3. IMPACTS OF THE PROPOSED ACTION

This chapter is an analysis of the significant impacts of the proposed action upon the various resources as they exist today (described in Chapter 2). Analysis indicates that there would be no significant impacts upon climate, geology, topography, mining, agriculture, rural and urban lands, and transportation. Two categories of operations are involved: those required for harvest and those required for the assurance and augmentation of future timber crops. The operations are defined in the Glossary.

The 3-year (1980-82) timber sale plan (Appendix A) is used where applicable for site specific timber sale impacts. The plan contains estimates of volume to be harvested, types of logging methods to be used, miles of roads to be constructed, acres of slash to be burned, and soil association types to be affected within each sale area. All other timber management practices listed in Table 1-1 can only be analyzed from the 10-year timber management plan. Tree planting, precommercial thinning, fertilization, and gopher control projects would be developed and undertaken throughout the 10-year period based on identified needs.

Comparison of the 3-year timber sale plan to the 10-year proposed harvest level discloses significant average annual differences. Approximately 80 percent of the total overstory removal planned for the decade would be accomplished in the first 3 years. Conversely, only 8 percent of the final harvest and 10 percent of the commercial thinning sales would be accomplished in the first 3 years. An analysis of impacts for years 4 through 10 assumed that levels of the above three types of harvest would adjust to reflect the proposed decadal harvest level. Specific sale sites for fiscal years 1983 through 1989 are unknown.

A 1-year herbicide plan has also been prepared for the JKS YUs and is outlined in Appendix B. This is the fiscal year 1979 plan which is not fully representative since no spring spraying was accomplished. Since no herbicide use has been allowed for the past 3 years, a typical plan would show greater emphasis on removal of the backlog in site preparation and release applications. It is expected that the bulk of the backlog will be removed by the middle of the decade. The total area proposed for herbicide treatment is 29,690 acres as shown in Table 1-1.

Within the indicated constraints,

timber sale and herbicide plans provide

a means to quantify some of the treatments listed in Table 1-1 and facilitate impact analysis in this chapter.

The format of the analysis is similar to the format of Chapter 2 in that impacts are described under resource component headings. A brief summary

of impacts is provided with each major resource section. A tabular display of impacts, quantified to the extent possible, is also provided where appropriate. The degree of impact is determined by differences in impact intensity between the proposed plan and the existing plan (Section 1.6). Secondary impacts are identified and traced to the extent they can no longer be identified with the proposed action.

Two time frames are used in the analysis process. The short term is the first 10 years, the planned life of the proposed timber management plan. The long term is defined as in excess of 10 years. It is expected to take 50 years before all old growth is removed from commercial forest lands in the intensive management category. Other discrete time periods, pertinent to specific impact discussions, are used as necessary and are identified in the text.

A basic assumption of the analysis is that sufficient funding and manpower will be available for implementing the management plan as proposed. in many cases existing levels of resource data are limited and specific sites for proposed timber management activities. activities are not presently known for the 10-year plan period, both "most probable case" and "worst case" assessments are addressed in this chapter. It is further assumed that the herbicide projects proposed are submitted through an annual Departmental review process (described in Section 1.3.4.2) each year prior to approval of any project.

3.1 IMPACTS ON CLIMATE

All impacts of the management plan are to the microclimate rather than the climate of the JKSYUs. As a result of timber harvest, road construction, and development practices, soil temperature extremes would increase, relative humidity would decrease, and wind velocities would increase. Seedling mortality would increase somewhat as a result of such changes, although not a significant amount. Understory vegetation would tend to dry out more quickly in the dry season, which would be of significance during periods of fire danger. Loss of trees from wind throw would be insignificant since most of blowdown would be salvaged.

3.2 IMPACTS ON AIR QUALITY

Air quality would be significantly impacted by increased particulates produced during slash burning. The air pollution caused by additional vehicle emissions and volatilized herbicides and diesel oil carrier would not have significant impact upon the quality of the airshed when compared to additions from other sources.

To assess the impacts of slash burning on air quality in the JKSYUs the following assumptions were made:

(1) Project design features in Section 1.5.3.2 would be applied; that is, burning would not be allowed during periods of high air pollution and air stagnation.

(2)

Burning would occur only with permission from the Oregon State Department of Forestry. In the recent past, about 25 percent of planned burns have actually been conducted in the region (Personal Communication, Oregon Department of Forestry 1979).

(3) Burning may occur throughout the year.

IMPACTS ON AIR QUALITY

(4) All other factors contributing to air pollution in the JKS YUS would occur uniformly over the Southwest Oregon Air Quality Control Region.

(5)

Emissions from slash burning would be uniformly distributed over the

JKS YUS.

