Wood chips and applications of wood chips in stormwater

This site is currently undergoing revision. For more information, open this link.
This page is in development

This page provides information on wood chips. While providing extensive information on wood chips, there is a section focused specifically on stormwater applications for wood chips.

Overview and description

Wood chips are small- to medium-sized pieces of wood formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste. They include bark, wood, and often leaves. Wood chips are rich in lignin, suberin, tannins. Common mulch sources include cedar, cypress, straw/hay, pine, and spruce. Organic wood mulch is often a byproduct of the lumber industry (typically shredded bark), wood recycling centers (i.e. pallets) or processed yard waste from public landfills.

In stormwater applications, wood chips are used as a mulch to provide one or more beneficial functions. Potential benefits of wood chips include but are not limited to the following. They

• decompose slowly;
• slowly release nutrients;
• effectively retain and slowly release moisture;
• moderate temperature;
• provide weed control;
• are sustainabile;
• are typically rewlatively cheap to purchase;
• resist compaction;
• create a diverse environment for soil biota; and
• may sequester some pollutants. such as nitrogen.

Physical and chemical properties of wood chips vary depending on the source, method of production, and age. Because of this variability, this page focuses on generic properties of wood chips used as mulch, except where otherwise stated.

Source

As discussed below, the properties of mulch vary with several factors, including the tree species, source of chips (e.g. bark, wood), and initial condition of the chips (e.g. age, moisture content, chip size). Aged wood mulch, which is preferred, is commonly available as bark nuggets, and as both shredded softwood (such as cedar or fir) and hardwood. Wood mulch feedstock may be dictated by region as softwoods are more prevalent on the west coast of the U.S. and hardwoods on the east coast. A double shredded bark 3-inch mulch layer is generally used in biofiltration practices. Triple shredded bark mulch may contain too many fines and single shredded may contain larger mulch more prone to floating. Bark nuggets should also be avoided to prevent floating as they are less dense. When softwoods are used, texture should be evaluated as some softwoods can be somewhat “mouse-nest” in appearance and contribute to floating (Hills, 2019).

Fresh wood mulch should be avoided. Composted mulch is typically free of disease, insects and weed seeds. Fresh wood mulch can remove nitrogen from the soil, which may be beneficial to nitrogen removal from stormwater, but can strip nitrogen away from landscape plants. Fresh wood mulch is typically available as wood chips and can be more prone to floating, exposing the media surface to erosion and obstructing overflows.

Shredded wood should be avoided. Shredded wood mulch tends to clog soil and form a mat which can restrict infiltration.

Properties of wood chips

This section includes a discussion of chemical and physical properties of wood chips, and potential contaminants in wood chips.

Chemical-physical properties of wood chips

Physical and chemical properties of wood chips varies by the source (e.g. species, wood or bark) and the physical dimensions of the wood chips. Chips from wood typically are 70-80 percent cellulose and 20-30 percent lignin, while chips from bark are roughly 50 percent cellulose and 50 percent lignin (Pintor-Ibarra et al., 2017). Other components comprise less than 5 percent of the total dry weight mass of wood chips.

The adjacent table summarizes select physical and chemical properties of wood chips. The table does not differentiate between species or whether the chips are from bark or wood residue. Some general observations regarding these include the following.

• Bark residues show a high content of inorganic compounds compared to wood residues
• Bark residues are more acidic than wood residues
• The major inorganic compounds found in ash are calcium, magnesium, and potassium.
• Heavy metal concentrations are low
• Extractives levels in barks are higher than in woods
• Nitrogen concentrations are lower and C:N ratios are higher in coniferous species compared to deciduous species
• In general, physical properties are more favorable as chip size decreases (e.g. from 12 mm diameter to 4 mm diameter). For example, CEC and water holding capacity increase as chip size decreases.

