Variables |
Ancotrema voyanum |
Helminthoglypta talmadgei |
Monadenia churchi |
Monadenia fidelis klamathica |
Monadenia fidelis ochramphalus |
|||||||||
|
Occupied |
Absent |
Occupied |
Absent |
Occupied |
Absent |
Occupied |
Absent |
Occupied |
Absent |
||||
Pecentage Conifer Cover |
58.17 (29.20) |
54.50 (29.13) |
36.63 (32.53) |
56.44 (30.28) |
50.20 (31.51) |
48.30 (31.59) |
67.11 (26.68) |
48.38 (28.82)* |
50.88 (33.42) |
57.00 (30.11) |
||||
Percentage Hardwood Cover |
59.88 (40.89) |
43.33 (39.77) |
51.25 (32.50) |
50.29 (41.87) |
57.78 (40.23) |
31.66 (39.24)* |
71.89 (35.46) |
39.81 (42.14)** |
72.50 (27.11) |
37.44 (39.58)** |
||||
Percentage Grass Cover |
3.00 (5.71) |
7.68 (13.35)** |
15.13 (12.99) |
3.93 (6.24)** |
5.51 (7.34) |
7.65 (11.65) |
2.78 (4.97) |
4.32 (8.00) |
4.88 (5.17) |
4.89 (8.26) |
||||
Conifer Basal Area |
42.58 (23.20) |
29.68 (21.91)** |
20.92 (20.89) |
31.48 (19.65) |
26.82 (20.24) |
25.93 (19.96) |
34.46 (16.21) |
27.07 (21.88) |
25.39 (15.68) |
33.60 (21.44) |
||||
Hardwood Basal Area |
13.89 (11.70) |
10.10 (12.30) |
6.57 (6.33) |
11.02 (11.46) |
11.42 (10.66) |
6.26 (9.26)** |
23.67 (18.44) |
10.00 (12.70)* |
13.94 (7.39) |
8.84 (12.57) |
||||
Quercus Basal Area |
0.38 (0.74) |
1.13 (2.07)* |
1.37 (0.78) |
0.90 (1.75) |
2.17 (2.58) |
1.23 (2.35)** |
1.16 (1.71) |
0.45 (1.45) |
0.65 (0.70) |
0.57 (1.40) |
||||
Acer Basal Area |
0.13 (0.28) |
0.16 (1.12) |
0.01 (0.02) |
0.04 (0.12) |
0.08 (0.29) |
0.11 (1.01) |
0.11 (0.33) |
0.05 (0.19) |
0.16 (0.35) |
0.04 (0.17) |
||||
Mean Tree Age |
185.66 (63.86) |
124.74 (75.37)** |
94.91 (76.27) |
140.93 (60.35) |
107.23 (63.06) |
115.39 (71.39) |
142.82 (56.58) |
133.09 (83.44) |
150.22 (98.82) |
129.60 (74.50) |
||||
Standard Deviation of Tree Age |
94.25 (56.04) |
74.74 (54.55) |
45.89 (52.41) |
76.69 (45.14) |
61.47 (43.98) |
65.32 (56.58) |
84.71 (24.60) |
70.94 (62.64) |
67.01 (57.46) |
70.39 (57.09) |
||||
Mean Conifer Diameter |
68.84 (19.57) |
45.99 (23.87)** |
51.65 (19.86) |
53.25 (18.30) |
41.34 (16.87) |
43.85 (19.50) |
47.57 (22.24) |
46.71 (26.69) |
54.35 (27.28) |
49.38 (21.62) |
||||
Mean Hardwood Diameter |
19.32 (15.33) |
19.32 (15.41) |
19.88 (6.92) |
15.12 (13.24) |
17.91 (13.59) |
15.84 (18.65) |
19.32 (6.21) |
13.39 (12.73)** |
19.62 (7.60) |
13.67 (11.10)* |
||||
Mean Hardwood Height |
9.50 (6.52) |
8.81 (5.87) |
9.57 (1.97) |
6.84 (5.22)** |
6.97 (4.11) |
5.94 (6.52) |
12.80 (2.63) |
7.12 (6.05)** |
9.45 (2.65) |
7.26 (5.51)* |
||||
Volume of Large Downed Wood |
66.87 (52.16) |
47.36 (63.06) |
20.40 (24.09) |
36.82 (44.05) |
32.34 (36.81) |
27.86 (29.57) |
23.48 (23.00) |
46.11 (54.11)* |
51.28 (46.15) |
48.10 (57.86) |
||||
Volume of Small Downed Wood |
17.56 (7.25) |
13.68 (6.96)** |
13.06 (5.50) |
13.67 (7.39) |
14.08 (7.65) |
14.06 (8.66) |
13.77 (6.54) |
13.50 (6.64) |
12.79 (6.39) |
15.45 (7.26) |
||||
Total Volume of Downed Wood |
84.43 (53.22) |
61.04 (65.04)* |
33.47 (24.05) |
50.49 (47.65) |
46.43 (38.83) |
41.92 (34.75) |
37.25 (24.10) |
59.60 (56.30)* |
64.06 (46.32) |
63.54 (60.60) |
||||
Transformed Aspect |
0.39 (0.37) |
0.51 (0.38) |
0.69 (0.28) |
0.49 (0.36)* |
0.55 (0.33) |
0.51 (0.37) |
0.36 (0.38) |
0.45 (0.38) |
0.40 (0.40) |
0.46 (0.37) |
||||
Percentage Slope |
51.25 (19.85) |
47.38 (19.89) |
56.25 (15.06) |
50.73 (20.90) |
49.45 (18.20) |
41.86 (16.69)* |
46.67 (20.62) |
48.53 (19.57) |
47.50 (14.88) |
49.86 (19.38) |
||||
Elevation (m) |
975.61 (341.04) |
986.50 (385.75) |
952.74 (213.57) |
1135.48 (470.23)* |
1048.78 (404.83) |
