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...
Syngenta CAST 2015

July 27, 2015

New App Brings Syngenta Flowers’ Portfolio To Growers

Syngenta Flowers' newest app allows growers and brokers to quickly access information, descriptions, photos, culture and more on all of Syngenta's varieties.

Read More
Heating Feature image

July 27, 2015

In Hot Pursuit Of Heating Trends For The Greenhouse

From biomass boilers to hydronic-heating systems, growers have a range of options to fit their operation’s unique needs. Here’s what five manufacturers had to say about the latest trends.

Read More
Suzanne McKee

July 27, 2015

ePlantSource’s Suzanne McKee To Hike Grays Peak To Benefit Charlotte and Gwenyth Gray

Just a few years after welcoming their two daughters into the world, Gordon and Kristen Gray are faced with the agonizing diagnosis that their girls, Charlotte and Gwenyth Gray, both have Batten Disease CLN6, a rare neurodegenerative disorder that currently has no cure and is fatal. Children afflicted with this usually do not survive past the age of 12. Since the diagnosis, the friends and family of the Grays, including Suzanne McKee from ePlantSource, have come together to show an enormous amount of support through viral social media campaigns, silent auctions, lemonade stands and various other events and fundraisers. Celebrity support has also come in droves from celebrities such as Ali Larter, Channing and Jenna Dewan Tatum, Drew Barrymore, Dwayne Johnson, Eva Longoria and countless others. The Colorado friends of the Gray family are hiking Grays Peak on August 29 in support of Charlotte and Gwenyth. McKee and Brooke Michaels […]

Read More
Latest Stories
Feature image The Aphid Guard Aphid Banker Plant, coming soon to the market, supports beneficial insect populations.

June 21, 2015

The Latest In Crop Protection

Protecting your plants from the latest threats is no easy task, but new product lines promise to safely and effectively eliminate a wide range of pests and diseases, without harming your employees or the environment.

Read More
Bee On Flower

June 18, 2015

Pest Management And Marketing Strategies For Bee-Friend…

Michigan State University Extension shares pest management practices to produce plants that are safe for pollinators and marketing strategies for clearing up confusion about bee-friendly plants.

Read More
NSOrganicPlantFood3-1-1_featured

June 13, 2015

UMASS Fertilizer Trials Recommend Nature’s Source Organ…

In a recent online fact-sheet at its Extension website, the UMass Amherst Center for Agriculture, Food and the Environment lists Nature’s Source Organic Plant Food 3-1-1 as “the best liquid organic fertilizer,” according to Dr. Douglas Cox, Stockbridge School of Agriculture. It is called-out by the Extension after a number of years of studying the use of organic fertilizers for growing commercial greenhouse crops. The trials evaluated traditional water soluble and granular slow-release chemical fertilizers. Dr. Cox recommends Nature’s Source Organic Plant Food 3-1-1 as a liquid fertilizer that is readily available, cost effective, OMRI-listed and with good label directions for greenhouses. He also mentions the ease-of-use in how it mixes well with water and can pass fertilizer injectors. “Nature’s Source is currently the best liquid organic fertilizer,” Cox wrote in his article “Organic Fertilizers – Thoughts on Using Liquid Organic Fertilizers for Greenhouse Plants,” “I have seen no foliar chlorosis yet with this fertilizer. Nature’s source is widely available and a great […]

Read More

June 10, 2015

BASF’s Sultan Miticide Receives California Regist…

BASF Sultan miticide recently received registration in California, giving ornamental growers a new rapid, targeted mode of action for mite control. Sultan miticide, with active ingredient cyflumetofen, offers ornamental growers targeted knockdown of all life stages of tetranychid mites, with long residual control. It has practically no toxicity to beneficial insects, including predatory mites and pollinators. Sultan miticide offers a new mode of action to combat cross-resistance with other commercial miticides, and is compatible with integrated pest management programs (IPM). “The long-awaited California registration of Sultan miticide is exciting news. Greenhouse, nursery and landscape professionals in the state now have a new class of chemistry that gives them fast control over all life stages of plant-damaging mite populations,” says Joe Lara, senior product manager for BASF. “Sultan miticide now provides California growers with a much needed new first choice for miticide resistance management programs that won’t disrupt populations of beneficial […]

