Control Unwanted Trees Using Hack-and-Squirt Herbicide Applications

June 25, 2019

UNIVERSITY PARK, Pa. -- Dense understories of undesirable shade-tolerant trees including red maple, American beech, blackgum, black birch, striped maple, and eastern hophornbeam interfere with the establishment and development of desirable regeneration such as oak, cherry, and poplar. Researchers have concluded that diversity declines as shade-tolerant tree species continue to expand. Recognizing and treating less-desirable trees increases the proportion of desirable species in future timber stands.

Removing or deadening undesirable trees is a forest man¬agement tool owners can employ to achieve their objectives. It allows the owner to favor species better suited to the site that meet desired conditions and objectives. The most effective method for deadening undesirable standing trees involves the use of herbicides.

Hack-and-squirt, also known as frill and spray, herbicide applications are one of the most target specific and economical means for controlling unwanted trees. Applications made to undesirable trees facilitates the regeneration or growth of desirable species. Hack-and-squirt applications are effective on various size stems and are applicable in hardwood stands where mechanical broadcast spray treatments are not feasible or desirable.

Hack-and-squirt applications introduce the herbicide into the stem using spaced cuts made at a convenient height around the trunk. Using a hatchet, downward-angled incisions are spaced evenly around the stem, one per inch of diameter (two cuts minimum).

Cuts are approximately 2 inches long and spaced 1 to 2 inches apart. The cuts must penetrate through the bark into the living tissue or sapwood and produce a cupping effect to hold

the herbicide. Each cut is filled with herbicide using a spray bottle.

Hack-and-squirt herbicide applications are effective at any time of the year, except during heavy spring sap flow. Applica¬tions made during periods of heavy sap flow are inef¬fective. In addition, do not treat when trees are solidly frozen. When hard freezes are forecasted to occur at night following application, add RV antifreeze (propylene glycol) to the spray solution according to label directions.

Applications to control root-suckering species such as beech, blackgum, and tree-of-heaven are most effective from July to the onset of fall coloration.

Hack-and-squirt applications are target-specific treatments generally used to control trees that are 1 inch in diameter and greater. They are most commonly used in hardwood forest timber stand improvement projects to deaden less desirable trees. These applications are often used to help establish desirable regeneration by removing low shade cast by dense understories of undesirable saplings and poles (trees 4-10 inches in diameter). Hack-and-squirt treatments control competition without impacting existing regeneration or desirable residual trees. Hack-and-squirt is also effective for releasing crop trees in hardwood stands. In addition, hack-and-squirt can be used to create standing dead trees, called snags, to provide desirable wildlife habitat.

Herbicides used for hack-and-squirt applications are water-soluble systemic materials, meaning they move vertically and horizontally within the tree. Numerous “general use” products have labels for hack-and-squirt applications, meaning forest landowners can purchase these products and apply them to their own properties without cer¬tification.

Traditional understory treatments have used mechanized (skidder-mounted) mist blowers. For a more selective application, consider hack-and-squirt treatments. They offer one of the saf¬est, most efficient, target-specific, and least expensive means of eliminating unwanted trees. The herbicides used are non-restricted and control a wide range of common spe¬cies. Hack-and-squirt provides a flexible tool landowners and managers can use to accomplish a variety of vegetation man¬agement objectives over a wide range of forest types.

For more detailed information view the new Forest Science Fact Sheet entitled Using Hack-and-Squirt Herbicide Applications to Control Unwanted Trees by visiting the Penn State Extension website at https://extension.psu.edu/using-hack-and-squirt-herbicide-applications-to-control-unwanted-trees or call 814-355-4897.

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EDITOR: For more information, contact Dave Jackson (814-355-4897, drj11@psu.edu).

PA Land Trust Association Honors Troy Firth

PALTA Honors Troy Firth with Lifetime Conservation Leadership Award

On May 17, the Pennsylvania Land Trust Association (PALTA) honored Troy Firth with the 2019 Lifetime Conservation Leadership Award. Firth received the award at the annual Pennsylvania Land Conservation Conference, held this year at Skytop Lodge.

For over 45 years, Troy Firth has set himself apart as a responsible and thoughtful pioneer in sustainable forestry.

Since 1971, Firth has practiced sustainable forestry as the owner and manager of Firth Maple Products, producing and selling certified organic maple syrup while taking a different approach to sustainable timber harvesting. Firth led the movement towards uneven-aged forest management instead of intensive even-aged management, a method that cultivates greater forest habitat diversity and ecosystem integrity. In an era when mechanical tree removal is the status quo, Firth uses horses to skid logs on his 7,000 acres of forest, demonstrating that horses can meet the needs of industrial forestry without compromising the health of the forest floor.

To read the full story click here.

Tree-of-Heaven Added to Controlled Plants and Noxious Weed List

A meeting of the Controlled Plant and Noxious Weed Committee was held on April 25, 2019, in Harrisburg at the Department of Environmental Protection, Southcentral Regional Office. The purpose of the meeting was to consider the addition of four plants to the noxious weed list and to consider a change of noxious weed class for one plant.

A quorum of the Committee was present at the meeting. After the acknowledgement of written public comments received and a discussion of the Committee, the Committee voted to approve tree-of-heaven (Ailanthus altissima) for addition to the noxious weed list as a class B Noxious Weed.

The addition of the previously listed plants to the Controlled Plants and Noxious Weeds list will become effective 60 days from publication of their notice, Saturday, June 1, 2019.

The PA Department of Agriculture defines Class B Noxious Weeds as follows: The department may require control of Class B weeds to contain an injurious infestation, or may provide education or technical consultation. In addition to tree-of-heaven, the following are Class B noxious weeds.

Bull thistle or Spear thistle - Cirsium vulgare

Canada Thistle - Cirsium arvense

Musk Thistle or Nodding Thistle - Carduus nutans

Johnson Grass - Sorghum halepense

Mile-a-Minute – Persicaria perfoliata

Multiflora Rose - Rosa multiflora

Purple Loosestrife - Lythrum salicaria

Shattercane - Sorghum bicolor

Poison hemlock – Conium maculatum

For more on the PA Department of Agriculture’s Noxious, Invasive and Poisonous Plant Program click here.