IntensIve sIlvIculture - Forest Science Labs - Research Network ...

Keywords: nursery operations
growth
Abstract: Douglas fir (Pseudotsuga menziesii) seedlings of a single (Vancouver Island)
seed source were grown in a nursery on Vancouver Island, British Columbia, Canada, for two
years to produce five different bare rooted stock types through varying spacing and transplanting
treatments: spacing of 1.2, 7.7 and 14.3 cm; 14 cm 1+1 transplant; and 14 cm container
transplant. They were then planted in the forest together with one-year-old container seedlings of
the same seed source (a sixth treatment). Stem volume mean relative growth rate (Rv) was low
immediately after planting for all stock types except the container seedlings, and increased over
the following 7.6 years. An 8-week greenhouse test of the six stock types showed that dry weight
mean relative growth rate (Rw) generally decreased with seedling dry weight, but this effect was
less obvious after planting because only the three smaller stock types showed a decrease in Rw
with size. In another experiment, bare root Douglas fir seedlings were grown at five different
spacings (1.9, 2.8, 5.0, 7.4 and 10.6 cm) in a nursery for two years, and seedlings from each
spacing treatment were sorted into 'large' or 'small' by height. Resulting 10 treatments were
outplanted and stem volumes determined over 6.7 years. Effect of nursery spacing on stem
volume was linear up to 3.6 years after planting, but large seedlings had greater stem volume than
small seedlings throughout the 6.7 years of the study. There was no indication that Rv decreased
with time, but small seedlings had a greater Rv than large seedlings. Relative growth rates of 2year-old
Douglas fir were depressed for a year or two after planting, but then remained relatively
constant, or increased during the ensuing 5 years. Relative growth rates of smaller seedlings were
greater than those of larger seedlings so that relative biomass differences decreased with time,
and the time advantage of larger stock decreased. Absolute size differences increased with time.
154. Driessche, R.v.-d. 1992b. Changes in drought resistance and root growth capacity of container
seedlings in response to nursery drought, nitrogen, and potassium treatments. Canadian-Journalof-Forest-Research.
Keywords: nursery operations
nursery fertilization
tree/stand protection
tree/stand health
growth
carbon allocation
tree physiology
Abstract: Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), and white
spruce (Picea glauca) seedlings, each represented by two seed lots, were grown in Styroblock
containers in a greenhouse and plastic shelter house from February 1989 to January 1990. The
seedlings were exposed to two N treatments (20 and 200 mg/litre) and three K treatments (5, 25
and 100 mg/litre) arranged factorially within three drought treatments. After winter storage,
seedlings from a complete set of treatments were planted into hygric, mesic and xeric sand beds
during 12-14 March. Increasing nursery drought stress increased survival of Douglas fir and
lodgepole pine after planting, and high N treatment level increased survival of lodgepole pine and
white spruce. Under xeric conditions, combined nursery drought and high N treatments increased
survival of lodgepole pine by 33%, indicating the importance of nursery cultural regime for stock
quality. Increase in nursery drought stress did not decrease seedling size by much; increase in N
increased seedling size one season after planting. A positive relation between shoot : root ratio
and survival in lodgepole pine and white spruce indicated that increase in N increased both shoot
growth and drought resistance over the N range investigated. Only Douglas fir showed an
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