Read More
Bee on a Sedum

May 27, 2015

Industry Associations State Their Support Of National P…

AmericanHort, Society of American Florists, American Floral Endowment and Horticultural Research Institute joined together to embrace key aspects of the federal government’s recently announced National Strategy for the Protection of Honey Bees and Other Pollinators. The long-awaited strategy has three major goals: reducing honey bee colony losses, increasing Monarch butterfly populations, and restoring or enhancing millions of acres of land as pollinator habitat through public and private action. According to the statement, the associations are studying the details, but they agree that the overall approach appears balanced and mostly sensible. The rest of the statement reads as follows: “The national strategy’s overarching goals dovetail well with the focus of the ongoing Horticulture Industry Bee and Pollinator Stewardship Program. Under that initiative, we have directly funded several priority research projects, and collaborated on additional research funded by others, to provide critical scientifically sound guidance for professional horticulturists. We are developing a grower […]

Read More
Bee On Flower

May 20, 2015

White House Task Force Releases Pollinator Health Strat…

An interagency Pollinator Health Task Force commissioned by President Obama released its “Strategy to Promote the Health of Honey Bees and Other Pollinators” on May 19. The strategy, released in accordance with the Presidential Memorandum issued last June, is accompanied by a Pollinator Research Action Plan, which outlines needs and priority actions to better understand pollinator losses and improve pollinator health. The recommended actions will be supported by a coordination of existing federal research efforts and accompanied by a request to Congress for additional resources to respond to losses in pollinator populations. Pages 47 through 52 specifically address pesticides and pollinators. The report calls out plant production, native plants, mosquito control and all urban uses in its Pollinator Action Plan. RISE (Responsible Industry for a Sound Environment) says it supports the goals of improving pollinator health and habitat contained in the White House Pollinator Task Force’s release of its National […]

Read More
r3bv2 disease

May 20, 2015

SAF And AmericanHort Ask Government To Take Ralstonia O…

The Society of American Florists (SAF) and AmericanHort want Ralstonia solanacearum, Race 3, Biovar 2 (R3Bv2) taken off a list of animal and plant diseases that the federal government has determined could be misused as terrorist weapons. SAF and AmericanHort submitted formal comments together on the horticulture industry’s science-backed position on the matter. According to Lin Schmale, SAF’s senior director of government relations, extensive research has proven R3Bv2 does not belong on the government’s list of animal and plant diseases that can be misused as terrorist weapons. Every two years, USDA’s Animal and Plant Health Inspection Service (APHIS) requests a public review of the Select Agent list, asking for comments on whether plant or animal diseases should be taken off the current list or added to it. In the floral industry, R3Bv2 can have a devastating impact on geranium (pelargonium) crops, Schmale says, and both the potato and tomato industries also could be adversely affected by introduction […]

Read More
Two-spotted spider mites, adults and eggs

May 18, 2015

Beware Of Spider Mites In Bougainvillea And Mandevilla …

Greenhouse growers need to scout for spider mites on bougainvillea and mandevilla and use appropriate treatments that minimize pesticide resistance.

Read More
CrownBees_Blue-Orchard-Bee-Female_Artz

May 14, 2015

Pollinator Health 2015: What’s Next For Horticult…

The news on pollinators and neonicotinoids continues to fluctuate between good and bad. Research and outreach efforts backed by the Bee and Pollinator Stewardship Initiative help move the industry in a positive direction.

