Table 4.— Analysis of variance table, lodgepole pine, 1972 study 



Discussion 



Source 



DF 



MS 



F 



Prob. < F 



Blocks 



2 



0.0375 



2.7535** 



0.066 



Storage 



3 



.2190 



16.0772** 



.0001 



Date 



4 



2.5211 



185.0968* * 



.0001 



Stress 



2 



.0380 



2.7920 



.0636 



Storage X date 



12 



.5275 



38.7251 * * 



0001 



Storage X stress 



6 



.0509 



3.7343** 



.0023 



Date X stress 



8 



.0061 



.4500 



.8886 



Storage X date X stress 



24 



.0169 



1.2417 



.2214 



Error 



118 



.0136 







* 'Significant at the 99 percent level of confidence. 



WESTERN LARCH 



All three main variables (storage, stress, and planting date) 

 had highly significant influences on larch survival in the analysis 

 of variance (table 5). Storage-date interaction was also highly sig- 

 nificant; stress-date interaction was significant. Increasing stress 

 caused a significant decline in the survival of western larch as it 

 did with Engelmann spruce (fig. 4). At the low stress level 

 (fig. 4a) survival generally declined when trees were planted later 

 than the second planting (April 25) regardless of storage. Frozen 

 stock survived exceptionally well (above 80 percent) even when 

 planted as late as June 27. Survival of freshly lifted stock de- 

 clined when planted after April 25 and reached a low of 30 per- 

 cent survival at the fourth (June 6) planting, but regained its po- 

 tential when lifted and planted on June 27. Snow cache and 

 regularly stored stock survived well when planted through June 6 

 but failed when held until June 27 for planting. 



Moderate stress reduced overall survival and, as with spruce, 

 resulted in an expression of storage deterioration at an earlier 

 planting date than at low stress levels (fig. 4b). Survival under 

 moderate stress declined to unacceptable levels (30 to 50 percent) 

 by the third planting (May 16). Survival increased from the 

 fourth to the fifth planting with freshly lifted stock. Both fresh 

 and frozen stock survived significantly better than regular or 

 snow cache stock from the last planting. 



Under extreme stress the same pattern prevailed but at a lower 

 overall survival rate (29 percent) and with less overall variability 

 in survival rates (fig. 4c). 



Table 5.— Analysis of variance table, western larch, 1972 study 



Source 



DF 



MS 



F 



Prob. < F 



Blocks 



2 



0.1956 



5.6845** 



0.0047 



Storage 



3 



.5000 



14.5315** 



.0001 



Date 



4 



2.2613 



65.7300** 



.0001 



Stress 



2 



5.2465 



152.5015** 



.0001 



Storage X date 



12 



.4905 



14.2583** 



.0001 



Storage X stress 



6 



.0330 



.9588 



.5427 



Date X stress 



8 



.0773 



2.2484* 



.0282 



Storage X date X stress 



24 



.0404 



1.1749 



.2787 



Error 



118 



.0344 







'Significant at the 95 percent level of confidence. 

 "Significant at the 99 percent level of confidence. 



Interpretation of these results should be tempered by the reali- 

 zation that there is a possible confounding of stress and planting 

 date. It was obvious by mid-July that the weed growth in areas 

 planted in April and mid-May was more abundant and luxurious 

 than in areas planted in June. Soil moisture monitoring was not 

 adequate to verify any differences in soil moisture depletion asso- 

 ciated with planting date. Nevertheless, we cannot imagine that 

 depletion rates during the stressing period did not vary by plant- 

 ing date. It is also possible that there could have been inadvertent 

 stressing of trees prior to July 1 when the planned stress cycles 

 started. Due to weed differences associated with planting dates, 

 this stressing could have varied with the planting date. Such a 

 variation may account for the tendency in all species for survival 

 to be less from the first planting than from the second planting 

 under moderate and severe stress levels. 



If the observed greater weed growth in the early plantings ap- 

 plied more stress to seedlings planted early and less to seedlings 

 planted later, the effect of planting date on survival as reported 

 in our data may be a conservative estimate. This confounding 

 would affect the magnitude but not the direction of the observed 

 effects. 



The performance of the freshly lifted and planted stock was 

 the most surprising result of this study. Fresh spruce and lodge- 

 pole pine stock survived as well as, or better than, all other stock 

 at each planting date and stress level. Fresh larch stock survived 

 poorly compared to stored stocks for the May 16 and June 6 

 plantings, but had the best average survival rate in the June 27 

 planting. Whether survival of freshly lifted stock under the con- 

 ditions imposed in this study has any practical application could 

 only be determined by further study. This type of "hot plant- 

 ing" may have limited utility. In this study the maximum time 

 between lifting and planting was 1 day, hardly typical of the 

 usual planting operation. Should longer periods of field storage 

 have a different effect on the various stocks studied, the results 

 of typical operational field plantings with "fresh" stock could be 

 much different from the results of this study. 



Lest the temperature of the frozen stock be considered the 

 cause of its performance, it should be pointed out that the time 

 at which the frozen stock was lifted may be as important or more 

 important than the storage temperature. Stock for this treatment 

 was lifted in a state of rest or deep dormancy before its chilling 

 requirements had been satisfied (Romberger 1963). The relative 

 importance of temperature and state of dormancy needs more 

 clarification. The low incidence of abnormal terminal buds and 

 shoots in frozen spruce stock suggests that: (1) bud chilling re- 

 quirements are not being satisfied with normal overwinter nurs- 

 ery field climate, lifting, and storage regimes, or (2) spring lifting 

 and storage procedures upset the normal pattern of activity and 

 growth. 



5 



