Back to Table of Contents
APPENDIX D
MATRIX AND GROUP STAND SIMULATION

Introduction

The attached simulations provide insight into stands managed by group selection uneven-aged management. The Western Sierra Nevada Prognosis Variant (WESSIN) of the Forest Vegetation Simulator (FVS) was used to generate numerical stand summaries; the Stand Visualization System (SVS) was used to produce the visual aids. (SVS is a separate system which can use output generated from FVS.)

Selected Stands

Three vegetation types and prominent strata were selected for simulation. Detailed strata descriptions are in the Appendix B. Keep in mind, the management scenarios and selected stands represent a very small sample of possible actions. Selected strata are:

1. East-side pine - E or J regional vegetation type. East-side pine represents approximately 368,000 acres in the pilot project area. Within the E or J type, E3N is a common size and density. E3N can be best described as east-side pine, small sawtimber, and moderately stocked.

2. Mixed conifer - M regional vegetation type. Mixed conifer occupies approximately 254,000 acres of the pilot forested area. Of this, M3N comprises 97,000 acres of the M type.

3. Red fir - R regional vegetation type. Red fir occupies approximately 144,000 acres in the pilot area with 36,000 acres classified as R3N.

For each strata, a representative cluster plot was selected from the most recent inventory for each strata. Each of these cluster plots was a proxy for a possible stand condition.

Management Scenarios

Matrix lands. Both M3N and R3N strata are considered suitable owl habitat. CASPO guidelines were modeled for initial treatments during the pilot period for selected stands in these strata. Subsequent treatments were thinning from below with no trees greater than 30 inches in diameter harvested. These treatments were simulated visually for only the first 6-7 decades. E3N strata is not considered suitable owl habitat. For the initial treatment and all subsequent treatments of E3N, no trees greater than 30 inches in diameter were harvested. Again all thinning was from below. Treatments, if possible, were scheduled every 20 years to match the group selection schedule.

Group Selection. For M3N and R3N stands, residual overstory was designed to leave the largest five trees per acre. This is an attempt to simulate the average number of residual trees per acre remaining when the most optimum locations for groups have been determined. No attempt was made to change this criterion for outyear cycles even though we realize that finding suitable group locations will become more difficult with time under CASPO. To the extent possible, subsequent treatments within each group were scheduled at 20-year intervals. For subsequent thinnings, treatments within the groups left the residual trees in place and removed no trees greater than 30 inches in diameter. In the E3N stand, a residual overstory of the two largest trees was left. Again this was determined to simulate a likely management decision. Stand summaries and visual aids follow. For each stand, a brief discussion is included.

E3N STAND

Objective of Treatments. Eastside pine is usually grows in high fire risk areas. The objective of this treatment scenario is to aggressively thin such stands to create an open appearance. The modeling does not show active salvage of dead trees nor active treatment of downed materials. The reader can easily interpret stand appearance with or without salvage/fuels treatment. Treatments were also somewhat forced into 20-year intervals to allow the group selection harvest and matrix thinning at the same time while allowing for good timber sale opportunities.

Summary of Treatments. Group selections were established starting in year 2000. All trees greater than 30 inches were not harvested (2 trees per acre). A management cycle of 20 years was assumed. The stand would be entered every twenty years to establish more group selection openings. Existing group selection openings and matrix will be thinned, if feasible. Groups of east side pine are not expected to be thinned for about 60 years (the result of edge effect and some residual overstory). Large tree retention (trees greater than 30 inches in diameter) will be assumed to be a management desire. Good commercial timber sale opportunities in the matrix appear to be available for 2020, 2040, and 2060. Trust funds from timber sale receipts should help fund fuel treatment.

Refer to the following table and cross-referencing to the attached stand tables and visual simulations, to help visualize stand appearance. Assume the average opening is 1.5 acres and stand size is 100 or 1000 acres. The table below lists the acreage percentage and visual reference to "after treatment" appearance. In other figures, the reader can see how the stand looked at the beginning of the cycle prior to treatments (10-year period). When stand treatment data is displayed, 10 years of change elapsed since the last "snapshot." SVS thus works in the same manner. The "snapshots" are labeled with the same year as the treatment.

