Dehardening and budburst of Douglas-fir seedlings raised in three Pacific Northwest nurseries

1989 ◽  
Vol 19 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Ursula K. Schuch ◽  
Mary L. Duryea ◽  
L. H. Fuchigami

This study was undertaken to test whether nursery location affected dehardening and budburst of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings from two seed sources. The seedlings, raised at three nurseries in Oregon and Washington, were measured with a whole-plant freezing test in January, February, and March, 1986. In general, seedlings raised at the nursery at highest elevation, and in a few cases, trees from the most northerly nursery, were more frost resistant than trees from a coastal nursery. From January to March, seedlings from the highest (975 m) seed source had less-hardy stem tissue than seedlings from the coastal source (450 m). A growth-chamber experiment confirmed the outdoor dehardening studies. A constant temperature of +5 °C with a 16-h photoperiod maintained cold hardiness, whereas +10 and +15 °C with a 16-h photoperiod promoted rapid dehardening after 20 days. The nursery environment influenced budburst; trees raised in the coastal nursery burst bud significantly earlier than trees from the other two nurseries. Trees of different provenances from the same nursery burst terminal buds only 2 days apart.

1989 ◽  
Vol 19 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Ursula K. Schuch ◽  
Mary L. Duryea ◽  
L. H. Fuchigami

Two-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings from two seed sources raised in three nurseries in Oregon and Washington were tested for differences in frost hardiness between September 1985 and January 1986. The objective was to determine whether nursery location significantly influenced hardiness. Seedlings were tested by whole-plant freezing to various temperatures, followed by six evaluations of frost hardiness of needle, bud, and stem tissues. Seedlings at the highest nursery had the hardiest needles and those at the coastal nursery the least hardy needles. Bud hardiness, calculated over time, differed between seed sources but not among nurseries. Stem acclimation followed the pattern of needle hardening from November to January. A regression equation calculated to predict frost hardiness from climatic data and elevation of the nurseries showed that elevation, photoperiod, and number of days of frost were the most important independent factors (R2 = 0.29).


1987 ◽  
Vol 17 (11) ◽  
pp. 1371-1378 ◽  
Author(s):  
Mary L. Duryea ◽  
Steven K. Omi

Seedlings from nine Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seed sources were top pruned at six nurseries in the Pacific Northwest and then planted at field sites in their own seed zones and on one common site. Seedlings pruned tall (25 cm) and early in the growing season flushed again about 5 weeks after pruning and set bud 2 weeks later than unpruned controls. Nursery yield (number of shippable seedlings) was the same for tall–early pruned and control seedlings; however, pruning increased the number of seedlings with multiple leaders from 10 to 38%. Pruned seedlings were smaller than unpruned seedlings in height, stem diameter, bud length, and root and shoot weights at the time of field planting. First-year field survival and growth were the same for pruned and unpruned seedlings at all planting sites. Second-year field growth of pruned seedlings was generally greater than that of unpruned seedlings, and frequency of multiple leaders was reduced. However, pruned seedlings were still shorter than unpruned ones after 2 years. Field growth was greater when seedlings were pruned early rather than late (end of growing season) and tall rather than short (15 cm). Late–short pruning yielded shorter seedlings with smaller terminal buds and should be avoided. If pruning benefits nurseries by expediting grading, handling, and planting and, perhaps, enhancing growth later in the field, it should be continued as a cultural practice. However, longer-term measurements are needed for assessing the full effect of pruning on seedling growth.


1990 ◽  
Vol 7 (2) ◽  
pp. 86-89 ◽  
Author(s):  
Mark E. Kubiske ◽  
Marc D. Abrams ◽  
James C. Finley

Abstract Cut Douglas-fir Christmas trees grown in Pennsylvania from Rocky Mountain seed sources and coastal trees grown in the Pacific Northwest and shipped into Pennsylvania were compared for keepability. Following various cold treatments, the cut ends of trees were placed in water in an indoor display area. Coastal trees placed in a freezer at - 29°C for 24 h had 89 ± 5.1% (mean ± standard error) needle loss after one day of display, while Rocky Mountain origin trees exhibited only 3 ± 2.0% needle loss after 1 day and 50 ± 5.6% needle loss after 18 days. Coastal produced trees exposed to temperatures > - 12°C had 50 ± 9.8% needle loss at the end of the experiment, while Rocky Mountain trees ended with 22 ± 3.2% needle loss. Four additional treatments consisted of trees placed on an outdoor lot and periodically moved indoors to simulate Christmas tree market activity. Again, there was a significant difference between trees from coastal and Rocky Mountain sources, with 57.2 ± 4.3% and 11.8 ± 1.2% needle loss after 3 days, respectively. By the end of the 23 day experiment, the coastal trees were essentially devoid of needles, whereas Rocky Mountain trees had an average of only 20% needle loss. Coastal trees also exhibited a very noticeable loss of color and lustre. North. J. Appl. For. 7:86-89, June 1990.


2019 ◽  
Vol 118 (1) ◽  
pp. 1-13 ◽  
Author(s):  
J Bradley St. Clair ◽  
Glenn T Howe ◽  
Jennifer G Kling

Abstract The 1912 Douglas-Fir Heredity Study is one of the first studies undertaken by the US Forest Service, and one of the first forest genetics studies in North America. The study considers provenance variation of 120 parent trees from 13 seed sources planted at five test sites in the Pacific Northwest. The unique, long-term nature of the study makes it valuable to revisit and consider its biological and historical significance. This analysis considers how far climatically Douglas-fir populations may be moved without incurring unacceptable declines in growth and survival. Results indicate that Douglas-fir seed sources may be moved at least 2° C cooler or warmer and still retain good long-term survival and productivity. However, projected future climate change beyond 2° C may lead to lower survival and productivity. One option to address these concerns is assisted migration; however, if seed sources are moved beyond 2–3° C to a cooler climate in anticipation of warming, or from a more continental to a maritime climate, we are likely to see increased mortality and associated losses in productivity in the near-term. Lessons from this study include: (1) pay attention to good experimental design; we were able to overcome limitations from the design by using new statistical approaches; (2) maladaptation may take time to develop; poorer survival was not evident until more than two decades after planting; and (3) long-term studies may have value for addressing new, unforeseen issues in the future.


