Appendix F Pactola Project Area Silviculture Findings and CMAI 

APPENDIX F 

SILVICULTURE FINDINGS 

AND 

CMAI

Appendix F Pactola Project Area Silvicultural Findings and CMAI F-3 

APPENDIX F – PACTOLA PROJECT SILVICULTURAL FINDINGS AND CMAI 

Relative to Silvicultural Compliance with Laws, Regulations, and Policy. 

Pactola Project 

The following findings are made based on the environmental analysis and the silvicultural 

prescription: 

Best Science Findings: 

While conducting my analysis for the Pactola Project I reviewed information from the following 

sources: 

1. Black Hills National Forest Monitoring Report, FY2009. 

2. Phase II Final EIS (FEIS), applicable supporting documents, and applicable literature 

references, as follows: See Pactola Silviculture Report Bibliography. 

3. Applicable research which I believe represents a reasonable cross-section of the total range 

available, including responsible opposing views, sufficient to professionally evaluate the effects 

of this proposal, as follows: See Pactola Silviculture Report Bibliography. 

4. Literature sources offered in comments provided on this project analysis, as follows: See 

Pactola Silviculture Report Bibliography. 

5. Other sources, as follows: See Pactola Silviculture Report Bibliography. 

In considering these sources I believe I have considered the best science available to me. 

Consistency [16USC1604(i)]: 

1. Timber harvest would occur on lands suited for timber production or would occur in areas 

where timber harvest is permitted and is necessary to help achieve other resource management 

objectives: 

Table F1. Alternative B Treatment/Suitability Summary 

Treatment/Suitability MA 5.1

Acres

MA 5.4

Acres

MA 8.2

Acres

MA 3.7

Acres

Total

Acres

Commercial Thinning/Suitable 1,979 2,521 1,227 0 5,727 

Commercial Thinning/Permitted 0 0 123 372 495 

Shelterwood Seed Cut/Suitable 96 91 0 0 187 

Removal Cuts/Suitable 164 663 0 0 827 

Hardwood Treatments/ Suitable 47 682 32 0 761 

Hardwood Treatments/ Permitted 149 750 24 13 936 

Meadow Treatments/ Permitted 123 48 162 102 435 
Appendix F Pactola Project Area Silvicultural Findings and CMAI F-4 

Table F2. Alternative C Treatment/Suitability Summary 

Treatment/Suitability MA 5.1 

Acres

MA 5.4 

Acres

MA 8.2 

Acres

MA 3.7 

Acres

Total 

Acres

Commercial Thinning/Suitable 2,195 2,669 1,566 0 6,430 

Commercial Thinning/Permitted 0 0 123 423 546 

Shelterwood Seed Cut/Suitable 126 91 0 0 217 

Removal Cuts/Suitable 197 843 0 0 1,041 

Hardwood Treatments/ Suitable 149 749 32 0 930

Hardwood Treatments/ Permitted 182 750 24 13 969

Meadow Treatments/ Permitted 148 48 162 102 460 

Cable/Suitable 0 339 29 0 368 

Cable/Permitted 178 91 632 0 901

Roadside Treatments/Suitable 112 237 87 0 436 

2. Silvicultural treatments are consistent with the Forest Plan. 

Prescriptions used in development of alternatives in the Pactola Project area are generally evenaged and include thinning, shelterwood overstory removal, weeding, and pine encroachment 

removal in meadows and hardwoods. Even-aged regeneration harvests are appropriate to 

meeting the objectives and requirements of the Forest Plan. There are also some stands which 

will be managed using uneven-aged systems. Forest Plan Standard 2408 a. states that “both 

even-aged and uneven-aged management systems can be used and applied at scales ranging from 

a few acres to many hundreds of acres”. 

Prescriptions were developed to achieve Forest Plan (Phase II Amendment) Goal 10: Establish 

and maintain a mosaic of vegetation conditions to reduce occurrences of high intensity fire, 

insect, and disease events, and facilitate insect and disease management and firefighting 

capability. In addition they were designed to comply with the Healthy Forest Restoration Act 

(HFRA) of 2003 (HR 1904) and other National level initiatives and policy that emphasize 

reducing the probability and occurrence of severe wildfire in fire adapted ecosystems, especially 

near at risk communities (ARC) and in the wildland-urban interface (WUI). 

