Inger Sundheim Fløistad

Research Scientist

(+47) 452 27 021
inger.floistad@nibio.no

Place
Ås H8

Visiting address
Høgskoleveien 8, 1433 Ås

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Abstract

Subalpine fir (Abies lasiocarpa (Hooker) Nuttall), which is native to western North America, is of considerable interest for Christmas tree production in northern Europe. Seedlings are usually grown from seeds under combined nursery greenhouse/outdoors conditions, but commonly show early growth cessation in the nursery, resulting in small plants for field transplanting. This increases the production time and makes the seedlings vulnerable to stressors at the planting site. Day extension with far-red (FR) light was shown to enhance elongation and delay bud set in seedlings of some woody species, but such information is limited for Abies. Here, we investigated the effects of day extension with FR, red (R), different R:FR-ratios or blue (B) light from light emitting diodes on subalpine fir seedlings grown at different temperatures. Day extension with FR or combined R-FR light, in contrast to R or B light, increased shoot elongation significantly as compared to short days without day extension, often with more growth at 18 ◦C than 24 ◦C. The FR treatments delayed terminal bud development, although bud set was not completely prevented. These results demonstrate that larger seedlings of subalpine fir seedlings for Christmas tree production can be obtained by employing day extension with FR or combined R:FR light, preferably under cool temperature.

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Abstract

Picea abies seedlings were given three different fertilization treatments in the nutrient solution by varying the potassium:nitrogen (K:N) ratios (2.5, 3.0 or 3.9 g g–1). All fertilization treatments were combined with short-day (SD) treatment or no such treatment (control). Above- and belowground growth responses in the seedlings were analyzed. The SD treatment resulted in significantly reduced shoot height, compared to untreated control, irrespective of K:N ratio. No combination of photoperiod treatment or fertilization treatment affected the root collar diameter. In the current year root fraction with diameter < 0.5 mm, the highest K:N ratio led to significantly increased root length in control plants. In each 0.1 mm root diameter class up to 0.5 mm, the highest K:N ratio significantly stimulated root growth in control plants, while the effect was less evident for SD plants. SD treatment stimulated length growth in some fine root diameter classes. We conclude that SD treatment is a good and sufficient measure to reduce height growth without compromising fine root growth of P. abies seedlings. Fertilization treatment did not significantly improve aboveground growth in SD treated seedlings, and only limited effects on root growth was seen on control plants.

Abstract

The Christmas tree industry in Norway is increasing and Abies lasiocarpa is, together with Abies nordmanniana, the most common exotic species for Christmas tree production. A. lasiocarpa today constitutes ca. 50% of the fir sold in Norway, and there is high demand for sufficient supply of high-quality seed and knowledge of seed sources with a potential for high Christmas tree quality. Two experimental plots were established to identify seed sources with potentially high survival and satisfactory Christmas tree quality. The high variation in traits on the two sites indicates promising possibilities for further selection of A. lasiocarpa clones for growing Christmas trees in Norway. Selection for late bud break to avoid spring frost is important. Pathogens were not found in any of the studied trials, but are an important factor to consider when selecting seed sources for Christmas trees. Due to the early bud break of this species, it is also of high importance to choose planting sites with minimal risks for spring frost. Good localities are slopes where the frost drains away during cold nights. In eastern Norway, A. lasiocarpa should be used with care in districts and sites where spring frost is commonly occurring.