1285.27 (419.08)** |
718.16 (343.28) |
947.81 (376.13)* |
788.87 (192.43) |
1040.45 (432.54)** |
||||
Mean Annual Precipitation |
166.82 (35.16) |
162.88 (43.66) |
119.11 (17.86) |
149.79 (34.50)** |
139.75 (34.96) |
139.54 (28.25) |
169.65 (35.64) |
206.27 (56.27)** |
154.15 (23.68) |
165.56 (55.67) |
||||
Mean Summer Precipitation |
7.88 (0.20) |
7.90 (0.28) |
7.67 (0.13) |
7.82 (0.21)** |
7.65 (0.24) |
7.66 (0.31) |
7.90 (0.23) |
8.16 (0.37)** |
7.82 (0.12) |
8.00 (0.31)** |
||||
CVPRE |
95.82 (0.90) |
95.31 (1.65)* |
94.00 (1.66) |
94.67 (1.53) |
95.43 (2.11) |
95.12 (2.02) |
96.10 (0.75) |
95.28 (1.40)** |
95.45 (0.70) |
93.87 (2.82)** |
||||
Mean August Maximum Temperature |
31.38 (1.45) |
30.40 (2.49)** |
31.46 (1.26) |
30.54 (2.27) |
30.72 (1.54) |
29.75 (2.51)** |
32.48 (0.89) |
29.34 (2.97)** |
31.62 (1.29) |
29.03 (2.84)** |
||||
Mean December Minimum Temperature |
-1.98 (0.91) |
-2.14 (1.33) |
-2.65 (1.30) |
-3.45 (2.01) |
-3.22 (1.76) |
-3.78 (1.88)* |
-0.97 (1.40) |
-1.39 (1.26) |
-1.39 (0.99) |
-2.24 (1.28)** |
||||
August Max. Temp - Dec. Min. Temp. |
33.36 (1.28) |
32.54 (2.53)** |
34.11 (0.36) |
33.99 (0.79) |
33.94 (0.93) |
33.53 (1.04)** |
33.45 (0.72) |
30.73 (3.25)** |
33.01 (1.19) |
31.27 (2.94)** |
||||
Mean Summer Temperature |
17.72 (1.00) |
17.04 (1.43)** |
17.50 (1.24) |
16.76 (1.88) |
16.74 (2.05) |
15.99 (2.02)** |
18.77 (0.87) |
16.97 (1.53)** |
18.25 (0.86) |
16.67 (1.55)** |
||||
SMRTSMRP |
81.19 (3.51) |
79.53 (4.98)* |
82.82 (3.63) |
79.42 (5.89)* |
81.27 (4.825) |
79.60 (7.06)* |
83.39 (4.05) |
76.96 (6.21)** |
82.99 (2.01) |
77.71 (5.27)** |
||||
Young forest† |
0 |
23 |
1 |
8 |
13 |
30 |
1 |
20 |
0 |
22 |
||||
Mature forest† |
11 |
42 |
5 |
24 |
34 |
56 |
5 |
30 |
5 |
30 |
||||
Old-growth forest† |
13 |
19‡ |
2 |
9 |
8 |
13 |
3 |
18 |
3 |
20 |
Note: The last three rows represent the number of plots classified as young, mature, or old-growth forest by a modified version of the model developed by Bingham and Sawyer (1991).
†The Discriminant Function Analysis (DFA) model developed by Bingham and Sawyer (1991) used eight variables. We had available to us four of those variables from the Forest Inventory and Analysis data (basal area of conifers > 90 cm dbh; basal area of conifers >45 cm dbh; density of hardwood snags > 20 cm dbh; and basal area of hardwoods 45-90 cm dbh). Bruce Bingham (USDA Forest Service, Region 6) re-ran the original data from Bingham and Sawyer (1991) with this reduced variable set, then used the resulting model to classify the FIA plots within our study area. The reduced-variable DFA model had jack-knifed correct classification rates of 86% for young and mature forests, and 97% for old-growth forests using their original data. We conducted a chi-square goodness-of-fit test to evaluate the association of each species to young, mature, and old-growth forests using this classification.
‡=significant association ( = 12.91, df = 4, P = 0.044), primarily due to fewer plots than expected in young forest being occupied and more plots in old-growth forest than expected being occupied.
* = P < 0.10, ** = P < 0.05.
Literature cited
Bingham, B. B., and J. O. Sawyer. 1991. Distinctive features and definitions of young, mature, and old-growth Douglas-fir/hardwood forests. Pages 363–378 in L. F. Ruggerio, K. B. Aubry, A. B. Carey, and M. H. Tuff, Technical Coordinators. Wildlife and vegetation of unmanaged Douglas-fir forests. U.S. Department of Agriculture, Forest Service, General Technical Report PNW-GTR-285, Portland, Oregon, USA.