Timber Harvest [16 U.S.C. 1604 (g) (3) (E)]: 

 

1. Soil, slope, or other watershed conditions will not be irreversibly damaged. Refer to Soils 

report and hydrology report. Also, refer to mitigation/monitoring section of the Pactola EIS. 

2. There is assurance that the lands can be adequately restocked within five years after final 

regeneration harvest. All stands within the project area to receive shelterwood removals can be 

adequately restocked within 5 years of harvest. The minimum tree stocking standards for Region 

2 will be met. Region 2 minimum stocking standards are described in FSH 2409.26b 

Reforestation Handbook R2 Amendment No. 2409.26b - 93-2. 

3. Streams, stream banks, shorelines, lakes, wetlands, and other bodies of water are protected 

from detrimental changes in water temperatures, blockages of water courses, and deposits of 
Appendix F Pactola Project Area Silvicultural Findings and CMAI F-5 

sediment where harvests are likely to seriously and adversely affect water conditions or fish 

habitat. Refer to hydrology report. 

4. The harvesting system to be used was not selected primarily because it will give the greatest 

dollar return or the greatest unit output of timber. 

Even-aged Regeneration Harvests [16 U.S.C. 1604 (g) (3) (F)]: 

1. Shelterwood regeneration harvests are appropriate to meeting the objectives and requirements 

of the Forest Plan. Shelterwood Overstory Removals will be used as specified in the Black Hills 

FEIS, Phase II Amendment Chapter II, pg. 26. 

2. An interdisciplinary review was completed and the potential environmental, biological, 

aesthetic, engineering, and economic impacts were assessed and the cutting methods are 

consistent with the multiple use of the project area as specified in the Pactola Project EIS and 

Record of Decision. 

3. Cut blocks, patches, or strips are shaped and blended to the extent practicable with the natural 

terrain. 

4. Even-aged regeneration harvests made in one operation meet the 40-acre maximum size limit 

requirement. Forest Plan Standard 2101, Phase II FEIS (Chapter II pg. 17). 

5. Harvest will be consistent with the protection of soil, watershed, fish, wildlife, recreation, 

esthetic resources, cultural and historic resources, and the regeneration of timber resources. See 

specific resource specialist’s reports. 

Culmination of Mean Annual Increment [16 U.S.C. 1604 (m)]: 

Determination of Culmination of Mean Annual Increment (CMAI) 

The stands or portions of stands receiving shelterwood regeneration harvest treatments have 

generally reached the culmination of mean annual increment (CMAI). Per the 1997 Forest Plan, 

stands which have reached an age of 120 years have reached CMAI. It should be noted that 

some of these stand’s total age is less than 120 years but larger trees within that stand have 

reached 120 years; therefore, CMAI is met in these stands. Silvicultural prescriptions were 

developed while considering NFMA requirements about the timing of harvests. 16 USC 1604(i) 

states "stands of trees scheduled to be harvested during the planning period shall generally have 

reached culmination of mean annual increment of growth". The calculation of CMAI is based on 

the total amount of biomass accumulated in a stand to a specific date divided by age. Because 

stand age must be known, MAI can only be calculated for even-aged or multi-aged stands, but 

not uneven-aged stands. CMAI is calculated at the stand level, and not on individual trees. 

Even-aged harvests include clearcuts and shelterwood harvests. It is the accepted practice in the 

forestry profession to apply the CMAI standard to the timing of the regeneration step of evenaged harvests. For a two-step shelterwood, the determination is made at the seed step, and not the 

overstory removal step. 
Appendix F Pactola Project Area Silvicultural Findings and CMAI F-6 

16 USC 1604(i) allows cultural practices or stand tending, such as commercial or precommercial 

thinning, to occur prior to CMAI. It also allows harvest to occur prior to CMAI "if it is reasonable 

to expect that overall multiple use objectives would be better attained." Therefore, it doesn't apply 

to the clearcuts and seed cuts of conifers in the Black Hills to benefit species, provide diversity, 

recreation, scenic variety or forage. (These exceptions are disclosed and decided upon at the 

project level). It also doesn't apply for non-commercial treatment of hardwoods. 