Abstract

Natural regeneration of Norway spruce (Picea abies (L.) Karst.) is a relatively common practice in Norway on medium to low site indices. However, seedling establishment is often hampered by rapid regrowth of competing vegetation in scarified patches. The aim of our study was to examine the effect of coordinating scarification towards an expected seed-fall, by studying germination and seedling establishment in scarified patches of different age (fresh, one- and two-year-old). The experiment was conducted in two stands in southeast Norway that were clear-cut in 2007. Scarification was applied to subplots in autumn 2008–2010. To simulate seed-fall, seeds were sown in fresh scarification patches in spring 2009–2011, in one-year-old patches in 2010 and 2011, and in twoyear- old patches in 2011. Both germination and seedling survival were negatively affected by the age of the scarified patches. Germination was higher, and mortality lower, at the small fern woodland site, compared with the bilberry woodland site. Sowing in fresh patches also resulted in increased height and root collar diameter of the seedlings compared with sowing in older patches. It is likely that the competing vegetation both on the site and in the scarification patches affected the growth of the seedlings. In conclusion, the age of the scarified patches affected both germination and mortality, as well as early growth of the seedlings.

Abstract

Removal of logging residues causes significant nutrient losses from the harvesting site. Furthermore,collection of residues into piles could lead to small-scale differences in establishment conditions for seedlings. We studied the effects of stem-only (SOH) and aboveground whole-tree harvesting (WTH) on Norway spruce (Picea abies) seedling growth and pine weevil (Hylobius abietis) damage at two sites (SE and W Norway). We also compared two planting environments within the WTH plots (WTH-0: areas with no residues, WTH-1: areas where residue piles had been placed and removed before planting). In practice, one-third of the residues were left on site after WTH. After three growing seasons there were no differences for height or diameter increment between SOH and WTH (WTH-1 and WTH-0 combined) treatments. However, relative diameter increment was largest for WTH-1 seedlings and lowest for WTH-0 seedlings. Few seedlings sustained pine weevil attacks at the W Norway site, with no differences among treatments. At the SE Norway site, the percent of seedlings damaged by pine weevils and average debarked area were significantly higher after WTH (82% and 3.3 cm2) compared to SOH (62% and 1.7 cm2). We conclude that WTH may lead to spatial differences in establishment conditions.

Abstract

Knowledge about the reproduction strategies of invasive species is fundamental for effective control. The invasive Fallopia taxa (Japanese knotweed s.l.) reproduce mainly clonally in Europe, and preventing spread of vegetative fragments is the most important control measure. However, high levels of genetic variation within the hybrid F. × bohemica indicate that hybridization and seed dispersal could be important. In Norway in northern Europe, it is assumed that these taxa do not reproduce sexually due to low temperatures in the autumn when the plants are flowering. The main objective of this study was to examine the genetic variation of invasive Fallopia taxa in selected areas in Norway in order to evaluate whether the taxa may reproduce by seeds in their most northerly distribution range in Europe. Fallopia stands from different localities in Norway were analyzed with respect to prevalence of taxa, and genetic variation within and between taxa was studied using amplified fragment length polymorphism (AFLP). Taxonomic identification based on morphology corresponded with identification based on simple sequence repeats (SSR) and DNA ploidy levels (8× F. japonica, 6× F. × bohemica and 4× F. sachalinensis). No genetic variation within F. japonica was detected. All F. × bohemica samples belonged to a single AFLP genotype, but one sample had a different SSR genotype. Two SSR genotypes of F. sachalinensis were also detected. Extremely low genetic variation within the invasive Fallopia taxa indicates that these taxa do not reproduce sexually in the region, suggesting that control efforts can be focused on preventing clonal spread. Climate warming may increase sexual reproduction of invasive Fallopia taxa in northern regions. The hermaphrodite F. × bohemica is a potential pollen source for the male-sterile parental species. Targeted eradication of the hybrid can therefore reduce the risk of increased sexual reproduction under future warmer climate.

Abstract

On September 6th – 11th in 2015, the Norwegian Institute of Bioeconomy Research (NIBIO) organized The 12th International Christmas Tree Research and Extension Conference (CTREC) at Honne, Norway. Around 40 participants from Australia, Austria, Canada, Denmark, France, Greece, Hungary, Iceland, Norway, UK, and USA gathered to share skills and recent research related to Christmas tree production and marketing. Nearly 50 presentations (oral and poster) were given during the conference covering the following topics; Breeding & genetic, Insects, Tree health, Physiology, Growth conditions & integrated pest management, Postharvest, and Market & economy. Abstracts, extended abstracts or papers from all presentations are available in this proceedings.

