Alternative 2: Removal of Infested Trees

Infested Trees

invertebrate species depend on understory vegetation (Oliver and Larson, 1996; Koide and Wu, 2003; Pineda et al., 2005). The removal of trees infested with ALB would reduce the canopy cover, creating an

environment favorable to shade-intolerant vegetation.

The process of removing trees can damage surrounding vegetation. Felled trees, vehicles, and other tree removal equipment can compress vegetation and soil. The introduction of weeds and invasive plant species on

equipment could alter the vegetative understory. In some instances, the Program applies an herbicide to stumps to prevent sprouting, although the preference is to grind the stumps in place. During recent ALB eradication efforts, greater than 75 percent of the stumps were removed rather than being treated with an herbicide. While herbicide application is directly on the stump surface, and according to label instructions, damage to nearby vegetation could occur from drift or runoff.

b. Environmental Resources (1) Water

The removal of infested trees near aquatic resources can impact water quality. In particular, the movement of soil into aquatic resources (rivers, lakes, and other bodies of water) can result in sedimentation, excessive nutrients (eutrophication), increased turbidity or cloudiness, and alteration of stream flow. In addition, tree removal adjacent to aquatic resources can reduce shading, which is important in maintaining water temperature. Degradation of water quality due to sedimentation can result in negative effects to aquatic organisms through direct or indirect impacts to fish, aquatic insects, and crustaceans, such as freshwater mussels and crayfish (Richter et al., 1997; Henley et al., 2000). The risk to soil quality and aquatic resources from erosion, due to tree removal, can be reduced by the implementation of timber BMPs (Aust and Blinn, 2004).

(2) Air

As described in the environmental consequences for the no action

alternative, the loss of trees to ALB infestation could affect air quality and contribute to climate change. The degree to which air quality and climate change are affected depends on the human-facilitated contribution of air pollutants, as well as the number of trees infested with ALB.

Trees infested with ALB reach mortality within 10 to 15 years. During the declining stage, trees continue to intercept air pollutants and sequester CO2; however, stress to these trees decreases their ability to sequester

reduces the interception of air pollutants and sequestration of carbon dioxide. Trees release stored carbon during decomposition or burning. Under this alternative, the Program removes and chips infested trees. Wood chips decompose at a faster rate than intact woody material, resulting in a faster release of carbon dioxide (McPherson and Simpson, 1999). Replacement of trees through succession or planting would restore air quality attributes to the area; however, this would occur slowly over time and would vary depending on the types of species that may regrow in areas.

The loss of trees through the removal of ALB-infested trees by the Program would temporarily affect the local carbon sequestration. For example, the potential total CO2 release estimate from trees and soil at five

ALB eradication sites active in 2012 is 20,187 mt (appendix D). These levels are below the CEQ reference level of 25,000 mt for all GHGs; other GHGs (methane, nitrous oxide, hydro-fluorocarbons, perfluorocarbons, and sulfur hexafluoride) were not included in this study. The restoration of vegetation and trees reduce the contribution of CO2 to the atmosphere

from the removal of trees by the Program.

In urban areas, where trees now shade buildings, tree removal under ALB eradication would increase energy requirements and emissions of GHGs from power plants to compensate for increased heating in winter and air conditioning in summer. For example, in New York City, trees are estimated to reduce energy costs from residential buildings by

$11.2 million annually based on 2002 energy costs. Trees also provide an additional $167,000 in value per year by reducing the amount of carbon released by the city’s fossil-fuel based power plants (a net reduction of 9,100 tons of carbon emissions) (Nowak et al., 2007).

Several U.S. cities have greening programs (e.g., Boston (http://www. growbostongreener.org/gbg/) and Baltimore

(http://www.baltimoretreetrust.org/) aimed at increasing tree cover to achieve benefits trees provide, including improved air quality,

sequestration of carbon, reduced energy consumption, and flooding control (Nowak et al., 2007; Nowak et al., 2010). The removal of infested trees prior to mortality in urban areas and adjacent forest would negatively affect these benefits. However, infested trees weaken over time and eventually fail to benefit the urban environment; rather, they may become a fall hazard. In addition, leaving infested trees leads to additional tree infestations due to ALB spreading resulting in more tree loss.