Chemical and physical properties of wood chips. For concentrations of metals, link here.
Link to this table

Property	Range found in literature1	Median value from literature
Total phosphorus (mg/kg)	0.027 - 0.24	0.13
Total nitrogen (mg/kg)	0.31 – 1.8	0.38
Total potassium (mg/kg)	100-1600	709
Total carbon (mg/kg)	434-498	47.1
pH	3.34-5.07	3.47
Cation exchange capacity (cmol/kg)1	bark: 57-92 wood: 30-46
Total calcium (mg/kg)	600-6200	1190
Total magnesium (%)	60-6200	189
Bulk density (g/cm3)	0.138 - 0.422	0.293
Water holding capacity (% by wt)		58.5
Total pore space (%)	60-63	61.5

Primary references for this data:

• Ima and Mann, 2007
• Hamid et al., 2016
• Pintor-Ibarra et al., 2016
• Kim et al., 2016
• Chandrasekaran et al., 2012
• Venner et al., 2011
• New York State Energy Research and Development Authority, 2013
• Warner, 1976
  

¹CEC increased as chip size decreased

Potential contaminants in wood chips

The adjacent table summarizes concentrations of heavy metals, selenium, and arsenic in wood chips in comparison with soil reference values (SRVs) and soil leaching values (SLVs). Concentrations in wood chips were typically well below risk criteria, with the only exception being maximum observed arsenic concentration, which exceeded the residential SRV. Additional data was found in the literature but is not included in the table. Other data in the literature show similar results.

Heavy metal concentrations (mg/kg) in wood chips (New York State Energy Research and Development Authority, 2013).
Link to this table

Metal	Mean1	Median1	SRV – residential2	SRV – commercial	SLV3
Vanadium	0.02	0.57	1.08	16	8
Chromium (III)	0.24	7.36	23160	100000	>100000
Manganese	70.6	272	2104	26000	260.4
Iron	18.1	345	10808	100000	na
Cobalt	0.03	0.14	4.62	69	54.1
Nickel	0.36	1.98	170	2600	352
Copper	1.32	3.41	2192	33000	1404
Zinc	5.93	17	4632	70000	6008
Arsenic	0.05	1.17	0.08	1.2	11.64
Cadmium	0.005	0.079	1.59	23	17.62
Lead	0.25	1.12	300	700	5401
Antimony	0.005	0.397	93	6.2	1.82
Barium	17.4	45.9	41000	3000	3368
Selenium	0.04	0.09	1200	77	5.28

¹ 13 samples
²SRV=Soil Reference Value (mg/kg)
³SLV=Soil Leaching Value (mg/kg); assumes 3 foot thick media and 3 foot separation from groundwater

Leachate from fresh wood chips is acidic, produces chemical oxygen demand, and releases nutrients. Negative aquatic response to leachate has been observed near wood chipping facilities and may be due to COD, phenols, organic compounds, or resin acids such as isopimaric acid (IA) and dehydroabietic acid (DHAA) (Machrafi et al., 2007; Taylor and Carmichael, 2003; Rex et al., 2016). Toxic effects associated with high oxygen demand from wood stockpiles have been observed in nearby receiving waters (Tao et al., 2005; Kannepalli et al., 2016). Studies indicate leaching of nutrients and organic compounds that contribute to oxygen demand decrease with time (Machrafi et al., 2007).

Wood chips from recycled wood may contain creosote and CCA (chromated copper arsenate). Wood chips from recycled wood is often colored with dyes. Dyes are typically organic- or iron-based and have not been found to be toxic. However, if colored wood chips are used, the wood source should be determined University of Massachusetts, Amherst.

Most studies indicate that diseased mulch cannot transmit pathogens to the roots of healthy trees. Mulch should not be incorporated into soil, under which conditions pathogens may be transmitted to trees ([1]; [2]).

Effects of wood chips on physical and chemical properties of soil and bioretention media

In this section we provide information on effects of wood chips on pollutant attenuation and on physical properties of soil and engineered media.

