Figure 1.— Stands used to investigate the 

 growth response of western redcedar to 

 release from competition. 



percentage of tree height), and descriptions of any 

 visible damage or injury. From each tree on the 

 variable-radius plots, one increment core to the tree 

 center was extracted at breast height (b.h.) from the 

 side facing the plot center. On each fixed-area plot, the 

 proportion covered by crowns of each shrub species 

 was estimated to the nearest 10 percent and the 

 heights of shrubs were measured to the nearest 1 foot 

 (30.5 cm). Using an occular system developed by 

 Wellner (1979), the percentage of sunlight striking the 

 forest floor was estimated within each stand. 



DATA PREPARATION 



The 15 stands had a wide variety of characteristics. 

 Mean stand diameters were small, ranging from 0.8 

 inches (2.0 cm) to 3.0 inches (7.6 cm), and densities 

 varied from 1.296 to 49,289 trees per acre (3,202 to 

 121.796 per ha) (table 1). The smallest and largest 

 mean stand d.b.h. - s for the 601 growth-sample trees 

 measured on the variable-radius plots, were 6.5 inches 

 (16.5 cm) and 31.8 inches (80.8 cm), respectively 

 (table 2). 



Thirty variables, both observed and derived, for the 

 601 growth-sample trees were included in the data as 

 follows: 



1. Stand location — geographic location on USGS 

 quadrangle maps 



2. Habitat type — (Daubenmire and Daubenmire 

 1968) 



3. Stand elevation — 100's of feet measured by an 

 altimeter 



4. Slope configuration — ridge top. upper slope, mid- 

 slope, lower slope, valley bottom 



5. Aspect azimuth — degrees 



6. Slope angle — percent 



7. Year of release — date 



8. Shrub height by species — feet 



9. Shrub cover by species — percent of forest floor 

 covered by shrub crowns on 1/300-acre (0.0013-ha) plot 



10. Sunlight striking forest floor — percent (Wellner 

 1979) 



11. Tree species — (Little 1979) 



12. Tree diameter at breast height — nearest 0.1 

 inch using diameter tape 



13. Tree height — nearest 1.0 foot, using clinometer 



14. Crown ratio — percentage of tree height in live 

 crown 



15. Crown class — (Smith 1962) 



16. Description of damage or injury to the tree 



17. Tree age at breast height based on count of 

 annual growth rings 



18. Annual tree ring widths — millimeters 



19. Diameter inside bark for various growth periods 

 computed from annual growth ring measurements 

 (d.i.b.) 



20. Basal area percentile — position of tree in stand 

 basal area distribution (BAP) 



21. Basal area of larger trees computed from tree list 

 (BAL) 



22. Stand crown competition factor (CCF) (Krajicek 

 and others 1961) 



23. Stand trees per acre (TP A) 



24. Stand basal area (BA) per acre 



25. Cluster crown competition factor (CCF) 



26. Cluster trees per acre (TP A) 



27. Cluster basal area per acre (BA) 



28. Point crown competition factor (CCF) 



29. Point trees per acre (TPA) 



30. Point basal area per acre (BA) 



In addition to those observed in the field, the following 

 data were derived for each point, cluster, and stand: 

 trees per acre (TPA), basal area per acre (BA), and 

 crown competition factor (CCF) (Krajicek and others 

 1961). The basal area percentile (BAP) for each tree was 

 computed: the position of the tree in the basal area dis- 

 tribution of the stand. Also for each tree in a stand, the 

 basal area of trees larger than the subject tree (BAL) 

 was computed. 



The growth-sample trees also provided growth infor- 

 mation and age for any period during the life of the 

 tree. The width of each annual ring in the increment 

 cores was measured with the aid of an electronic mea- 

 suring device (Graham 1980a). Diameter inside bark 

 (d.i.b.) was computed for 5 years before a release treat- 

 ment and for 5, 10. and 15 years after treatment, and 

 for the years 1975 and 1979. 



3 