The combustion of gasoline and diesel fuel in machinery used to remove and chip trees release air pollutants and GHGs (McPherson and Simpson, 1999). Estimates of release for these activities are scarce, including data

from ALB Eradication Program activities. Emissions from tree removal and chipping activities would have the greatest impact to air quality in urban areas where air quality may already be impacted.

(3) Soil

Soil quality impacts under this alternative (Alternative 2: Removal of Infested Trees) would be similar or, in some cases, more significant than those described under the no action alternative. Under this alternative infested trees would be removed, which could result in physical and chemical impacts to soils, especially in areas where soils are vulnerable to erosion. The removal of only infested trees without addressing host trees nearby at risk of infestation could also allow ALB to continue to spread, resulting in additional tree removals in areas where soils may be

susceptible to erosion.

c. Ecological Resources

The removal of infested trees would have impacts to ecological resources similar to those described under the no action alternative, although at a potentially slower rate in the long term. Initially the rate of tree loss under this alternative would be greater in the infested areas compared to the no action alternative since trees would be removed more quickly than through natural loss from ALB. In cases where infested trees are removed, some of the impacts previously noted could occur. However, the expansion of ALB resulting from not removing high-risk host trees within the known dispersal range of ALB would leave those trees vulnerable, and

infestations would continue to occur, resulting in additional removal of infested trees.

Herbicide Use

APHIS uses herbicides when there are limitations to physical removal of stumps. The limitations include those areas that are inaccessible to equipment used for stump grinding, and those areas that are sensitive to erosion or compaction.

The Program uses the herbicide triclopyr by spraying or painting the root collar area (the sides of the stump) and the outer portion of the cut surface, including the cambium (thin layer of generative tissue lying between the bark and the wood of a stem), until thoroughly wet, but not to runoff. Foliar applications of triclopyr mixed with two other herbicides, imazapyr and metsulfuron-methyl, would be applied to sprouting foliage from stumps that remain after tree removal to prevent regrowth.

Triclopyr triethylamine salt (TEA) toxicity to terrestrial wildlife is considered low. Toxicity to avian species is low for triclopyr TEA with oral and dietary median lethal toxicity values greater than the highest test concentrations tested (EPA, 1998; Durkin, 2003). Chronic toxicity to birds is also expected to be low with reproductive toxicity. The no observable effect levels (NOEL) are 100 and 500 parts per million (ppm) for the mallard and bobwhite quail, respectively, when exposed to triclopyr acid (EPA, 1998). Available avian toxicity data for triclopyr butoxyethyl ester (BEE), another triclopyr product available for use by the Program, demonstrates slight toxicity, with median lethal dose values ranging from 735 to 849 mg/kg for the bobwhite quail (EPA, 1998). These values are well above any residues that would occur due to Program applications. Triclopyr TEA is not toxic to honey bees based on acute contact studies (EPA, 1998). Triclopyr TEA does exhibit toxicity to some terrestrial plants based on results from seedling emergence, germination, and vegetative vigor studies. The primary degradation product of triclopyr TEA, triclopyr acid, is similar in

toxicity to terrestrial nontarget organisms based on the available toxicity data.

TEA toxicity to aquatic organisms is low for fish and aquatic

invertebrates. Available acute fish toxicity data demonstrates median lethal concentrations greater than 100 mg/L for Garlon®3A and

technical triclopyr TEA (Wan et al., 1987; EPA, 2014a). Triclopyr TEA is not considered toxic to aquatic invertebrates in freshwater and marine environments, with toxicity values exceeding 300 mg/L. Chronic

toxicity to fish and aquatic invertebrates is also low with chronic toxicity no observable effects concentration (NOEC) ranging from approximately 80 mg/L to greater than 100 mg/L, depending on the test organism and endpoint. Although Triclopyr BEE may be toxic to aquatic invertebrates and fish, they will not be exposed to levels that could result in adverse effects from applications made by the Program. The primary metabolite of triclopyr TEA and BEE, triclopyr acid, is not considered toxic to aquatic organisms, based on available toxicity data (EPA, 1998, 2014a). For foliar treatments, Garlon® 3A is proposed for use as a mixture with the active ingredients imazapyr and metsulfuron-methyl. Imazapyr is an imidazolinone herbicide while metsulfuron-methyl is a sulfonylurea herbicide, with both products used as a mixture with triclopyr in the control of woody vegetation.