Table D1 Percentage of Land by Group Opening and Matrix
Year New Groups
Figure 2
Groups - 20
Years Old
Figure 3
Groups - 40
Years Old.
Figure 4
Groups - 60 
Years Old.
Figure 6
Matrix and
Figure 
Number
2000 11.4 0
0
0
88.6 Fig 1
2020 11.4 11.4
0
0
77.2 Fig 8
2040 11.4 11.4
11.4
0
65.8 Fig 10
2060 11.4 11.4
11.4
11.4
54/4 Fig 12


 

M3N STAND

Objective of Treatments. The objective of this treatment scenario is to thin for stand vigor. The group residual stocking was forced to 5 trees per acre all of which are greater than 30 inches in diameter. This was done to simulate more of what is perceived to be an average residual stocking. Management desire will be to retain all large trees (greater than 30 inches) for subsequent thinnings. Treatment scheduling was somewhat forced into 20 year intervals so as to allow for group selection harvest and matrix thinning at the same time thus allowing for good timber sale opportunities.

Summary of Treatments. Group selection openings were established starting in year 2000. A man-agement cycle of 20 years is assumed. Every 20 years the stand will be entered to establish more group selection openings. Thinning existing group selection openings and matrix will be done if feasible. Be-cause of the residual overstory and edge effect, commercial thinnings within the groups is not expected to occur until 2060. In the matrix, good commercial thinning timber sale offerings will occur in 2020, 2040, and 2060. Trust funds from timber sale receipts should help fund the treatment of fuels.

The reader can visualize the stand appearance by referring to the following table and cross referenc-ing to the attached stand tables and visual simulations. For interpretation convenience, assume the stand to be 100 or 1000 acres. One can also assume the average opening to be 1.0 acre. The table below lists the acreage percentage and visual reference for after treatment appearance. In other figures attached, the reader can see how the stand looked prior to treatments. Of note, FVS conducts treatments at the begin-ning of a cycle (10 year period). When stand data is displayed for treatments, 10 years of change will have occurred before another “snapshot” of the stand is taken. SVS works in the same manner. The la-beling of the following visual aids for after treatment snapshots carries the same year as the treatment.


 

R3N STAND

Objective of Treatments. The objective of this treatment scenario is to thin for stand vigor. The group residual stocking was forced to 5 trees per acre all of which are greater than 30 inches in diameter. This was done to simulate more of what is perceived to be an average residual stocking. Management desire will be to retain all large trees (greater than 30 inches) for subsequent thinnings. Treatment scheduling was somewhat forced into 20 year intervals so as to allow for group selection harvest and matrix thinning at the same time thus allowing for good timber sale opportunities.

Summary of Treatments. Group selection openings were established starting in year 2000. A management cycle of 20 years is assumed. Every 20 years the stand will be entered to establish more group selection openings. Thinning existing group selection openings and matrix will be done if feasible. Be cause of the residual overstory and edge effect, commercial thinnings within the groups is not expected to occur until 2060. In the matrix, commercial thinning timber sale offerings will occur in 2020, 2040, and 2060. Trust funds from timber sale receipts should help fund the treatment of fuels.

The reader can visualize the stand appearance by referring to the following table and cross referencing to the attached stand tables and visual simulations. One can also assume the average opening to be 0.75 acres. For interpretation convenience, assume the stand to be 100 or 1000 acres. The table below lists the acreage percentage and visual reference for after treatment appearance. In other figures attached, the reader can see how the stand looked prior to treatments. Of note, FVS conducts treatments at the beginning of a cycle (10 year period). When stand data is displayed for treatments, 10 years of change will have occurred before another ‘snapshot” of the stand is taken. SVS thus works in the same manner. The labeling of the following visual aids for after treatment snapshots carries the same year as the treatment.


 

Back to Table of Contents