Effects of wood chips on retention and fate of phosphorus

No specific studies of phosphorus retention by wood chips in bioretention systems were found, though there are studies focused on nitrogen removal that also evaluated phosphorus. Christianson et al. (2017) studied a dual system consisting of a wood chip-based denitrification bioreactor coupled with either a steel slag or acid mine treatment residual system to remove phosphorus. The bioreactor did not remove phosphorus. Kuter et al (2017) observed that amending soil receiving biosolids with wood chips resulted in no phosphorus retention. Husk et al. (2018) found wood chip bioreactors vary in their effect on phosphorus leaching, with periods where phosphorus was retained and periods when phosphorus was released. Healy et al. (2012, 2015) and Sharrer et al. (2016) found initial leaching of phosphorus from wood chip bioreactors. Parvage et al. (2017) observed phosphorus retention by wood chips in manure-rich paddock soils. Since studies of nitrogen and phosphorus retention generally utilize dual systems, with one designed for nitrogen removal and the other for phosphorus removal, phosphorus retention by wood chips can be considered to be negligible. Similarly, several studies indicate wood chips are not an important source of phosphorus for vegetation, wood chips would not be expected to leach phosphorus in appreciable amounts.

Effects of wood chips on retention and fate of other pollutants

Several studies indicate wood chip bioreactors effectively reduce nitrogen concentrations through denitrification. These studies include specific design considerations for wood chip bioreactors. Many of these studies also indicate effective removal of dissolved organic carbon (Chang et al., 2018; Christianson et al., 2017; Ergas et al., 2010; Lopez-Ponnada et al., 2020; Wan et al., 2018; Kim et al., 2003; Peterson et al., 2015).

Chang et al. (2018) showed copper retention by wood chips.

Hills (2019) conducted a review of wood chips and reported research supports greater metals adsorption capacity for hardwood mulch due to its intrinsic properties including humic compounds consisting of carboxyl and hydroxyl functional groups, and greater cation exchange capacity, surface area and pH. Wood mulch is also known to capture oil and grease among other organic compounds. Wood mulch is also a host for microbial and macro-organism activity which supports plant health and pollutant degradation. Wood mulch sustains organic-based removal mechanisms as the mulch is decomposed and replenishes organic material within the media, also preserving water-holding capacity.

Hopkins et al. (2021) provide a literature review and summary of the effects of wood chips on pollutant retention. Below are direct excerpts from this paper, including references, which can be found in the References section on this page.

• Woodchips act as the carbon source in the biological degradation of nitrate, sulphate, ammonia, ammonium, and nitrite [5,13]. Particulate phosphorus is phosphorus adsorbed to suspended sediment, so it is removed by physical filtration along with suspended solids [2]. Orthophosphorus, is removed through sorption, and nitrates can be removed by sorption as well as biological degradation [14].
• Woodchips have proven effective for heavy metal removal, but some metals, such as arsenic, have not been studied [4,13,18-21]. Metals are removed through sorption to the woodchips and cation exchange with phenolic hydroxyl groups. The composition of the wood can greatly affect the removal efficiency of the metals [4].
• Several studies have found woodchips to effectively remove pesticides [15,21,22,24,25].
• Total petroleum hydrocarbons have shown to be effectively removed by wood products in many studies, by sorption to the woodchips as well as physical filtration of sediments to which hydrocarbons are sorbed and biological degradation [19,24,26-29].
• Halocarbons have been found to be removed by wood through sorption [28], [27], [19], [30], [24].
• There is a limited amount of research evaluating the ability of wood to remove water-borne pathogens. Pathogens are removed by sorption to woodchips or physical filtration if they are adsorbed to sediments in the inflow, causing the deactivation of pathogens by natural decay, desiccation, or predation [3].

• runoff from wood facilities
• [3]

• swale/ditch with wood chips
• denitrification

Effects of wood chips on soil physical and hydraulic properties

Wood chips increases the water holding capacity and water retention of soil and bioretention media, though these increases are less than compost and other mulches that have greater surface area (Davis and Whiting, 2013; van Donk et al., 2011; Perry). Shaw et al. (2005) observed an increase in water holding capacity of 0.81 in/ft in a soil in San Diego, California. Salzmon et al. (1958) observed water holding capacities of 99-138 percent of dry weight for wood chips from four species (red and jack pine, aspen, birch), with the lowest adsorption being for birch.