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Abstract

Feeding by pine weevil (Hylobius abietis L.) causes severe damage to newly planted conifer seedlings in most parts of Scandinavia. We investigated the effect of planting time and insecticide treatment on pine weevil damage and seedling growth. The main objective was to study if planting in early autumn on fresh clear-cuts would promote seedling establishment and reduce the amount of damage caused by pine weevil the following season. The experiment was conducted in southern Sweden and in south-eastern Norway with an identical experimental design at three sites in each country. On each site, Norway spruce seedlings with or without insecticide treatment were planted at four different planting times: August, September, November and May the following year. In Sweden, the proportion of untreated seedlings that were killed by pine weevils was reduced when seedlings were planted at the earliest time (August/September) compared to late planting in November, or May the following year. This pattern was not found in Norway. The average length of leading shoot, diameter growth and biomass were clearly benefited by planting in August in both countries. Insecticide treatment decreased the number of seedlings killed or severely damaged in both Norway and Sweden.

Abstract

Ten exotic Abies species were tested in two field trials, where the aim was to find suitable species and provenances for Christmas tree production in coastal and fjord areas in Norway. The material included 14 provenances of Abies nordmanniana, 3 provenances of Abies bornmuelleriana, 3 provenances of Abies koreana, 2 provenances of Abies amabilis, and 1 provenance each of Abies equi-trojani, Abies alba, Abies procera, Abies homolepis, Abies nephrolepis, and Abies forrestii. Field trials were established at Gulen in Sogn og Fjordane County and at Verdal in Nord-Trøndelag County. Christmas tree classification was done seven and eight growing seasons after establishment. The Christmas tree yield was higher in Gulen (64%) than in Verdal (45%), which is situated further north. Also, the survival and the height growth were higher in Gulen than in Verdal. A more humid climate and a longer growth season in Gulen may explain some of the differences. Of the 10 species, A. nordmanniana, A. homolepis, and A. bornmuelleriana produced the highest Christmas tree yield at Gulen, while A. homolepis and A. koreana had the highest yield at Verdal. Due to early bud burst, A. equi-trojani and A. bornmuelleriana are only suited for Christmas tree growing in the best climatic areas.

Abstract

Le gel printanier peut etre dommageable pour les semis de Picea abies (L.) Karst. nouvellement plantes si leur rythme de croissance n'est pas suffisamment adapte aux conditions climatiques de la station forestiere. Les objectifs de cette etude consistaient a determiner de quelle facon le debourrement et la resistance au gel printanier sont influences par un traitement de jours courts (JC) appliques a differents moments et avec differents regimes de temperature durant la periode de formation des bourgeons. A la suite d'un entreposage hivernal, la resistance au gel a ete evaluee apres une, trois et cinq semaines dans des conditions de forcage. Le traitement JC a avance le debourrement comparativement aux semis temoins. Par comparaison, le moment du traitement et les differentes temperatures ont eu peu d'effet sur le debourrement. Le traitement JC a augmente la resistance au gel des aiguilles d'un an pendant la periode de desendurcissement. Applique tot, le traitement JC a augmente la resistance au gel des aiguilles d'un an et le diametre au collet comparativement a une application plus tardive. Il est important que la periode de noirceur atteigne une duree critique lorsque le traitement JC prend fin pour eviter une deuxieme eclosion des bourgeons. Des temperatures basses a la suite du traitement JC ont augmente la resistance au gel des aiguilles et diminue celle de la tige. Les effets contraires de la temperature sur differents tissus vegetaux demontrent l'importance d'examiner differents tissus apres des essais de gel-degel. Spring frost may result in detrimental damage in newly planted Picea abies (L.) Karst. seedlings if their growth rhythm is not sufficiently adapted to the climatic conditions on the forest site. The aims of this study were to evaluate how bud break and spring frost hardiness were influenced by short-day (SD) treatments with different timing and different temperature regimes during bud formation. Following winter storage, frost hardiness was tested after 1, 3 and 5 weeks in forcing conditions. The SD treatment advanced bud break compared with the control seedlings. In comparison, the effects of timing and the different temperatures on bud break were small. The SD treatment improved frost hardiness in first-year needles during dehardening. The early SD treatment resulted in improved frost hardiness in first-year needles and greater root collar diameter compared with later SD treatment. To avoid a second bud flush, it is important that a critical night length is attained when the SD treatment terminates. Low temperatures following the SD treatment resulted in increased hardiness of the needles and decreased hardiness of the stems. The contrasting effect of temperature in different plant tissues demonstrates the importance of examining different tissues following freezing tests.

