Table 3— Bioassay study: analysis of variance on first-year average height (mm) of the three 

 tallest seedlings for each species, treatment, and soil depth. Each figure is the 

 average of five replicates. Each replicate is represented by the average height of the 

 three tallest seedlings if available; otherwise two or one seedling. Within species and 

 column, means followed by different letters are significantly different at the 5 percent 

 level using Duncan's multiple range test 



Soil depth, cm 



Species Treatment 0-5 13-18 28-33 43-48 60-90 Mixed 



Average height, mm 



Huckleberry 



Bracken 



3.0" 



3.4= 



4.9= 



3.9= 



3.1 = 



3.3=' 





Sprayed 



2.3" 



2.5= 



4.5= 



3.6= 



3.2= 



2.5" 





Forested 



6.4= 



4.3= 



4.6= 



4.1 = 



4.3= 



7.1 = 



Alder 



Bracken 



11.5" 



12.7=" 



9.2= 



6.5" 



6.8= 



7.6" 





Sprayed 



10.5" 



6.7" 



8.0= 



4.5" 



6.1 = 



6.8" 





Forested 



23.8= 



18.3= 



13.8= 



11.1 = 



8.2= 



15.4= 



Subalpine fir 



Bracken 



14.9= 



15.1 = 



13.7= 



13.5= 



11.1 = 



12.9= 





Sprayed 



15.6= 



13.9= 



15.5= 



14.3= 



13.9= 



15.3= 





Forested 



15.7= 



13.7= 



13.5= 



12.9= 



11.6= 



13.7= 



Engelmann spruce 



Bracken 



13.9" 



14.0= 



13.3= 



12.7= 



11.2= 



12.9= 





Sprayed 



15.4=" 



14.8= 



13.0= 



13.3= 



11.2= 



14.2= 





Forested 



17.5= 



14.1 = 



12.6= 



11.3" 



11.5= 



13.5= 



Douglas-fir 



Bracken 



31.5= 



31.4= 



28.8= 



27.5= 



21.9" 



30.2= 





Sprayed 



30.1 = 



32.0= 



31.9= 



27.4= 



25.0=" 



32.4= 





Forested 



33.8= 



29.1 = 



28.5= 



27.7= 



28.5= 



30.1 = 



Grand fir 



Bracken 



27.7= 



29.6= 



26.3= 



26.3= 



24.9= 



28.3= 





Sprayed 



29.1 = 



27.3= 



27.8= 



28.3= 



26.2= 



29.6= 





Forested 



27.7= 



30.0= 



29.6= 



29.9= 



27.9= 



30.7= 



the side of the pan extending about 2 cm above ground 

 level. A hole on the bottom, downhill side of each pan pro- 

 vided drainage. The purpose of the potting mix was to 

 separate the effects of the current year's litter from the 

 effects of the native soil. 



Nylon mesh seed packets were prepared to enable 

 recovery of seed after stratification. Packets were 15 cm^ 

 and sewn into quarters to hold 25 seeds of each species. 

 Packets were labeled, enclosed with wire screening to 

 prevent rodent feeding, and placed at the study site on 

 October 4 and 5, 1984. In October, the bracken fronds 

 were brown but standing, and the wet season had not 

 begun. 



Six replications of seed packets were placed in each 

 treatment area. Packets placed on native treatment soil 

 were tet"hered by a wire to a stake driven into the ground. 

 Loose litter was brushed away to ensure seed packets 

 were in contact with the soil surface. Small wires pinned 

 seed packets to the ground. 



Six replications of seed packets in potting mix soil were 

 placed in an aluminum pan. Litter removed when burying 

 the pans was replaced on top of the packets. Then stand- 

 ing fronds in bracken treatments were bent over the pans 

 and covered with hardware cloth to hold the litter and 

 seed packets in place. 



Seed was overwintered at the site and collected on 

 June 5, 1985. Although the study site was free of snow 

 before June 5, earlier access was prevented by snowdrifts 

 in the roads. Soil and seed packets were transported to 



Moscow and stored in a cooler at 2 °C while seeds were 

 examined and transferred to germination trays. 



As an additional check on seed viability, six replications 

 of seed for the four conifer species were placed in ger- 

 mination trays. Seed was stratified for 10 minutes in a 

 solution containing 60 percent distilled water and 40 per- 

 cent bleach (the bleach contained 5.25 percent sodium 

 hypochlorite), then rinsed for 65 hours in running water— a 

 procedure recommended by Advincula and others (1983). 

 Each germination tray held 25 seeds of one species, the 

 seeds being placed on filter paper and moistened with 

 distilled water. These trays, and those containing seed 

 stratified at the study site, were kept in growth chambers 

 at 30 °C and 8 hours of light alternated with 20 °C and 

 16 hours of darkness. 



Results 



Much of the conifer seed germinated at the study site, 

 and radicles had penetrated the nylon mesh and wire 

 screen. Ungerminated seed was transferred to germination 

 trays, but few of these seeds germinated. Molds eventually 

 became a problem, and moldy seed was discarded to pre- 

 vent contamination of other seed. 



Results of seed germination are summarized in table 4. 

 First, total percentage of germination is shown by species, 

 treatment, and soil type. This figure includes all seed that 

 germinated (radicle length ^ seed length). Next is shown 

 the percentage of seed that had germinated but was dead 



7 