Read More
empress-intrinsic-brand-fungicide

May 13, 2015

BASF’s Empress Intrinsic Fungicide Is Approved Fo…

BASF’s Empress Intrinsic brand fungicide received supplemental labeling, providing California growers with an effective drench fungicide for disease control and plant health. The supplemental labeling is for use on herbaceous and woody plants in greenhouse, nursery container and field production in California. Empress Intrinsic fungicide provides protection against the four major root and crown disease pathogens: fusarium, phytophthora, pythium and rhizoctonia. Research shows Intrinsic fungicides control the broadest range of ornamental diseases while improving plant resilience to quality and reducing stresses that commonly occur during commercial production, handling and transportation. “More and more growers across the country are discovering the benefits of Empress Intrinisic brand fungicide treatments at propagation for rooted plugs, cuttings and seedlings, and in drench applications on transplants during the production cycle to protect against the major root diseases,“ says Joe Lara, senior product manager for BASF ornamentals. “A BASF fungicide program utilizing Pageant Intrinsic and Empress Intrinsic […]

Read More
Green Mum Basket

April 21, 2015

Growers Face Dilemma In Managing Plant Growth

Whether you’re applying plant growth regulators, manually pinching plants or using automated trimming, the most important thing is to find the right balance.

Read More

April 20, 2015

Three Michigan State University On-Demand Webinars Offe…

The first rule of effective insect and disease control for vegetables is to take action to prevent problems before they occur. But in order to do that, you need to have an effective pest and disease management strategy in place that incorporates best practices to ensure a successful outcome. Michigan State University offers three pest and disease management on-demand webinars that will get you started and keep you on the right track.

Read More

April 15, 2015

BASF’s Pageant Intrinsic Fungicide Registration A…

The state of California has approved the supplemental label registration of Pageant Intrinsic brand fungicide for disease control in the commercial production of greenhouse-grown tomatoes and tomato transplants for the home consumer market.

Read More
Egg card used for insect control in Parkway Garden’s retail area.

April 13, 2015

Biocontrols Use Requires Commitment

For some companies, a switch to biocontrols is an easy decision to make. Parkway Gardens of Ontario, Canada, began using biocontrols nine years ago after Erik Jacobsen, the company’s owner, wanted to expose Parkway, its customers and the environment to fewer pesticide products. “Many pesticides were increasingly ineffective, and in Canada, new product registration moves with glacial slowness,” Jacobsen says. “The labor cost of applying pesticides is much greater than using biocontrols.” In addition, it was also an opportunity to market the company’s eco-friendliness to a younger demographic, he says. In a Q & A with Greenhouse Grower, Jacobsen explains what biocontrols and methods have proved effective for Parkway Gardens Greenhouse Grower: In what types of greenhouse structures are you using biocontrols? Erik Jacobsen: Our greenhouses are all poly covered. About half the range is a Westbrook 14-foot at peak gutter-connected block, and the remaining half a mix of quonset-style […]

Read More

April 11, 2015

Lowe’s Announces Commitment To Phase Out Neonicotinoids…

Home improvement retailer Lowe’s companies announced April 9 that it has committed to eliminate neonicotinoid pesticides from its stores in a gradual phase-out over the next 48 months. In response, horticulture industry associations issued a statement that Lowe’s position is surprising, considering the most recent and positive reports on the state of honeybee health and recent peer reviewed research, and that this is an issue for which sound science must take priority.

Read More

April 9, 2015

Survey Snapshot Shows Biocontrols Mainstreaming

Have you incorporated biocontrols into your greenhouse operation? If so, you’ve got plenty of company. An anonymous online survey by Greenhouse Grower magazine in December 2014 of more than 156 ornamental plant and flower growers across the U.S. found 81 percent used biocontrols in 2014.

Read More

March 31, 2015

Manufacturers Are Taking Biologicals To The Next Level

Through acquisitions and new products, many crop protection companies are making firm commitments to the future of the biocontrols industry.

Read More
OxiPhos_BioSafe2

March 23, 2015

BioSafe Makes Label Changes To OxiPhos And ZeroTol 2.0

There have been some recent label changes made to the BioSafe Systems product OxiPhos, a systemic bactericide/fungicide that reduces downy mildew spores when tank mixed with ZeroTol 2.0.

Read More