Wood chips reduce soil temperatures by retaining soil water and blocking direct solar radiation, and reduce diurnal temperature fluctuations. Temperature effects are typically limited to the upper 10 cm of the soil or media (Abdul Bari Awan, 1964; Kotze, 2012; van Donk et al., 2011, Perry).

Research shows mixed results for effects of wood chips on soil bulk density. Wood chips appear to have beneficial effects on reducing soil compaction, particularly when incorporated, but minimal impact in uncompacted soils (Choi et al., 2005; Venner et al., 2011; Tahboub et al, 2008; Qu et al., 2019; Scharenbroch and Watson, 2014; Antieau, 2017).

Standards, classification, testing, and distributors

Wood chip standards and specifications

Recommended values for wood chips used in a growth media (Source: see reference list in this section)
pH
Electrical conductivity (ms/cm)
Cation exchange capacity (meq/100g)
Nitrogen (%)
Phosphorus (%)
Potassium (%)
Copper (% minimum)
C:N ratio (minimum)
Lignin (%)
Total organic matter (% minimum)
Moisture (%)
Ash content (%)
Impurities
Fiber content
Expansion	l/kg
Water holding capacity	l/kg

Specifications exist for wood chips and pellets used for energy. Specific standards do not exist for wood chips used for other practices, but the Forest Stewardship Council (FSC) certifies wood sources, which guarantees that the wood and bark is responsibly sourced. The FSC Controlled Wood Standard (FSC-STD-040-005 Version 3.0) requires knowledge of where the wood comes from, an evaluation of the risk that a wood source is in violation with unacceptable categories of wood, and mitigate actions to reduce any risk from the wood source.

Products receiving Mulch & Soil Council Certification must pass rigorous screening and are periodically audited to ensure the products meet Council standards. The certification ensures the product label is accurate and all ingredients are listed, and product claims have been verified. A Mulch & Soil Certification also ensures the mulch contains no chromated copper arsenate.

Some general guidelines for material selection are provided below Hills, 2019.

• Recycled yard waste from public municipalities or recycled wood scraps such as pallets should be avoided due to inconsistencies in source and potential for unwanted trash or chemical additives in the mulch.
• Mulch should be free from waste wood material, harmful chemicals, or inorganic dyes.
• Mulch should not contain any fertilizer, pesticide, or other amendment.
• If mulch is being used in a nutrient sensitive area, a leachate analysis would ensure the mulch does not contribute to nutrient leachate from the practice.
• Mulches that include grass clippings, pine needles, straw, sawdust, leaf litter, turf, coir and compost should be avoided for biofiltration applications, particularly high flow media, to prevent hydraulic restriction, flotation, maintenance burdens and nutrient leaching.
• Composted or aged wood mulch, which is mulch that has had time to decompose, is a better option over fresh wood mulch for use in most landscape practices, including biofiltration. Composted mulch is typically free of disease, insects and weed seeds. Fresh wood mulch can be more prone to floating, exposing the media surface to erosion and obstructing overflows.
• Mulch sizes should be less than 1 inch, but excessive fines or sediment should be avoided as this can reduce infiltration rates. Additives such as compost should be avoided as a surface layer for biofiltration practices.

Distributors

• [4]
  • Availability and supply method are also important factors to consider. Sometimes it is more economical to purchase bulk mulch over bagged mulch depending on the size of the biofiltration practice, but bagged mulch can be easier to handle. If you are qualifying mulch you should make sure what you are testing is available year-round so that when it is time for mulch installation you can ensure the qualified product is available. Mulch is a natural product that can change over time, so periodic supplier quality checks are important.

Effects of aging

Prabhu and Thomas (2002) provide an extensive discussion of wood chips decomposition.

