HEMLOCK AND LARCH DWARF MISTLETOE SEED DISPERSAL

1966 ◽  
Vol 42 (4) ◽  
pp. 395-401 ◽  
Author(s):  
Richard B. Smith
Keyword(s):  
Seed Dispersal ◽  
Western Hemlock ◽  
Dwarf Mistletoe ◽  
Western Larch ◽  
Potential Sources ◽  
Tree Seeds ◽  
Larch Tree

During 1964-65, approximately 49,050 hemlock dwarf mistletoe seeds were dispersed from a severely infected 35-ft. western hemlock tree, and 3,750 larch mistletoe seeds were dispersed from a lightly infected 63-ft. western larch tree. Seeds were trapped over an area 5,800 ft.2 in extent around the hemlock, and over an area of 2,200 ft.2 around the larch.The peak of larch mistletoe seed dissemination was about 1 month earlier than for hemlock. Seed counts for both years and both mistletoes were highest in the southwest and least in the northeast quadrants of the trapping areas.It was firmly established that small trees, even if lightly infected, are a serious potential sources of dwarf mistletoe seed; they must be removed if satisfactory dwarf mistletoe control is to be achieved.

EcologyDevelopment of Dwarf Mistletoe (Arceuthobium) Infections on Western Hemlock, Shore Pine, and Western Larch

1971 ◽  
Vol 1 (1) ◽  
pp. 35-42 ◽  
Author(s):  
R. B. Smith
Keyword(s):  
Seed Dispersal ◽  
Life Span ◽  
Western Hemlock ◽  
First Year ◽  
Mature Fruit ◽  
Dwarf Mistletoe ◽  
Western Larch ◽  
The Third ◽  
Second Year ◽  
Shore Pine

Newly dispersed seeds, established infections, and individually tagged shoots of hemlock dwarf mistletoe on western hemlock and shore pine, and established infections and individual shoots of larch mistletoe on western larch were examined periodically for up to 7 years, Infections on hemlock first appeared as swellings, some of which were visible during the first year after seed dispersal. Aerial shoots appeared in the second year. By the end of the third year most infections exhibited both swellings and aerial shoots. On all three hosts, mature mistletoe fruit were produced occasionally in the fourth year but generally not until the fifth year. Most female aerial shoots bore at least one crop of flowers during their existence, however, only half produced mature fruit. Aerial shoots varied in their life span from less than 1 year up to 7 years. The average was 2 to 3 years. One female shoot on larch bore five successive crops of flowers. The fastest longitudinal growth of mistletoe endophytic system occurred on western larch and the slowest was on shore pine. All infections were nonsystemic in that the endophytic system was largely confined to the swollen portions of the hosts.

Overstory spread and intensification of hemlock dwarf mistletoe

1977 ◽  
Vol 7 (4) ◽  
pp. 632-640 ◽  
Author(s):  
R. B. Smith
Keyword(s):  
Seed Germination ◽  
Seed Dispersal ◽  
Western Hemlock ◽  
Dwarf Mistletoe ◽  
Dispersal Patterns ◽  
Early Autumn ◽  
Early Removal ◽  
Residual Tree ◽  
Early Damage

Development of dwarf mistletoe (Arceuthobiumtsugense (Rosendahl) G.N. Jones) on 51 western hemlock (Tsugaheterophylla (Raf.) Sarg.) trees planted in 1963 at varying distances from an infected residual tree is described. Distribution of infections in the planted trees related directly to seed-dispersal patterns, i.e., it was influenced mainly by distance and direction from the infected residual. Factors controlling the numbers of infections produced included the amount of throughfall and winter depredation of seed, germination, and infection success. From an initial dispersal of 100 seeds, an average of 37 attached firmly and were retained on the branches the next spring, 23 germinated, and 13 caused infection. The influence of early autumn frosts, death of established infections, and variation in resistance levels in the trees on the ultimate number of functioning infections is documented. It was concluded that with early removal of the overstory source, levels of infection sufficiently high to cause significant early damage on all intervening regeneration would result with about 86 evenly scattered, severely infected residuals per hectare.

