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

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in an emitted spray volume of 11.3 litres/ha; 5-8 weeks after spraying, 77-100% of live larvae
were infected. Two plots were treated from the ground at 2.4 x 1010 PIB in 4.5 litres/tree; 8
weeks after treatment 83-85% of live larvae were infected. No egg-masses could be found in the
treated plots in the autumn of 1981, and no larvae were found on sample trees in 1982 or 1983.
The treatment was effective over a range of initial mean larval densities of 41-206/msuperscript 2
foliage. Populations in untreated areas nearby increased in 1982. Little foliage protection was
obtained the year of application, due to the lengthy virus incubation period, but the trees
recovered quickly when larval populations disappeared.
553. Shumway, J.S. and H.N. Chappell. 1995. Preliminary DRIS norms for coastal Douglas-fir soils in
Washington and Oregon. Canadian-Journal-of-Forest-Research 25(2): 208-214.
Keywords: fertilization
thinning
growth
soil properties
Abstract: The Diagnosis and Recommendation Integrated System (DRIS) has been used
successfully to evaluate interactions between nutrients and fertilizer response and for diagnosing
nutrient deficiency in agricultural crops. This study used soil tests to develop DRIS norms and
evaluate their effectiveness in coastal Douglas fir (Pseudotsuga menziesii) forests. DRIS norms
for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index
data from 72 soil series that commonly support Douglas fir in western Washington. The norms
were tested using soil test and stand basal area growth response data from 20 thinned and 30
unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in
thinned stands averaged 34% and 43% for 224 and 448 kg N.ha-1, respectively, when N was
identified as the most limiting nutrient. When N was not the most limiting nutrient, N response
averaged 8% and 10% for 224 and 448 kg N.ha-1, respectively. Results were similar in unthinned
stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned
stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%)
where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%)
sites that responded by less than 15% were correctly identified by DRIS. The results clearly
indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients
at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide
an assessment of these interactions.
554. Simpson, D.G. 1984. Filmforming antitranspirants: their effects on root growth capacity,
storability, moisture stress avoidance, and field performance of containerized conifer seedlings.
Forestry-Chronicle 60(6): 335-339.
Keywords: nursery operations
tree physiology
growth
tree/stand health
Abstract: One of 6 antitranspirants was sprayed on Pinus contorta, Picea glauca, Tsuga
heterophylla and Pseudotsuga menziesii seedlings before or after a 12-wk storage period at 2
degrees C. Root growth capacity and pre-dawn water potential were measured immediately after
treatment or after storage. Sample seedlings were planted out in British Columbia in April and
May 1981 and survival and growth recorded after one season (Sept.). XEF-4-3561-A, Wilt Pruf,
Folicote and Vapor Gard increased moisture stress avoidance (water potential) in all species.