Abstract

In trees adapted to cold climates, conditions during autumn and winter may influence the subsequent timing of bud burst and hence tree survival during early spring frosts. We tested the effects of two temperatures during, dormancy induction Mid mild spells (MS) during chilling, on the timing of bud burst in three Picea abies (L.) Karst. provenances (58-66 degrees N). One-year-old seedlings were induced to become dormant at temperatures of 12 or 21 degrees C applied during 9 weeks of short days (12-h photoperiod). The seedlings were then moved to cold storage and given either continuous chilling at 0.7 degrees C (control), or chilling interrupted by one 14-day MS it either 8 or 12 degrees C. Interruptions with MS were staggered throughout the 175-day chilling period, resulting in 10 MS differing in date of onset. Subsets of seedlings were moved to forcing conditions (12-h photoperiod, 12 degrees C) throughout the chilling period, to assess dormancy status different timings of the MS treatment. Finally, after 175 days of chilling, timing of bud burst was assessed in a 24-h photoperiod at 12 degrees C (control and MS-treated seedlings). The MS treatment did not significantly affect days to bud burst when given early (after 7-35 chilling days). When MS was given after 49 chilling days or later, the seedlings burst bud earlier than the controls, and the difference increased with increasing length of the chilling period given before the MS. The 12 degrees C MS treatment was more effective than the 8 degrees C MS treatment, and the difference remained constant after the seedlings had received 66 or more chilling days before the MS treatment was applied. In all provenances, a constant temperature of 21 degrees C during dormancy induction resulted in more dormant seedlings (delayed bud burst) than a constant temperature of 12 degrees C, but this did not delay the response to the MS treatment.

Abstract

According to previous studies, short day (SD) treatment may increase frost hardiness in Picea abies (L.) Karst. seedlings during shoot elongation the next year. The purpose of this study was to examine how timing of the SD treatment affects spring frost hardiness. The following four treatments were applied in the first growth period: natural photoperiod (Nat), or SD treatment (8/16 h, day/night) either from 14-28 July (SD1), 28 July-11 August (SD2), or 11 20 August (SD3). After 125 days in the cold store (October-January), the seedlings were transferred to forcing conditions (20-25oC, 24 h photoperiod) followed by freezing tests at 3, -5, -7 and 9oC when most seedlings had reached bud break stage 7 (Krutzsch index). Seedling height measurements and analyses of carbohydrate status, nitrogen concentration and dry weight of needles after cold storage were done to examine the treatments` impact on seedling quality. SD treatment reduced visual freezing injury to current- and first-year shoots. Mortality occurred at –7 and –9oC and was significantly higher in treatments Nat and SD1 (43% in both) than in the SD2 (23%) and SD3 (15%) treatments. Seedlings from the late SD treatments also showed better height growth and developed more shoots from dormant buds after freezing to –3 and –5oC. Collectively, these findings demonstrate the importance of proper timing of the SD treatment in relation to the seedlings’ natural growth rhythm.