Author: J. R. Parmeter
Publisher:
Published: 1989
Total Pages: 6
ISBN-13:
DOWNLOAD EBOOK →Spread and buildup of dwarf mistletoe, Arceuthobiun abietinum, was studied on inoculated white fir, Abies concolor, and red fir, A. magnifica, in northern Califomia for 23 to 28 years. At the end of these studies (1986), and in the absence of overstory infection, 13 of 23 trees had dwarf mistletoe populations that were the same or smaller than the original populations resulting from inoculation. Mortality of infections was the main factor limiting population increases. Live crown ratio of all trees averaged over 0.8. The average ratio of tree height growth to vertical spread rate of dwarf mistletoe was 11.5 to 1 in white fir and 7 to 1 in red fir in the Sierra Nevada. In the southem Cascades, the average ratio was 1.7 to 1 in red fir. About one fourth of the trees became infected in the bole. Of 14 additional trees infected by lateral spread of the parasite, 13 were within 6 m of the source of infection. Evidence continues to indicate that losses from dwarf mistletoes will be small in well-managed young fir stands free from infected overstory trees and properly spaced to promote good growth.
Author: Robert F. Scharpf
Publisher:
Published: 1977
Total Pages: 4
ISBN-13:
DOWNLOAD EBOOK →Dwarf mistletoe had no noticeable effect on trunk taper of young, dominant and codominant red firs 4 to 22 inches (10.2 to 55.9 cm) d.b.h. Also, taper was not influenced by live crown ratio of infected and uninfected trees. Trees less than 7 inches d.b.h. had significantly more taper than larger trees, irrespective of dwarf mistletoe.
Author: Robert F. Scharpf
Publisher:
Published: 1976
Total Pages: 16
ISBN-13:
DOWNLOAD EBOOK →Rate of population buildup of dwarf mistletoe, Arceuthobium abietinum Engelm. ex Munz., was slow in most small red firs and white firs 12 to 15 years after inoculation with the parasite. Where population buildup did occur, it remained clustered in the lower portions of tree crowns near inoculation sites. Maximum distance of vertical spread was 16 feet (4.8 m), after 15 years. The mean annual rate of vertical spread of the parasite in 12 to 15 years was 3 inches (7 cm) or less in test trees. No vertical spread occurred in some trees. Rate of vertical spread was much slower in all trees than the mean annual height growth of vigorous young red or white firs. Therefore, the test trees were outgrowing the spread of dwarf mistletoe within tree crowns. Vertical spread rate and rate of tree height growth together determine the proportion of tree crown that will be infested at a given time after inoculation.
Author: Robert F. Scharpf
Publisher:
Published: 1982
Total Pages: 16
ISBN-13:
DOWNLOAD EBOOK →Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches resulted in infections. Second-generation infections developed and populations of the parasite built up on some trees but not on others after 17 years. Variables that appeared to regulate population increases included an 8- to 9-year average between inoculation and fruiting of plants, low rate of fruit production among female plants, low proportion of plants producing abundant fruit (100 or more/year), and irregular production of fruit on plants over the years, Death of infected branches also helped keep populations of the parasite in check. In vigorous, well-managed stands of young firs, dwarf mistletoe populations may not build up rapidly enough to result in serious losses.