Long-distance wind dispersal of tree seeds

1995 ◽  
Vol 73 (7) ◽  
pp. 1036-1045 ◽  
Author(s):  
D. F. Greene ◽  
E. A. Johnson
Keyword(s):  
Seed Dispersal ◽  
Conservation Biology ◽  
Plant Conservation ◽  
Dispersal Distance ◽  
Wind Dispersal ◽  
Source Strength ◽  
Long Distance ◽  
Model Predictions ◽  
Tree Seeds ◽  
The Relationship

Long-distance seed dispersal figures prominently in most plant conservation biology arguments, yet we possess little more than anecdotes concerning the relationship among deposition (seeds/m2), source strength (seeds/m2), and distance. In this paper we derive two simple models for long-distance deposition. The models are tested at the scale of 100–1600 m from the source and found to be within 5-fold of the observed deposition. There is no discernable decline in deposition for the range 300–1600 m. While we hesitate to extend model predictions to greater distances, both the models and the empirical results allow us to assert that rare wind-dispersed species in woodlots (dispersal distance around 1 km) are effectively isolated from one another at the temporal scale of 1000 years. Key words: plant conservation biology, wind dispersal of seeds, metapopulations.

Field evaluation of ecological differentiation of dwarf mistletoe on shore pine and western hemlock

1976 ◽  
Vol 6 (2) ◽  
pp. 225-228 ◽  
Author(s):  
R. B. Smith ◽  
E. F. Wass
Keyword(s):  
British Columbia ◽  
Field Evaluation ◽  
Field Studies ◽  
Western Hemlock ◽  
Lake Area ◽  
Dwarf Mistletoe ◽  
Varied Composition ◽  
Coastal British Columbia ◽  
Ecological Races ◽  
Shore Pine

Hemloclc dwarf mistletoe (Arcenthobiiuntsugense (Rosend.) G. N. Jones) principally infects western hemlock (Tsugaheteropliylla (Raf.) Sarg.), but it is also damaging to shore pine (Pinuscontorta Dougl. ex Loud.) growing in coastal British Columbia. Stands of varied composition were studied in the Home Lake area of Vancouver Island to compare the levels of infection in shore pine and western hemlock. Infection of shore pine occurred whether or not infected hemlock trees were present in the stand. Observations and measurements from these field studies support indications from earlier artificial inoculation trials that two ecological races of A. tsugense exist.

Effects of Thinning on Volume Growth of Western Larch Infected with Dwarf Mistletoe in Northeastern Oregon

1989 ◽  
Vol 4 (4) ◽  
pp. 143-145
Author(s):  
Gregory M. Filip ◽  
J. J. Colbert ◽  
Catherine A. Parks ◽  
Kenneth W. Seidel
Keyword(s):  
Electrical Resistance ◽  
Volume Growth ◽  
Larix Occidentalis ◽  
Dwarf Mistletoe ◽  
Western Larch ◽  
Snow And Ice

Abstract Cubic volume growth and tree vigor of 70-year-old western larch (Larix occidentalis) with and without dwarf mistletoe (Arceuthobium laricis) were measured 15 years after thinning from above or below to residual densities of 50 to 170 ft²/ac. Vigor was assessed by cambial electrical resistance (CER). Proportional volume growth increased after thinning; was significantly related to the interaction of thinning method and residual density; and decreased with increased dwarf mistletoe severity. Thinning from above was associated with significantly higher proportional volume growth, but led to increased mortality from snow and ice damage to infected trees. CER was significantly related to severity of infection but not to treatment. Thinning is recommended in dwarf mistletoe infested stands of western larch to increase volume growth and reduce new infections in residual trees. West. J. Appl. For. 4(4):143-145, October 1989.

Growth patterns in immature and mature western hemlock stands infected with dwarf mistletoe

1984 ◽  
Vol 14 (4) ◽  
pp. 518-522 ◽  
Author(s):  
A. J. Thomson ◽  
R. B. Smith ◽  
R. I. Alfaro
Keyword(s):  
Confidence Intervals ◽  
Growth Curves ◽  
Early Growth ◽  
Growth Patterns ◽  
Western Hemlock ◽  
Stem Analysis ◽  
Dwarf Mistletoe ◽  
Infected Tree ◽  
Volume Increment ◽  
Growth Loss

Growth patterns of western hemlock, Tsugaheterophylla (Raf.) Sarg. infected with dwarf mistletoe, Arceuthobiumtsugense (Rosendahl) G. N. Jones, were studied by stem analysis. The volume increment versus age relationships of average trees were used to project growth and evaluate volume losses. Based on a particular assumption of growth loss ratios between infection classes, volume losses in moderately and severely infected trees by the age of 80 years were conservatively estimated at 15 and 25%, respectively, with respect to comparable healthy trees. As these estimates were based on projection of growth curves of average trees, confidence intervals were not calculated. Healthy trees selected from a different part of the stand generally exhibited patterns of establishment and early growth which differed from the infected trees to an extent which invalidated their use as controls for infected tree growth. Moderately infected trees were more comparable to severely infected trees from the same part of the stand. The variety of growth patterns within stands is discussed in relation to the use of the stand as a sampling unit.

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