Although it is possible to approximate CMAI at the planning level (forest-wide) for the purpose 

of establishing a rotation age, this is not be confused with the stand CMAI requirement, which is 

the only requirement established by law, and which is actually measured/calculated on a stand 

basis. Because of the complexities of the calculation, CMAI can be accurately determined only at 

the project level. 

Although not legally required, for the purposes of establishing general rotation ages in FVS 

simulations, and to assure that the Forest Plan can be implemented, an analysis of approximate 

ranges of CMAI in the Black Hills was made. Although the CMAI determination is not 

straightforward, timber harvests used to implement the Revised Plan will generally be able to 

meet the legal requirement. 

Growth curves developed for FVS are not appropriate for determining CMAI. The curves 

include the growth of smaller aged cohorts of the strata. They also do not take into account the 

volume of trees that have been harvested in previous entries. 

The age at CMAI will vary depending on site quality, forest type, management intensities and 

utilization standards, but various analyses indicate that it generally will occur for most stands 

between 80 and 120 years for conifer sawtimber in the Black Hills. Timing of regeneration 

harvests for stands specified in FVS simulations fall within or exceed this range. An analysis of 

the truly even-aged Stage I plots (4 out of 257 sawtimber and 5 out of 56 pole plots) shows that 

the CMAI varied between 88 and 136 years with an average of 108 years. 

The silvicultural system most commonly used for ponderosa pine in the Black Hills is the 

shelterwood system, which is an even-aged system and an acceptable system as specified in the 

Phase II FEIS (Chapter II, pg. 25). Most of the overstory removal cuts are in multi-aged stands 

or stands that have advanced regeneration. These treatments can also be considered as liberation 

cuts or stand improvement cuts. The stands listed in Table A3 and Table A4 are proposed for 

removal cuts in Alternatives B and C. 

Table F3. Alternative B 

Stand B_ALT Acres CMAI Stand B_ALT Acres CMAI

090101 12 OR 102 YES 090304 15 OR 29 YES

090101 19 OR 53 YES 090305 3 SC 35 YES

090101 23 OR 47 YES 090305 6 OR 42 YES

090101 29 OR 63 YES 090401 3 SC 35 YES

090101 35 OR 12 YES 090403 11 SC 7 YES
Appendix F Pactola Project Area Silvicultural Findings and CMAI F-7 

Stand B_ALT Acres CMAI Stand B_ALT Acres CMAI

090101 37 SC 19 YES 091401 18 OR 71 YES

090102 12 SC 27 YES 091403 2 OR 55 YES

090102 18 OR 28 YES 091403 13 OR 57 YES

090102 19 OR 51 YES 091403 23 OR 90 YES

090102 26 OR 17 YES 091501 19 SC 23 YES

090301 16 OR 46 YES 091503 14 SC 22 YES

090303 8 SC 19 YES 091503 16 OR 17 YES

090304 4 OR 13 YES

Table F4. Alternative C 

Stand C_ALT Acres CMAI Stand C_ALT Acres CMAI

090101 12 OR 102 YES 090303 8 SC 19 YES

090101 19 OR 53 YES 090304 4 OR 13 YES

090101 23 OR 47 YES 090304 15 OR 29 YES

090101 29 OR 63 YES 090305 3 SC 35 YES

090101 35 OR 12 YES 090305 6 OR 42 YES

090101 37 SC 19 YES 090401 3 SC 35 YES

090102 4 OR 43 YES 090401 5 OR 33 YES 

090102 6 OR 66 YES 090403 11 SC 7 YES

090102 12 SC 27 YES 091401 18 OR 71 YES

090102 18 OR 28 YES 091403 2 OR 55 YES

090102 19 OR 51 YES 091403 13 OR 57 YES

090102 24 OR 71 YES 091403 23 OR 90 YES

090102 26 OR 17 YES 091501 19 SC 23 YES

090301 16 OR 46 YES 091503 14 SC 22 YES

090303 5 SC 30 YES 091503 16 OR 17 YES

Findings prepared by: /s/Randall R. Rick Date: 12/17/2010 

Findings recommended by: /s/Randall R. Rick Date: 12/17/2010 

 Randall R. Rick 

 Certified Silviculturist 

Findings accepted by: /s/Robert J. Thompson Date: 1/24/2011 

 Robert J. Thompson 

 Mystic District Ranger