Storage, handling, and field application

Keep wood mulch away from the trunks of trees to prevent rot. If you are concerned about termites, use cedar mulch or keep other wood mulches at least 6 inches (15 cm.) from the foundation. Let your mulch age if you aren’t sure of your source. This allows time for any sprays that were used on the tree or diseases it may have had to break down.[5]

Read more at Gardening Know How: Types Of Bark Mulch: Tips For Using Wood Mulch In Gardens https://www.gardeningknowhow.com/garden-how-to/mulch/bark-mulch-in-gardens.htm

• Wetting wood mulch at installation and ensuring it receives irrigation will reduce the chance of mulch floating from the practice. The wetting and drying process allows caking or matting to occur. Inlet areas, or other areas receiving concentrated flow, should be designed with dissipator stones or other type of erosion control. Denser plant covers can also reduce mulch flotation. Mulch with higher moisture content and therefore greater density can also minimize floatability. Bark nuggets and wood chips should be avoided due to their lighter density and texture that lends itself to increased floatability.
• details

Sustainability

Using locally produced wood chips is a sustainable activity and keeps a useful product out of landfills.

Miscellaneous

• [6]
  • Use arborist wood chips. They absorb water and sink; bark repels water and floats and is more likely to clog inflows or overflows
  • Wood chips provide more nutrition than bark, which is essentially sterile
  • Wood chips discourage weed germination by tying up nitrogen at the soil surface; compost provides more nutrition for weeds to get growing

References

• Abdul Bari Awan. 1964. Influence of mulch on soil moisture, soil temperature and yield of potatoes. American Potato Journal volume 41, 337–339.
• Antieau, C. 2017. Wood Chips as a Soil Amendment. City of Seattle Pesticide Recertification Seminar. October 24, 2017.
• Ashoori N, Teixido M, Spahr S, Lefevre GH, Sedlak DL, et al. 2019. Evaluation of pilot-scale biochar-amended woodchip bioreactors to remove nitrate, metals, and trace organic contaminants from urban stormwater runoff. Water Research 154: 1-11.
• Bailey SE, Olin TJ, Bricka RM, Adrian DD. 1999. A review of potentially low-cost sorbents for heavy metals. Water Research 33(11): 2469-2479.
• Boving TB, Zhang W. 2004. Removal of aqueous-phase polynuclear aromatic hydrocarbons using aspen wood fibers. Chemosphere 54(7):831-839.
• Bras IP, Santos L, Alves A. 1999. Organochlorine pesticides removal by pinus bark sorption. Environmental Science & Technology 33(4):631-634.
• Broschat, Timothy K. 2007. Effects of Mulch Type and Fertilizer Placement on Weed Growth and Soil pH and Nutrient Content. Hort Technology 17(2):174-177. DOI:10.21273/HORTTECH.17.2.174.
• Chalker-Scott, Linda. 2007. Wood chip mulch:Landscape boon or bane?. Accessed May 25, 2021.
• Camilo BK, Matzinger A, Litz N, Tedesco LP, Wessolek G. 2013. Concurrent nitrate and atrazine retention in bioreactors of straw and

bark mulch at short hydraulic residence times. Ecological Engineering 55: 101-113

