Ecological Archives A025-070-A1

Brandon M. Collins, Jamie M. Lydersen, Richard G. Everett, Danny L. Fry, and Scott L. Stephens. 2015. Novel characterization of landscape-level variability in historical vegetation structure. Ecological Applications 25:11671174. http://dx.doi.org/10.1890/14-1797.1

Appendix A. Summary of topographic variables, derived canopy cover, and large tree density distributions.

Table A1. Summary of topographic/moisture availability variables used to predict the distribution of historical vegetation structure groups across the landscape.

Variable

mean

range

Elevation (m)

1393

776–2140

Slope (%)

9.1

0.7–39.2

Aspect (cosine transformed)

9.6

0.4–19.5

Topographic relative moisture index

30.4

12.5–49.8

Actual Evapotranspiration (mm)

450

276–565

Annual climatic water deficit (mm)

261

70–394

 

N transects

Topographic position (categorical, by majority area)

Valley bottom

22

Gentle slope

32

Steep slope

228

Ridge

12

 

Table A2. Estimated canopy cover for the nine historical vegetation groups identified from the k-means cluster analysis. Estimates were derived using the Forest Vegetation Simulator (Dixon 2002), which projects the percentage of ground area directly covered with tree crowns. This estimation corrects for crown overlap, based on species specific equations for crown radius (Dixon 2002).

Vegetation structure group

n

Derived canopy cover (%)

Shrub

27

0.1

Low BA, high shrub

48

9.4

Low BA, small trees

31

11.6

PIPO, low BA, high CHFO

44

15.7

PIPO, high BA, mod CHFO

41

23.8

PIPO-CADE, low CHFO

60

17.3

Mixed-conifer, large trees

24

28.3

PSME, mod shrub

16

20.3

ABIES, large trees

3

20.3

Average*

267

17.2

Species codes are as follows: CHFO-Chamaebatia foliolosa, ABCO-Abies concolor, ABMA-A. magnifica, CADE-Calocedrus decurrens, PILA-Pinus lambertiana, PIPO-P. ponderosa, and PSME-Pseudotsuga menziesii.
*does not include the shrub group in the reported averages

 

Table A3. Mean elevation and actual evapotranspiration (AET) for areas with and without historical inventory data inside the study area boundary (see Fig. 1). To allow for comparison, means were computed for entire quarter-quarter sections (QQs), as opposed to the estimated transects surveyed as in Table A1. Note that there are two less QQs than there were transects analyzed (n = 294). This is due to fact that the 1911 inventory transects on two of the QQs were broken into two separate observations (individual datasheets).

Variable

With historical data

Without historical data

Number of QQs

292

722

Elevation (m)

1393*

1481

AET (mm)

423

417

*denotes statistically significant means based on randomization tests (see Methods)

 

FigA1

Fig. A1. Proportion of historical inventory transects by large tree (>61 cm dbh) density class. Low basal area (BA) vegetation groups, as identified by our cluster analysis, are separated from all other forested transects.


 

Literature cited

Dixon, G. E. 2002. Essential FVS: a user's guide to the Forest Vegetation Simulator. Internal Report. Fort Collins, Colorado, USA 209 p.


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