Essentially no slash burning has been done on the planning area over the past 5 years to October 1, 1977 (BLM File Data, OSO), and it is assumed that there would be no slash burning until the start of the proposal. Consequently, the proposed action represents an increase from no burning to 23,700 acres of burning over the 10-year time period, an average of 2,370 acres per year. After considering the amount of slash produced in forests of western Oregon, the type of timber that would be cut, the geographic location, the age of most of the trees, and the average reported ratios of weight to slash volume, the average weight of slash that would be burned annually was calculated to be 150 million pounds (75,000 tons) (Maxwell et al. 1976; Howard 1971; Dell et al. 1971).

Certain combustion products, including particulates, nitrogen oxides, carbon monoxides, and hydrocarbons, are used as indicators of air pollution from slash burning. The amount of each pollutant produced per ton of slash burned and the total amount that would be produced over 10 years by the proposed action is shown in Table 3-1. Approximately 26 percent of these pollutants would be produced in the first 3 years of the proposed action.

Since pollution from burning forest vegetation (wild fire and controlled burning) accounts for 23.7 percent of the particulate pollution, 6.9 percent of the hydrocarbon pollution produced annually in the United States (Sandberg et al. 1975), and 57 percent of the area-source particulate pollution in the AQCR (ODEQ 1976a), the burning of slash is rightly of concern.

The amounts of additional pollutants produced from slash burning would most likely be mixed by wind and dispersed (Table 3-1). Under the assumed management guidelines, no burning would be done on days when there was no atmopheric mixing or movement, thus the smoke would dissipate and reach background levels after traveling between 12 to 30 or 35 miles (Fritschen et al. 1970, U.S. EPA 1978).

Carbon monoxide production would increase but because concentrations drop rapidly with distance from the site (Fritschen et al. 1970), levels would not increase significantly throughout the planning area. Although burning would be controlled to minimize impacts, the increase in particulates would be significant in the JKS YUs. The effects of increased particulates would be reduced visibility in the area of the burn with subsequent impacts to esthetic values, as well as possible aggravation of chronic lung and heart diseases. Although the areas most affected by increased particulates are not heavily populated, residents and recreationists have come to expect higher air quality there than in urban areas and would be unfavorably affected.

Because neither the exact location of the proposed burns nor the time when the Oregon State Department of Forestry would allow burning is known, it

Amount of
slash that

would be

burned/year

Pollutant
produced by
burning slash

Table 3-1

Potential Air Pollution Caused by Slash Burning in the Proposal Area

Percent addi-
tional pollutant

from proposed
action compared
to that pres-
ently produced
by slash burning

6,262

30-90

1-4

1/

U.S. EPA 1978

2/ ODEQ 1976b (tons of pollutant / year X area JKSYUs)

area AQCR

IMPACTS ON SOILS

is

not possible to determine the increased frequency of violations of air quality standards as a result of slash burning.

3.3 IMPACTS ON SOILS

3.3.1 Erosion

The major source of soil erosion under the proposed action is from construction of new roads. Other minor sources which add up to a significant amount of erosion include yarding activities and slash disposal. Other management activities were found to cause little or no additional amounts of soil erosion. Planting Planting would significantly reduce soil erosion on previously understocked areas.

3.3.1.1 Road Construction and Maintenance

Forest roads have been recognized as the major cause of erosion resulting from silvicultural activities and of soil movement and stream siltation in western Oregon (Fredriksen 1970; U.S. EPA 1975; USDI, BLM 1959).

An estimated 375 miles of new permanent road would be constructed on 1,770 acres of relatively undisturbed lands. The erosion rate for the undisturbed lands in the JKS YUS is 35 tons per square mile per year (0.05 tons/acre/year) (Section 2.4). Construction of logging roads would increase erosion 220 times this figure (Megahan 1972), to 12.0 tons per acre per year, decreasing at a rate of 25 percent per year for 4 years to background levels. The total erosion due to new road construction would equal approximately 53,100 tons over the decade.

The number of miles of road requiring reconstruction and renovation would vary from year to year because factors such as the degree and intensity of use, extreme weather, and normal weather determine the need for reconstruction. Impacts of reconstruction activities are often similar to those of construction, although no new roads are added to the system. Based on an estimated 100 miles of reconstruction and maintenance, approximately 7,500 tons would erode over the 10-year period of the proposed action.

to

Analysis of the 3-year timber sale plan shows some construction of roads on unstable soils. Project design features would be used on these soils minimize erosion losses, but if they should fail, considerable soil erosion could occur. Table 3-2 indicates those sales where road failure could result in significant soil erosion. Because of lack of research in this region, it is not possible to quantify soil losses on a site-specific basis.

3.3.1.2 Yarding

Yarding increases erosion by disturbing and/or compacting the surface layers of soil. Tractor yarding would disturb and/or compact 13,625 acres (Table