2000 ◽  
Vol 15 (3) ◽  
pp. 129-136 ◽  
Author(s):  
T. S. Anekonda ◽  
W. T. Adams ◽  
S. N. Aitken

Abstract Operational methods are needed for screening genotypes in breeding programs for adaptive traits. In this article, we present a detailed description of one procedure for screening improved coastal Douglas-fir seedlings and saplings for cold hardiness, based on research results of the Pacific Northwest Tree Improvement Research Cooperative. Artificial freeze testing of detached shoots from genetic tests, followed by visual scoring of injury, has proved to be an efficient, reliable, and cost-effective method of screening large numbers of genotypes. Relevant research results are summarized, and practical details of this methodology are presented for straightforward implementation by Douglas-fir breeders and researchers. West. J. Appl. For. 15(3):129-136.


1995 ◽  
Vol 124 (1) ◽  
pp. 11-16 ◽  
Author(s):  
R. P. Collins ◽  
I. Rhodes

SUMMARYChanges in the stolon carbohydrate contents (water-soluble and total non-structural) of four white clover populations were measured at the beginning and end of winter. Three of the populations were of Swiss origin - two of these were from high-altitude pastures, and the other from a valley location. Grasslands Huia was measured as a control variety. Levels of both types of carbohydrate declined during the winter in all populations. The Swiss populations from high altitudes contained the highest levels of both carbohydrate types.An artificial freezing test was carried out on stolon segments collected from a range of clover populations (including the two high-altitude Swiss clovers) growing in field plots in January, and values of ‘lethal dose 50’ (LD50) were calculated. The two Swiss populations had the lowest LD50 values, indicating a greater intrinsic tolerance to freezing in those plants than in the other populations (of lowland temperate origin).One of the Swiss populations, Ac3785, was grown under two temperature regimes and short daylength to determine whether its tolerance to freezing increased with time. Significant increases in tolerance occurred after 8 days at 2 °C, but plants grown at 8 °C showed no change in tolerance even after 30 days.The results suggest that (i) stolon carbohydrate content is an important factor in the overwintering of white clover, (ii) there is a considerable amount of genetic variation in cold tolerance within white clover, (iii) artificial freezing tests can provide a method of predicting the survival of clover stolons during winter and (iv) the cold hardiness of white clover increases with time spent at temperatures near 0 °C under short daylengths.


Author(s):  
Marzena Niemczyk ◽  
Daniel J. Chmura ◽  
Jarosław Socha ◽  
Tomasz Wojda ◽  
Piotr Mroczek ◽  
...  

AbstractThe contribution of Douglas-fir (Df) to European forests is likely to increase as the species is a potential adaptation option to climate change. In this study, we investigated growth and survival of Df seed sources to fill a knowledge gap regarding recommendations for the future use of Df provenances in Poland. Our experimental test site represents the most continental climate among all Df trials installed in the IUFRO 1966–67 test series in Europe. At this unique single site, we evaluated the performance of 46 Df provenances from North America, and nine local landraces of unknown origin. Repeated measurements of tree diameter, height, and volume were analysed, to age 48, representing integrated responses to geographic and climatic conditions. Significant variation in survival and productivity-related traits were found, with the interior Df provenances performing best, in contrast to previous European reports. The higher survivability and volume of the interior provenances resulted from their superior frost resistance. The low precipitation seasonality at the location of seed origin provided an additional advantage to the trees at the test site. Geographic and climatic factors of seed origin explained most of the variation in productivity (77 and 64%, respectively). The tested landraces exhibited diverse performance, implying that naturalized local seed sources in Poland need improvement and perhaps enrichment with new genetic material from North America, while considering geography and climate. Assisted migration programs should consider the limitations imposed by both frost and drought events in guiding future Df selections for continental climates. Further field testing, early greenhouse screening and DNA testing are also recommended.


1976 ◽  
Vol 27 (6) ◽  
pp. 779 ◽  
Author(s):  
D Gramshaw

Germination of Lolium rigidum seeds, in the light (12 hr day length) and in the dark, was studied at constant and alternating (12/12 hr) temperatures in the range 8–35°C. Seeds had after-ripened for 22 weeks. Different constant temperature optima for germinability were found: 27° in light and 11° in dark. Germinability at alternating temperatures in darkness was determined solely by the minimum temperature of the alternation, and there was no response to thermoperiodicity per se. In contrast, light and alternating temperature appeared to interact to increase germinability, although the highest germinability occurred only when the maximum temperature was close to the optimum constant temperature, i.e. about 27°. Germination in both light and dark was most rapid where either the constant or the average temperature of an alternating regime was between 18 and 29°. Below 18° germination rates decreased markedly, and at 8°, rates were one-third of those at 18°. Seeds germinated more slowly in light than in darkness at all temperatures, but the differences were small relative to the effects of low temperatures.In another study, seeds collected from plants naturalized in eight different localities in the cereal belt of Western Australia and subsequently planted together in two contrasting environments were examined for germinability at 24/12°C in light and dark 18 weeks after harvest. Dark germinability differed between seed sources but not between planting sites, and ranged between 78 and 93%. Exposure of germinating seeds to light substantially alleviated dormancy in seeds from all sources.


2015 ◽  
Vol 398 (1-2) ◽  
pp. 281-289 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato

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