Physiological processes for juvenile and adult foliage of Juniperusoccidentalis Hook. were compared to evaluate the advantages and disadvantages of juvenile foliage for a stress-tolerant, invasive conifer. Above- and below-ground biomass allocation and monthly measurements (April through October) of gas exchange, water relations, foliar nitrogen concentrations, and growth were made for juvenile and small-adult trees in the field in central Oregon. Compared with small adults, juveniles have greater allocations to foliage and fine-root biomass, higher rates of CO2 assimilation, leaf conductance, and transpiration, and lower investments of biomass and nitrogen per unit of foliar area. Juvenile foliage is less costly to produce than adult foliage. The suite of physiological processes associated with juvenile awl-like foliage should enhance establishment and early growth of J. occidentalis. However, high rates of water loss, which are associated with high rates of CO2 assimilation of juvenile foliage, appear to be a liability for large trees in the semiarid environment of eastern Oregon. Once established, the transition to a more conservative use of resources associated with adult scale-like foliage is consistent with the stress-tolerant strategy of long-lived evergreen trees.
A class of damage which has been termed " blighted cones " occurs frequently in the seed crops of sugar pine throughout its range in California and Oregon and of western yellow pine in the Pacific coast and southern Rocky Mountain regions. This damage is distinguished by the dying of the immature cones soon after the starting of the second year's growth. The dead blighted cones, which are less than one-half the size of normal cones, are withered and faded to a reddish brown. The blighted sugar-pine cones fall to the ground during the first summer, whereas the blighted yellow-pine cones may adhere to the branches for several }^ears. INSECTS CAUSING DAMAGE. The greater part of this damage 1 is caused by small scolytid beetles, which have been identified by Dr. A. D. Hopkins, of the Bureau of Entomology, as Conophthorus spp. The common name of " cone beetles " seems most appropriate for these insects, as their life history and the damage caused by them relate entirely to the cones of the host trees. The adults are small, black, cylindrical beetles, from 3 to 4 mm. in length. The adult beetle bores a small tunnel through the axis of the cone, wherein the eggs are deposited. The larvae, tiny white grubs from 3.5 to 4.5 mm. in length when full grown, feed upon the scales, seeds, and tissues of the withering cone. The pupae, which differ but little in size and color from the larvae but possess the form of the adult, are formed within the same cone 1 The caterpillars of certain cone^moths also kill immature second-year yellow-pine cones, in such a way that the damage resembles the work of the cone beetle, but this damage may be readily recognized by the character of the attack. In the areas observed by the writer the cone worms cause less than 10 per cent of the blighted cones. Note.-This bulletin is the result of field observations made in Oregon and California. It is suitable for distribution on the Pacific coast.
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