ABSTRACTS

Campana, R.J. 1976. Air pollution effects on urban trees. Trees Magazine 35(2): 35-38.

What are the principal air pollutants that are toxic to plants? What is their origin? How do they affect plants? How serious are they at present? What significance do they have for survival of the trees involved and what can be done to decrease or minimize damage from those of primary concern. The discussion here will include consideration of: the role of trees in the urban environment; the nature of air pollutants; comparative evaluation of damaging pollutants; comparative susceptibility of trees tested; the combined influence of air pollutants with other stress factors; compensatory aspects of air pollution; recommendations to reduce adverse impact from air pollution; and the significance of the problem for the future of urban tree management.

Mullin, R.E. and J.P. Parker. 1976. Provisional guidelines for fall lifting for frozen overwinter storage of nursery stock. Forestry Chronicle 52(1): 104.

Overwinter storage of nursery stock has many advantages to offer the nurseryman and tree planter. In recent years there has been (in northern climates) a shift from cold storage (above freezing temperatures) to frozen storage. However, frozen storage losses have occurred, and may be due to improper timing of the fall lift for storage. An experiment was started in the fall of 1972 to study the effects of the date of fall lifting on the post-planting performance of overwinter-stored white spruce and jack pine. Storage at two temperatures was used, 0 deg. F and 26 deg. F, with the former a failure, the latter successful. Spring planting indicated that “too early” outplanting is possible. Stored white spruce may be used to extend the planting season into late spring, but not jack pine.

Sterner, T.E., W.R. Newell, and F.A. Titus. 1976. European elm bark beetle in New Brunswick—a new record. Bi-Monthly Research Notes 32(3): 15.

Dutch elm disease was first found in the Maritime Provinces of Canada in 1957. The causal fungus, Ceratocystis ulmi has since spread, until in 1975 the disease is known to occur in 12 of 15 counties in New Brunswick and in 7 of 18 counties in Nova Scotia. The disease has not yet been found in Prince Edward Island. The chief vector of this disease is Hylurgopinus rufipes (Eichh.), the native elm bark beetle. Scolytus multistriatus (Marsh.), the European elm bark beetle, considered a primary vector in most of the United States, has not previously been trapped in the Maritimes Region. A single specimen of S. multistriatus was trapped at Upper Mills, Charlotte County, between June 23 and July 23, and is the first record of the European elm bark beetle trapped in the Maritime Provinces. Examination in October of about 50 elms within a 1 -km radius of the trap did not reveal any galleries typical of S. multistriatus, indicating that the population of the European elm bark beetle is extremely low in the area surveyed.