Images to illustrate various retention levels and patterns created using EnVision.

The original stand had 190 square feet of basal area and 117 trees per acre. Average dbh and height for the stand was 14.6 inches and 86.4 feet respectively. The stand is predominately Douglas-fir. Other species in the stand are western red cedar, western hemlock, and bigleaf maple. The original stand data was taken from the Pack Forest data. However, data associated with several stand polygons was modified to provide more uniform tree cover across the landscape.

Retention levels vary from 0% to 100% of the original basal area in 10% intervals.

Treatment Summary Data

Retention level

(Computed over entire 32.508 acre unit)

Retained trees distributed uniformly over the treatment unit

Retained trees in small groups

100% TPA: 204.8

Basal Area: 332.1

TPA: 204.8

Basal Area: 332.1

90% TPA:183.9

Basal Area: 298.9

TPA: 185.3

Basal Area: 298.9

80% TPA: 162.6

Basal Area: 265.7

TPA: 164.2

Basal Area: 265.6

70% TPA: 145.1

Basal Area: 232.5

TPA: 146.0

Basal Area: 232.4

60% TPA: 125.0

Basal Area: 199.3

TPA: 127.4

Basal Area: 199.2

50% TPA: 103.7

Basal Area: 166.1

TPA: 106.5

Basal Area: 166.0

40% TPA: 82.0

Basal Area: 132.8

TPA: 87.5

Basal Area: 132.8

30% TPA: 61.6

Basal Area: 99.6

TPA: 67.1

Basal Area: 99.5

20% TPA: 40.9

Basal Area: 66.4

TPA: 43.7

Basal Area: 66.3

10% TPA: 19.2

Basal Area: 33.2

TPA: 22.8

Basal Area: 33.1

0% TPA: 0

Basal Area: 0

TPA: 0

Basal Area: 0

Two retention patterns are illustrated: retained trees distributed uniformly over the treatment area and retained trees retained in small groups. For low retention treatments, trees appear to be scattered individuals instead of small groups.

Three viewpoints are used to provide replications of the treatment/spatial pattern combinations.

Viewpoint #1

Retention level

Retained trees distributed uniformly over the treatment unit

Retained trees in small groups

100% BA

90% BA

80% BA

70% BA

60% BA

50% BA

40% BA

30% BA

20% BA

10% BA

0% BA

Viewpoint #2

Retention level

Retained trees distributed uniformly over the treatment unit

Retained trees in small groups

100% BA

90% BA

80% BA

70% BA

60% BA

50% BA

40% BA

30% BA

20% BA

10% BA

0% BA

Viewpoint #3

Retention level

Retained trees distributed uniformly over the treatment unit

Retained trees in small groups

100% BA

90% BA

80% BA

70% BA

60% BA

50% BA

40% BA

30% BA

20% BA

10% BA

0% BA