• Chandrasekaran, Sriraam R., Philip K. Hopke, Lisa Rector, George Allen, and Lin Lin. 2012. Chemical Composition of Wood Chips and Wood Pellets. Energy Fuels. 26:8:4932–4937. https://doi.org/10.1021/ef300884k.
• Chang, Ni-Bin, Martin P. Wanielista, and Dan Wen. 2018. Comparative Nitrogen and Pesticide Removal with Sorption Media in Linear Ditch for Groundwater and Stormwater Treatment. Stormwater Management Academy, University of Central Florida . Agency Number: BDV24-977-14.
• Choi, Hyun-Sug, Curt Rom, Jason D. McAfee. 2005. Effects of different organic mulch on soil physical characteristics and leaf nutrition in apple orchards. HortScience: a publication of the American Society for Horticultural Science 40(4). DOI:10.21273/HORTSCI.40.4.1027D
• Choudhury T, Robertson WD, Finnigan DS. 2016. Suspended Sediment and Phosphorus Removal in a Woodchip Filter System Treating Agricultural Wash Water. Journal of Environmental Quality 45(3): 796-802.
• Christianson, L., C. Lepine, P. Sibrell, and C. Penn. 2017. Denitrifying woodchip bioreactor and phosphorus filter pairing to minimize pollution swapping. Water Research, 121.
• Davis, J.G., and C.R. Wilson. 2013. Choosing a Soil Amendment Choosing a Soil Amendment. Colorado State University. Fact Sheet No. 7.235.
• Drake, Kevin, and Michael Hogan. 2015. Forest Management Guidebook An Outcome-Based Approach to Water Quality Protection. Integrated Environmental Restoration Services, Inc. Publication. 149 p.
• Edwards JD, Barton CD, Karathanasis AD. 2009. A Small-Scale Sulfate-Reducing Bioreactor for Manganese Removal from a Synthetic Mine Drainage. Water Air and Soil Pollution 203(1-4): 267-275.
• Ergas, Sarina J., Sukalyan Sengupta, Ryan Siegel, Arka Pandit. 2010. Performance of Nitrogen Removing Bioretention Systems for Control of Agricultural Runoff. Journal of Environmental Engineering 136(10). DOI:10.1061/(ASCE)EE.1943-7870.0000243.
• Hamid, Rezaei , Lim, C. Jim, Lau, Anthony, Sokhansanj, Shahab. 2016. Size, shape and flow characterization of ground wood chip and ground wood pellet particles. Powder Technology. Journal Volume: 301; Journal Issue: C; Journal ID: ISSN 0032-5910. https://doi.org/10.1016/j.powtec.2016.07.016.
• Healy, M.G., M. Barrett, G. Lanigan, A.J. Serrenho, T. Ibrahim, S. Thornton, S.A. Rolfe, W.E. Huang, and O. Fenton. 2015. Optimizing nitrate removal and evaluating pollution swapping trade-offs from laboratory denitrification bioreactors. Ecological Engineering 74:290-301.
• Healy, M.G., T.G. Ibrahim, G.J. Lanigan, A.J. Serrenho, and O. Fenton. 2012. Nitrate removal rate, efficiency and pollution swapping potential of different organic carbon media in laboratory denitrification bioreactors. Ecological Engineering 40:198-209.
• Hills, Mindy. 2019. Selecting the Right Mulch for your Biofiltration Practice. Contech website accessed May 25, 2021.
• Hopkins, Michelle A M, Adella M Kuster, Jason R Vogel1, and Glenn O Brown. 2021. Pollutant Removal in Stormwater by Woodchips. International Journal of Environmental Sciences and Natural Resources. Volume 26 Issue 5. DOI: 10.19080/IJESNR.2021.26.556200.
• Huang XJ, Massoudieh A, Young TM. 2006. Measured and predicted herbicide removal by mulch. Journal of Environmental EngineeringAsce 132(8): 918-925.
• Husk, B.R., J.S. Sanchez, B.C. Anderson, J.K. Whalen, and B.C. Wootton. 2018. Removal of phosphorus from agricultural subsurface drainage water with woodchip and mixed-media bioreactors. Journal of Soil and Water Conservation. May/June: Vol. 73, No. 3. doi:10.2489/jswc.73.3.265.
• Ima, C., and D. Mann. 2007. Physical Properties of Woodchip: Compost Mixtures used as Biofilter Media. International Commission of Agricultural Engineering. Volume 9.
