and adapt to new technologies and demands from their customers with a more proactive approach. Higginbotham will share information on Battlefield’s nematode program at the Biocontrols USA 2016 Conference and Expo, March 3-4, 2016 in Monterey, CA. We asked him about the details involved with building a new biocontrols program, as well as the future of sustainability in greenhouse production. Q: What are the differences in costs involved in using biocontrols? What costs should growers consider, aside from the hard costs […]

Read More
Latest Stories
Suzanne Wainwright-Evans

February 8, 2016

Register Now For Biocontrols USA 2016 Workshop

Biocontrol is becoming a mainstream part of growing plants commercially. Every good program starts with quality products and a good supply chain. Register now to join us from 1:00-4:00 p.m. on March 4, following the conclusion of the education program at the Biocontrols USA 2016 Conference & Expo in Monterey, CA for a special event that will help you improve your biocontrols program. In this informative, real-world workshop led by biocontrols expert Suzanne Wainwright-Evans, owner of Buglady Consulting, you’ll learn: The key players that are producing beneficials How to check product quality once you get them The latest trends and practices growers are using to implement beneficials into their programs Important pitfalls to avoid. A roundup of the current biocontrol research that can help you be more successful in your production practices this season. Wainwright-Evans, a pest management specialist, has been involved in the green industry for more than two […]

Read More
Travis Higginbotham

February 8, 2016

Biocontrols And Next-Generation Production

Biocontrols are becoming much more established in greenhouse production. In some cases, it’s the next generation of growers that’s helping to support the adoption of this next generation of pest control. Travis Higginbotham, R&D Manager for Battlefield Farms, in Rapidan, VA, is a great example. Brought on in 2014, he is helping Battlefield take the next step in product development, as well as become more efficient as a business and adapt to new technologies and demands from their customers with a more proactive approach. Higginbotham will share information on Battlefield’s nematode program at the Biocontrols USA 2016 Conference and Expo, March 3-4, 2016 in Monterey, CA. We asked him about the details involved with building a new biocontrols program, as well as the future of sustainability in greenhouse production. Q: What are the differences in costs involved in using biocontrols? What costs should growers consider, aside from the hard costs […]

Read More
Jim Zablocki, Plant Prod

February 5, 2016

Sign Up For A Webinar On Using Plant Nutrition To Impro…

The webinar takes place March 2, and covers how leading growers are using plant nutrition to minimize costs, reduce the number of factors they need to worry about, and lessen environmental impacts.

Read More
Biocontrols Conference and Expo 2016

February 4, 2016

Biocontrols 2016 Conference Offers Insights And Learnin…

The Biocontrols 2016 Conference & Expo, which takes place March 3-4, 2016, in Monterey, CA, brings together growers, pest control advisers, suppliers, researchers, and other segments of the industry to share the latest information on biochemicals, microbial pesticides, and beneficials, and help you put biocontrols to work in your operation.

Read More
Fertilizer Rates Feature Image

January 29, 2016

Bioworks Releases New Higher Nitrogen Fertilizer For Or…

Verdanta N-Vita 9-4-3 promotes foliar growth and features a slow release process, making nutrients available for a longer period of time.

Read More
Primula acaulis, Botrytis, Disease, Griffin Greenhouse Supplies

January 19, 2016

EPA Approves Syngenta’s Mural Fungicide For Use On Seve…

Mural contains two active ingredients and is designed to provide broad-spectrum control of a wide range of root and foliar diseases.

Read More

January 12, 2016

EPA Releases Preliminary Risk Assessment For Imidaclopr…

The assessment, which will soon be open for public comment, indicates that imidacloprid potentially poses risk to hives when the pesticide comes in contact with certain crops that attract pollinators.

Read More
Sustane Research Greenhouse 2015

January 7, 2016

Fertilizer Manufacturers Aim To Deliver Sustainable Sol…

Industry experts discuss the latest trends to help ensure 2016 is your best year yet.

Read More
Vestaron

December 30, 2015

Vestaron’s Spear Bioinsecticide No Longer Carries Bee T…

Following a review that shows it has no detrimental effect on honeybees, EPA has removed the bee toxicity warning statement from Spear.

Read More
How To Overcome Downy Mildew Spread On Impatiens

December 16, 2015

Syngenta Launches Two New Fungicides For The Ornamental…

Solatenol and oxathiapiprolin, each with unique active ingredients, should be available to growers in early 2016.

Read More
Biocontrols Conference and Expo 2016

December 15, 2015

Mark Your Calendars For The Second Annual Biocontrols U…

Produced by Meister Media Worldwide in cooperation with the Biopesticide Industry Alliance, the event brings together growers, pest control advisors, researchers, biocontrols suppliers, and everyone who plays a role in this crucial element of integrated pest management programs.

Read More
Gerbera Yellow Sticky Card

December 10, 2015

Michigan State Offers Free Download Of Bulletin Coverin…

The new fact sheet provides photos and lists commercially available beneficial insects, their target insects, and key facts about biocontrol agents.

Read More
Landmark Open-Bottom Tray

December 8, 2015

Landmark Plastic Addresses Retailer Capillary Mat Requi…

With the availability of water being the number one global risk based on its overall impact to society, it’s no surprise that big name retailers like Walmart, The Home Depot and Lowe’s have taken aggressive steps to reduce their water consumption at store level. More specifically, for the Spring 2016 selling season, Walmart has mandated that its horticultural partners be capillary mat compliant. This means that plants typically watered top-down will now be required to be watered through a sophisticated watering mat that helps saturate the plants from the bottom up. To help growers embrace this new requirement, Landmark Plastic has developed a new trade gallon tray with an open bottom that enables plants to be watered from the roots up. This not only helps utilize water more efficiently, but also helps retailers reduce labor costs associated with the task of watering. “We’ve made it our business to solve problems […]

Read More
Arthij van der Veer Feature image

December 7, 2015

Sustainability Is Key To Your Operation’s Future

During Greenhouse Grower's 2015 Top 100 Growers Breakfast at Cultivate'15, Arthij ven der Veer of MPS (More Profitable Sustainability) discussed crop protection trends in Europe, Latin America, and around the world, and what to expect on the horizon.

Read More
Bee Vectoring Technology Bumblebee

December 1, 2015

New Crop Protection Solution Uses Bees To Deliver Bioco…

The new system from Bee Vectoring Technology incorporated a powdered crop protection material into the lid of commercial bumblebee hives. Bees pick up the product when they leave the hive and deposit it on every plant they visit.

Read More
Stockosorb Crystals_with water Agriculture leaf (Evonick)

November 21, 2015

9 Sustainable Growing Media Products For Superior Green…

Manufacturers are delivering new growing media products to help growers attempt to minimize their footprint without sacrificing quality. Here are nine new products to consider for your greenhouse operation.

Read More
Suzanne Wainwright-Evans

November 16, 2015

Real-World Biocontrols Trends From The Buglady

During ,em>Greenhouse Grower's Top 100 Breakfast at Cultivate'15, Suzanne Wainwright-Evans of Buglady Consulting discussed trends in biocontrols, including what she has seen from breeders, growers and even public gardens.

Read More

October 13, 2015

Bayer CropScience And OHP To End Marketing Partnership …

The move allows Bayer to market its ornamental products directly to greenhouses and nurseries, although OHP will still service a limited line of Bayer products.

Read More
[gravityform id="35" title="false" description="false"]