Editing Tree planting (section)

===Spring and summer planting with stored stock===
Refrigerated storage of planting stock has been developed largely with the aim of overcoming problems experienced in using flushed planting stock. Storage provides a means of holding stock for use when fresh stock is either unavailable or at a stage of development that renders it unsuitable for planting. It also offers possibilities of manipulating the physiological condition of the stock. However, there are problems associated with storage, e.g., mold, cold injury, desiccation, and depletion of food reserves. The rate of deterioration depends very much on the physiological condition of the planting stock at the time of lifting, as well as on the storage environment and duration of storage.<ref name="mull5">Mullin, R.E. 1978. "Tests of frozen spring storage for white spruce and red pine planting stock." USDA, For. Serv., Tree Plant. Notes 29(4):26–29.</ref>

Mullin and Forcier (1976)<ref name="mull6">Mullin, R.E.; Forcier, L. 1976. Effect of lifting and planting dates on survival and growth of spring stored nursery stock. Ont. Min, Nat. Resour., For. Res. Branch, Toronto ON, For. Res. Notes 3. 4 p.</ref> and Mullin and Reffle (1980)<ref name="mull8">Mullin, R.E.; Reffle, R.J. 1980. Effects of dates of lifting and planting on success of frozen spring storage at Swastika Nursery. Ont. Min, Nat. Resour., Toronto ON, Nursery Notes 66. 5 p.</ref> examined the effects of spring-lifting date and planting date on several species, including 3+0 white spruce after frozen storage, with fresh-lifted controls planted on each planting date for comparison. In all plantings, the earliest (2 May) lifting gave highest average second-year survival in all species. In another study, Mullin (1978)<ref name="mull5" /> found that outplantings of frozen-stored 3+0 white spruce were consistently successful to the end of July only with the earliest-lifted (25 April) stock. Sutton (1982)<ref name="Sutton 1982">Sutton, R.F. 1982. "Plantation establishment in the boreal forest: planting [[season extension]]." Can. Dep. Environ., Can. For. Serv., Sault Ste. Marie ON, Inf. Rep. O-X-344. 129 p.</ref> also used 3+0 white spruce in outplanting every 2 weeks from the end of June through the growing season in 3 successive years on a variety of sites in northern Ontario. Despite variation in planting stock, poor storage environments and adverse weather, 4th-year results showed a consistent pattern of reasonable survival and growth rates among trees planted through July, with a rapid decline in performance of trees planted thereafter. Overwinter storage of stock has also been employed. It has the advantage of lifting stock at the end of the growing season when physiological processes are invoking natural dormancy.<ref name="mull7">Mullin, R.E.; Parker, J.D. 1976. "Provisional guidelines for fall lifting for frozen overwinter storage of nursery stock." For. Chron. 52(1):22–25.</ref>

Natural refrigerated overwinter storage has been used in root cellars and snow caches. Using natural refrigeration in root cellar storage, Jorgensen and Stanek (1962)<ref name="jorg">Jorgensen, E.; Stanek, W.K.L. 1962. "Overwinter storage of coniferous seedlings as a means of preventing late frost damage." For. Chron. 38(2):192–202.</ref> kept 3+0 and 2+2 white spruce in dormant condition for 6 months without apparent detriment to performance after outplanting. Moreover, the stock was highly resistant to spring frost damage. Natural cold storage for overwintering 3+0 and 2+2 white spruce was also used by Mullin (1966).<ref name="mull1">Mullin, R.E. 1966. "Overwinter storage of baled nursery stock in northern Ontario." Commonw. For. Rev. 45(3):224–230.</ref> Unlike Jorgensen and Stanek's (1962)<ref name="jorg" /> stock, which was raised 550&nbsp;km to the south of where it was planted, Mullin's stock was raised in a nursery at about the same latitude as the planting site; the stock experienced inside-bale temperatures down to -15&nbsp;°C in mid-winter, but still showed first- and second-year survival rates of 85.9% and 65.9%, respectively, compared with 91.4% and 76.2%, respectively, for fresh-lifted stock. However, Mullin's stored stock was much more damaged by spring frost than was fresh-lifted stock and it "showed a reduction in vigour as measured in terms of survival, susceptibility to damage and growth".