• Johnson, Will Wheeler, Mara Braddy, and Bruce Bugbee 2017. Effect of Wood Chips and Rice Hulls on Water Holding Capacity of A Peat--‐based Substrate. Jakob Crop Physiology Laboratory, Utah State University. April--‐May.
• Jang A, Seo Y, Bishop PL. .2005. The removal of heavy metals in urban runoff by sorption on mulch. Environmental Pollution 133(1): 117-127.
• Kannepalli, Sarat, Peter F Strom, Uta Krogmann, Vandana Subroy, Daniel Giménez, and Robert Miskewitz. 2016. Characterization of wood mulch and leachate/runoff from three wood recycling facilities. J Environ Manage. 182:421-428. doi: 10.1016/j.jenvman.2016.07.093.
• Kim, Hunho, Eric Seagren, and Allan P. Davis. 2003. Engineered Bioretention for Removal of Nitrate from Stormwater Runoff. Water Environment Research 75(4):355-67. DOI:10.2175/106143003X141169.
• Kim, Ji-Su, Ji Young Jung, Si Young Ha, Jae-Kyung Yang . 2016. Physicochemical Properties and Growth Characteristics of Wood Chip and Peat Moss Based Vegetation Media. J. Korean Wood Sci. Technol. 44(3): 323-336.
• Kotze, Willem Petrus. 2012. The Effect Of Mulching On Tree Performance And Fruit Quality Of ‘Cripps’ Pink’ Apples. M.S. Thesis. Stellenbosch University.
• Kuter, Geoffrey, Mike Carignan, and Dave Harding. 2017. Phosphorus in Compost and Risks to Water Quality. Managing Residuals In A Complex World. The Northeast Residuals & Biosolids Conference. Burlington VT.
• Lopez-Ponnada, Emma V., Thomas J. Lynn, Sarina J. Ergas, and James R. Mihelcic. 2020. Long-Term Field Performance of a Conventional and Modified Bioretention System for Removing Dissolved Nitrogen Species in Stormwater Runoff. Water Research. Volume 170, 115336. https://doi.org/10.1016/j.watres.2019.115336
• Lynn, Thomas J.; Yeh, Daniel H.; Ergas, Sarina J. 2015. Performance and Longevity of Denitrifying Wood-Chip Biofilters for Stormwater Treatment: A Microcosm Study. Environmental Engineering Science . Vol. 32 Issue 4, p321-330. 10p.
• Machrafi, Younes, Danielle Prévost, Chantal J Beauchamp. 2007. Toxicity of Phenolic Compounds Extracted from Bark Residues of Different Ages. Journal of Chemical Ecology 32(12):2595-615. DOI:10.1007/s10886-006-9157-1.
• Mackay AA, Gschwend PM. 2000 Sorption of monoaromatic hydrocarbons to wood. Environmental Science & Technology 34(5):839-845.
• Melone MA. 2016. Bio-separator Design Improvements for Removal of Petroleum Hydrocarbons from Runoff (Master’s thesis, Oklahoma State University, Stillwater, Oklahoma, USA).
• Mitchell, David K. 2014. Urban Landscape Management Practices as Tools for Stormwater Mitigation by Trees and Soils. M.S. Thesis. Virginia Polytechnic Institute and State.
• New York State Energy Research and Development Authority. 2013. Elemental Analysis of Wood Fuels – Final Report. NYSERDA Report 13-13 NYSERDA Contract 11165 June 2013.
• Parvage, Mohammed Masud, Barbro Ulén, and Holger Kirchmann. 2017. Can Organic Materials Reduce Excess Nutrient Leaching from Manure-Rich Paddock Soils?. J Environ Qual. 46(1):105-112. doi: 10.2134/jeq2016.06.0223.
• Perry, Leonard. Wood Chips as Mulch. University of Vermont Extension. Accessed May 25, 2021.
• Pintor-Ibarra, Luis Fernando, Artemio Carrillo-Parra, Rafael Herrera-Bucio, Pablo López-Albarrán, José G. Rutiaga-Quiñones. 2017. Physical And Chemical Properties Of Timber By-Products From Pinus Leiophylla, P. Montezumae And P. Pseudostrobus For A Bioenergetics Use. Wood Research 62 (6):849-862.
• Qu, Bingpeng , Yuanxin Liu, Xiangyang Sun, Suyan Li, Xinyu Wang, Kaiyi Xiong, Binghui Yun, Hua Zhang. 2019. Effect of various mulches on soil physico— Chemical properties and tree growth (Sophora japonica) in urban tree pits. PLOS One. February. https://doi.org/10.1371/journal.pone.0210777.
• Peterson, I.J., Sara Igielski, and Allen P. Davis. 2015. Enhanced Denitrification in Bioretention Using Woodchips as an Organic Carbon Source. Journal of Sustainable Water in the Built Environment, Vol. 1, Issue 4. https://doi.org/10.1061/JSWBAY.0000800