The toxicity of imazapyr and metsulfuron-methyl is considered low for mammals. The formulation containing metsulfuron-methyl, Escort® XP, is not considered toxic to mammals via inhalation, dermal, and oral exposures. All toxicity values were reported as greater than the highest test concentration. In addition, metsulfuron-methyl is not considered to

be carcinogenic, nor has it been shown to be a reproductive, teratogenic, or developmental hazard (Klotzback and Durkin, 2004). Escort® XP is considered a slight eye irritant, but is not considered a skin irritant or sensitizer. The other herbicide in the mixture, Arsenal®, containing the active ingredient imazapyr, has a similar mammalian toxicity profile to metsulfuron-methyl, and is considered practically nontoxic in acute inhalation, dermal, and oral exposures. Imazapyr is not considered a carcinogen or mutagen, and is not known to be a reproductive, teratogenic, or developmental hazard (Durkin and Follansbee, 2004). The toxicity of imazapyr and metsulfuron-methyl is low to all nontarget organisms, with the exception of some aquatic and terrestrial plants. Neither product is considered toxic to mammals, birds, or terrestrial invertebrates (Durkin and Follansbee, 2004; Klotzback and Durkin, 2004; EPA, 2014a). Toxicity to fish and aquatic invertebrates is very low, with median lethal acute concentrations typically exceeding 100 mg/L for both chemicals (Durkin and Follansbee, 2004; Klotzback and Durkin, 2004; EPA, 2014a). Chronic toxicity to fish and aquatic invertebrates is also considered low, based on the available NOECs that were reported from standardized toxicity studies.

Exposure to terrestrial and aquatic nontarget organisms is expected to be minimal from each proposed formulation and mix. Significant drift or runoff is not expected as applications are not broadcast applied, but are made using either a backpack sprayer to deliver a coarse droplet size, or by brushing the material on individual stumps and associated sprouting vegetation. The low probability of offsite transport for any of the products results in very low exposure to most nontarget organisms. The low

probability of exposure and the favorable available effects data demonstrate that all products have a very low risk of causing adverse ecological risk (see appendix E). Risk to nontarget organisms is greatest for plants as they are the most sensitive group to each application; however, the application methods and label directions minimize impacts to terrestrial plants, restricting potential harm to those plants that are immediately adjacent to treated stumps or sprouts. Exposure in aquatic systems is not expected to occur at levels that could result in any direct impacts to aquatic plants, or at levels that would suggest indirect impacts to aquatic organisms that depend on aquatic plants as a food source or as habitat. (Appendix E provides the risk assessment for herbicides the Program proposes to use.)

d. Economic, Social, and Cultural Resources

As described in the environmental consequences section for the no action alternative, ALB-host trees are important to the forestry products industry and their loss, particularly on forested lands, would result in negative

economic impacts. The Program removes and chips infested trees, making them unavailable to the timber and forestry products industry. ALB larvae create tunnels or galleries inside the tree, damaging the structural integrity of the wood. It is possible that lightly infested trees could have

salvageable wood for timber and other end-use products; however, the Program does not allow the diversion of infested trees from chipping to saw mills because of the risk of spreading ALB.

One maple tree can produce 10 to 60 gallons of sap for maple syrup in one season, depending on the tree (including size), weather conditions, length of sap season, and the method of collecting sap

(http://maple.dnr.cornell.edu/index.html). Maple syrup producers can absorb a loss of a percentage of maple trees but, depending on the size of the producer, there is a threshold where economic loss would shut down the business. APHIS does not recommend replacing maple trees with ALB-host trees in an area infested with ALB; therefore, replanting would not be an option for maple producers.

The impact to landowners is similar to those described under the

environmental consequences for the no action alternative. However, the Program will remove infested trees rather than leaving them to die in place. In the early stages of infestation, trees can appear healthy and continue to provide the aesthetic qualities and other benefits. Trees decline and die at different rates, depending on type of tree, its size, the population of ALB, exposure to other stressors, and other factors. Symptoms occur in approximately 3 to 4 years after infestation, and tree death can occur in 10 to 15 years, depending on site conditions. The Program would remove trees at all stages of infestation. This alternative would slow the spread of ALB; however, due to the difficulties in identifying infested trees, it is likely that some infested trees would be missed and, therefore, ALB would spread.

