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Table 1 Descriptions, possible values or units of measure, and means or counts of landscape conditions, forest features, forest management activities, and disturbance factors evaluated as potential factors of site invasion by Japanese stiltgrass in forest plots in Tennessee

From: Understory upheaval: factors influencing Japanese stiltgrass invasion in forestlands of Tennessee, United States

Variable

Value or unit of measure

Mean (range) for continuous data/count for categorical data

Landscape conditions

 Elevation

m

213.04 (− 28.04 to 1809.9)

 Slope

Degree

10.88 (0.00 to 57.5)

 Adjacency to water bodies

No

2138

 

Yes

665

Forest features

 Stand age

Years

55.42 (2 to 137)

 

L1: 0 to 1.39 m3/ha/year

0

 

L2: 1.40 to 3.39

256

 

L3: 3.50 to 5.94

1840

 Site productivity

L4: 5.95 to 8.39

802

 

L5: 8.40 to 11.54

290

 

L6: 11.55 to 15.74

78

 

L7: > 15.74

11

 Tree species diversity (Hs)

Shannon’s species diversity

1.88 (0 to 3.02)

 Basal area

m2/ha

22.53 (0.00 to 332.34)

 Natural regenerationa

No

3483

 

Yes

64

Forest management activities

 Site preparationa

No

3508

 

Yes

39

 Artificial regenerationa

No

3389

 

Yes

158

 Cuttinga

No

3270

 

Yes

277

 Forestland ownership

Public

486

 

Private

3061

Disturbance factors

 

D3: 92 to 152 m

354

 

D4: 153 to 305

578

 

D5: 306 to 805

777

 Distance to the nearest road

D6: 806 to 1609

333

 

D7: 1610 to 4828

116

 

D8: 4829 to 8047

11

 

D9: > 8047

7

 Fire disturbancea

No

3511

 

Yes

36

 Animal disturbancea

No

3478

 

Yes

69

 Disease disturbancea

No

3537

 

Yes

10

 Insect disturbancea

No

3421

 

Yes

126

 Human-caused disturbancea

No

3482

 

Yes

65

 Weather disturbancea

No

3470

 

Yes

77

  1. aNormally within the past 5 years