Current issue: 58(4)

Scopus CiteScore 2023: 3.5
Scopus ranking of open access forestry journals: 17th
PlanS compliant
Select issue
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'heat sums'

Category : Article

article id 5536, category Article
Roar Skuterud, Jon Dietrichson. (1994). Budburst in detached birch shoots (Betula pendula) of different varieties winter-stored in darkness at three different temperatures. Silva Fennica vol. 28 no. 4 article id 5536. https://doi.org/10.14214/sf.a9176
Keywords: Betula pendula; climatic change; budburst; buds; frost; developmental stages; heat sums; threshold temperatures
Abstract | View details | Full text in PDF | Author Info

Budburst timing and the relationship to storage temperature and duration were investigated in four varieties (entries) of 1–2 metres tall silver birch (Betula pendula Roth) trees. A total of 2,160 shoots were sampled, and the material stores in darkness at 0, 3 or 6 °C from November 29, 1993. When the shoots were placed in storage, they had been through a period of 29 days with temperatures below 0°C (since October 15). By that time the autumn dormancy was assumed already broken, and the trees were expected to respond to increased temperature by bud development. On January 4, 1994, and on four subsequent dates, January 19, February 1, March 4 and March 17, shoots were taken out of storage and set in growth chambers at 9, 12 or 15°C. The time to budburst was recorded.

Duration of storage, storage temperatures and varieties were all highly significant for budburst. The interaction terms were of less statistical importance. Based on the contrast between the three different growth chamber environments, three different methods were used to calculate the threshold temperatures for each entry. In spite of the pre-selection of variable budburst performers, the threshold values, varying between 0°C to -2°C, could not be shown to be statistically different. According to the results, the time of budburst changes in accordance with both winter and spring temperatures, being extremely early after a mild winter and warm spring, given sufficient autumn chilling. The similarities in the threshold temperatures indicate that the ranking in earliness between varieties will most likely be the same from year to year without regard to climate change.

  • Skuterud, E-mail: rs@mm.unknown (email)
  • Dietrichson, E-mail: jd@mm.unknown
article id 5535, category Article
Mats Hannerz. (1994). Predicting the risk of frost occurrence after budburst of Norway spruce in Sweden. Silva Fennica vol. 28 no. 4 article id 5535. https://doi.org/10.14214/sf.a9175
Keywords: Norway spruce; Picea abies; Sweden; provenances; budburst; frost; developmental stages; heat sums
Abstract | View details | Full text in PDF | Author Info

Temperature sums required for budburst in various Norway spruce (Picea abies (L.) H. Karst.) provenances were determined, and weather statistics were then used to predict the risk of potentially damaging frosts at 11 locations in Sweden. Frost risk was quantified as the probability of a frost occurring within 100 day-degrees (two weeks) after budburst. The examples provided show that a spruce seedling from central Sweden has to sustain almost twice as many frost occassions as a seedling from Belorussia, when planted in southern and central Sweden. The method presented here can be used for mapping early summer frost risk in Sweden and for supporting provenance transfer guidelines.

  • Hannerz, E-mail: mh@mm.unknown (email)

Register
Click this link to register to Silva Fennica.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content
Your selected articles