3. Snow cached.— On March 18, 1972, 1,125 trees of each 

 species were lifted, packaged, and stored as described in 2 above. 

 Five days later these seedlings were placed in a snow cache near 

 Coeur d'Alene at an elevation of 4,800 ft (1 463 m). The cache 

 was constructed according to methods described by Dahlgren 

 and others (1974). At each subsequent planting date the cache 

 was opened, stock removed, and the cache resealed. The cache 

 was still usable in late July, long after the last stock had been 

 removed. 



4. Fresh. — Seedlings were freshly lifted just prior to each 

 planting, refrigerated at 34° to 36° F (1° to 2° C) overnight, 

 and planted the next day. 



Stock survival after planting was tested using the Variable- 

 Moisture-Stress-Plot Technique described by Boyd and others 

 (1972). Trees were planted on five dates: April 4, April 25, 

 May 16, June 6, and June 27, 1972 (table 1). On each date, three 

 25-tree bundles of each species from each storage treatment were 

 planted in each of three moisture stress plots, as follows: 



Table 1.— Length of nursery stock storage prior to planting, 

 1971-72 



Length of storage 



Planting date 



Snow cached 



Refrigerated 



Frozen 



April 4 

 April 25 

 May 16 

 June 6 

 June 27 



13 

 34 

 55 

 78 

 97 



Days 



18 

 39 

 60 

 81 

 102 



139 

 159 

 180 

 201 

 222 



1. Low stress. — Soil moisture was maintained above 30 per- 

 cent of Field capacity by irrigation and periodic removal of weed 



competition. 



2. Moderate stress. — Soil moisture was allowed to deplete to 

 natural levels. Weed competition was periodically removed. 

 Plots were not irrigated. 



3. Extreme stress. — Soil moisture was allowed to deplete to 

 natural levels. Weed competition was undisturbed. Plots were 

 not irrigated. 



Seedlings were planted 12 inches (30.48 cm) apart, within 

 plowed furrows 18 inches (45.72 cm) apart. Transplanting 

 boards were used to facilitate planting. Soil moisture in the plots 

 was monitored during the summer to aid in timing of irrigation 



and weeding. 



Until all five plantings were completed, soil moisture in all the 

 stress plots was kept at or above 50 percent availability by a tem- 

 porary watering system. After July 1, the moderate and extreme 

 stress plots were not watered. Low and moderate stress plots 

 were weeded every 4 weeks. The low stress plot was irrigated five 

 times and each watering lasted an average of 6 hours. An average 

 of 0.96 inches (2.45 cm) of water was applied at each watering. 

 Distribution of rainfall during the planting and stress period is 

 shown in figure 1. 



Survival tallies were made on August 1 , September 2, and 

 October 5, 1972. Analysis of variance for a factorial design was 

 applied to the October 5 data of each species with tests for sur- 

 vival differences attributable to storage, planting date, stress 

 level, and possible interactions among these main variables. Sur- 

 vival percentages were transformed to the arc sin Vpercent for 

 analysis. 



i.o r 

 I °- 



I 0.6 - 

 i 0.4 

 2. 0.2 



i "ij, * i 



t Apr. \ 

 Total ppl. ■ 2.32" 



May t 



2.33" 



t June 

 1.61" 



July 

 0.67" 



Aug. 

 1.64" 



Sept. 

 1.21" 



Figure 1. — Growing season precipitation, 1972, 

 Coeur d'Alene, Idaho. 



Results 



ENGELMANN SPRUCE 



Figure 2 depicts the survival of spruce under all of the test con- 

 ditions. With increasing stress, the average survival declined 

 from 90 percent under low stress to 54 percent at moderate stress 

 and finally to 39 percent under the severe moisture stress regime, 

 indicating a good range of test conditions. Differences were 

 highly significant (table 2). 



Under low stress conditions (fig. 2a) stock storage regimes had 

 no significant influence on survival for the first four planting 

 dates. However, survival of the stock planted on June 27 was 

 greatly influenced by storage treatment. Survival of spring-lifted 

 stock stored in both snow cache and regular nursery storage was 

 much lower for the June 27 planting. 



Moderate stress (fig. 2b) produced a similar but less uniform 

 pattern with significant survival differences attributable to stor- 

 age evident in both the fourth and the fifth plantings. This pat- 

 tern indicates that stock deterioration in storage and greater 

 planting site stresses reduced survival. 



Under extreme moisture stress (fig. 2c), the survival of spruce 

 stock became quite erratic, but the trends established under low 

 and moderate stress were still evident. Much of the variation in 

 survival at the extreme stress level may have been caused by the 

 inability to create a uniformly severe soil moisture stress due to 

 chance soil moisture and weed competition variations. 



Of particular interest was the performance of freshly lifted and 

 planted spruce stock. Lifting and planting during late May and 

 early June caused significantly lower survival rates than either 

 earlier plantings or.the final planting of June 27. This period of 

 poor survival coincides with the period of rapid shoot elongation 

 in the nursery. By June 27 elongation had probably slowed con- 

 siderably and succulent new tissue had probably started to 

 harden. Unfortunately, no data are available to test this 

 hypothesis. 



In mid-July some outstanding differences in spruce bud burst- 

 ing and subsequent growth were noticed and data on bud and 

 shoot abnormalities were gathered. For each treatment unit a 

 count was made of abnormal terminal shoots and/or buds, and 

 expressed as a percentage of the unit population. Since the buds 

 of the trees from the last planting (June 27) were just beginning 

 to break, they were not considered in this examination. Stock 

 lifted in the spring and planted shortly afterward had by far the 

 greatest number of abnormal terminal buds and shoots (27 per- 

 cent) (table 3). Seedlings lifted in the spring and stored in refrig- 

 erators or a snow cache were intermediate in frequency of ab- 

 normal terminals (8 to 10 percent). The least abnormality oc- 

 curred in seedlings lifted in November and held at 28° F (-2° C) 

 until planted (2 + percent). 



2 