(1) Human Health

Under this alternative, the overall rate of tree loss from ALB infestation is expected to be reduced from the no action alternative because the Program removes infested trees, which reduces the ALB population and spread to other host trees. However, tree removal activities would initially cause an increase in tree loss, compared to the no action alternative where infested trees remain in place to die from ALB-infestation. In the short term, tree removal activities may result in increased noise levels (from use of mechanical equipment and increased traffic), increased stress (from decreased property values), increased cooling and heating costs, and other localized negative human health consequences from a lack of trees, (as discussed in the no action alternative) to the general public living in the infested areas. In the long term, the negative human health consequences

could be less than those compared to the no action alternative because the overall tree loss is expected to decrease to some degree.

(2) Herbicide Use

APHIS evaluated the risk to workers and the general public from the Program use of the three herbicides (appendix E). Two triclopyr

formulations, Garlon® 3A (active ingredient is TEA) and Pathfinder® II (active ingredient is BEE), for the treatment of stumps were analyzed. Pathfinder® II is used to treat the bark instead of direct application to cut areas of the stem. Minor foliar applications of Garlon® 3A mixed with two other herbicides, imazapyr and metsulfuron-methyl, are used to treat sprouting foliage from stumps that have been removed as part of the eradication program. The applications are made by hand either by brushing undiluted material on the stump or directly spraying stumps and/or sprouting foliage using a backpack sprayer. The TEA formulation can cause significant eye irritation, but has low acute inhalation and dermal toxicity. Acute oral median lethal concentrations range from approximately 600 to 1,000 mg/kg, suggesting low to moderate toxicity (Durkin, 2003).

Long-term toxicity studies have shown that triclopyr TEA is not a carcinogen or mutagen, and that toxicity in developmental and

reproductive studies primarily occurs at high doses, and at levels that are also maternally toxic (EPA, 1998). The concentrations at which these effects have been reported would not occur under normal program uses. The other proposed BEE formulation, Pathfinder® II, can cause slight temporary eye irritation during application, and some skin irritation under prolonged exposure. Acute oral median lethal concentrations are

1,000 mg/kg, with acute inhalation and dermal toxicity median lethality values greater than the highest test concentration, suggesting low acute mammalian toxicity under various exposure pathways. Triclopyr BEE is not considered carcinogenic or mutagenic and, in cases where

developmental and reproductive studies demonstrate effects, doses were at levels considered maternally toxic. The concentrations at which these effects have been reported would not occur under normal program uses. TEA breaks down in soil (~12 days) to triclopyr acid, and to a lesser extent, triethanolamine. Triclopyr BEE has low water solubility, and adsorbs more strongly to soil when compared to the amine. Triclopyr BEE also breaks down quickly to triclopyr acid in soil and water, with hydrolysis half-lives of less than 1 day. Imazapyr degradation and

dissipation half-lives are variable, ranging from approximately 25 days to greater than 300 days. Metsulfuron-methyl half-lives in soil range from 17 to 180 days. The use of these herbicides may negatively affect

sensitive individuals or those who inadvertently become exposed;

however, these herbicides are relatively short lived in the environment so any health effects from herbicide use are likely to be temporary.

The human health risk assessment results show that using triclopyr, or using triclopyr and mixing it with imazapyr and metsulfuron-methyl to control ALB populations should pose minimal risks to human health for workers and the general public (appendix E).

In addition, notification to landowners also occurs in the case of any chemical treatments that may be used to kill stumps (herbicides), as well as other label risk reduction requirements for herbicide use that are designed to protect workers, the general public, and the environment.

a. Forest Resources

Host trees within a ½-mile radius of an infested tree are at risk of ALB infestation because they are within the dispersal range of the beetle. Under the full host removal alternative, removal by the Program of both infested trees and high-risk host trees would occur. Depending on the density of host trees in the quarantine area, this will likely translate to the removal of a larger population of trees compared to the no action

alternative and two of the eradication alternatives. The intent is to protect urban and rural forests from ALB through the removal of host trees potentially infested with ALB but not at detectable levels.

The impacts to forestry resources, as described in alternative 2, could also occur under this alternative. Trees infested with ALB typically die within 10 to 15 years. Full host removal by the Program prematurely eliminates