• Ray AB, Selvakumar A, Tafuri AN. 2006. Removal of selected pollutants from aqueous media by hardwood mulch. Journal of Hazardous Materials 136(2): 213-218.
• Rex, John F., Stephane Dube, Phillip Krauskopf, Shannon Berch. 2016. Investigating Potential Toxicity of Leachate from Wood Chip Piles Generated by Roadside Biomass Operations. Forests 7(2):40. DOI:10.3390/f7020040
• Salzman, J.A., E. T. Sullivan, J. R. Neetze1, and C. J. Shiue. 1958. The Water Holding Capacity of wood chips as Compared with Common Livestock Beddings. Minnesots Forestry Notes No. 69.
• Scharenbroch, Bryant C. and Gary W. Watson. 2014. Wood Chips and Compost Improve Soil Quality and Increase Growth of Acer rubrum and Betula nigra in Compacted Urban Soil. Arboriculture & Urban Forestry. 40(6): 319–331.
• Seelsaen N, McLaughlan R, Moore S, Stuetz RM. 2006. Pollutant removal efficiency of alternative filtration media in stormwater treatment. Water Science and Technology 54(6-7): 299-305.
• Seo Y, Lee WH, Sorial G, Bishop PL (2009) The application of a mulch biofilm barrier for surfactant enhanced polycyclic aromatic hydrocarbon bioremediation. Environmental Pollution 157(1): 95-101.
• Sharrer, K.L., L.E. Christianson, C. Lepine, and S.T. Summerfelt. 2016. Modeling and mitigation of denitrification ‘woodchip’ bioreactor phosphorus releases during treatment of aquaculture wastewater. Ecological Engineering 93:135-143.
• Shaw, David A., Dennis R. Pittenger, Mark McMaster. 2005. Water Retention and Evaporative Properties of Landscape Mulches. 2005. Proc. 26th Annl. Irrigation Show, Phoenix, AZ, Nov. 6-8, 2005. Irrigation Assoc., Falls Church, VA.
• Shenl H, Adair C, Wilson JT. 2010. Long-Term Capacity of Plant Mulch to Remediate Trichloroethylene in Groundwater. Journal of Environmental Engineering-Asce 136(10): 1054-1062.
• Soupir M, Hoover N, Moorman T, Law J, Bearson B. 2018. Impact of temperature and hydraulic retention time on pathogen and nutrient removal in woodchip bioreactors. Ecological Engineering 112: 153-157
• Tahboub, Mohammed B. , William C. Lindemann, Leigh Murray. 2008. Chemical and Physical Properties of Soil Amended with Pecan Wood Chips. HORT SCIENCE 43(3):891–896.
• Taylor, Barry R. , N. Bruce Carmichael. 2003. Toxicity and Chemistry of Aspen Wood Leachate to Aquatic Life: Field Study. Environmental Toxicology and Chemistry 22(9):2048-56. DOI:10.1897/02-183.
• Trapp S, Miglioranza KSB, Mosbaek H. 2001. Sorption of lipophilic organic compounds to wood and implications for their environmental fate. Environmental Science & Technology 35(8): 1561-1566.
• van Donk, Simon J., Dale T. Lindgren, Daniel M. Schaaf, James L. Petersen, and David D. Tarkalson. 2011. Wood chip mulch thickness effects on soil water, soil temperature, weed growth and landscape plant growth. Journal of Applied Horticulture, 13(2): 91-95.
• Venner, K. H., Preston, C. M. and Prescott, C. E. 2011. Characteristics of wood wastes in British Columbia and their potential suitability as soil amendments and seedling growth media. Can. J. Soil Sci. 91: 95_106.
• Tao, Wendong, Ken J. Hall, Arash Masbough. 2005. Characterization of Leachate from a Woodwaste Pile. Water Qual. Res. J. Canada. Volume 40, No. 4, 476–483.
• Wan, Zhexi, Tian Li, and Yutong Liu. 2018. Effective nitrogen removal during different periods of a field-scale bioretention system. Environmental Science and Pollution Research 25(3–4). DOI:10.1007/s11356-018-1954-x.
• Xuan ZM, Chang NB, Wanielista M, Hossain F. 2010. Laboratory-Scale Characterization of a Green Sorption Medium for On-Site Sewage Treatment and Disposal to Improve Nutrient Removal. Environmental Engineering Science 27(4): 301-312.