Effects of timing of soil frost thawing on Scots pine (original) (raw)
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Delayed soil thawing affects root and shoot functioning and growth in Scots pine
Tree Physiology, 2008
In boreal regions, soil can remain frozen after the start of the growing season. We compared relationships between root characteristics and water relations in Scots pine (Pinus sylvestris L.) saplings subjected to soil frost treatments before and during the first week of the growing period in a controlled environment experiment. Delayed soil thawing delayed the onset of sap flow or totally blocked it if soil thawing lagged the start of the growing period by 7 days. This effect was reflected in the electrical impedance of needles and trunks and in the relative electrolyte leakage of needles. Prolonged soil frost reduced or completely inhibited root growth. In unfrozen soil, limited trunk sap flow was observed despite unfavorable aboveground growing conditions (low temperature, low irradiance, short photoperiod). Following the earliest soil thaw, sap flow varied during the growing season, depending on light and temperature conditions, phenological stage of the plant and the amount of live needles in the canopy. The results suggest that delayed soil thawing can reduce tree growth, and if prolonged, it can be lethal.
Forest Ecology and Management, 2015
Climate change may increase air temperature and decrease snowpack in the boreal zone. Due to declined insulating snow cover, tree roots may be exposed to too low soil temperatures that may be reflected in shoot growth. We studied the effects of soil freezing and delayed thawing on vegetative buds, needles and shoots in a 47-year-old boreal stand of Norway spruce (Picea abies L. Karst). The treatments in two winters of 2005/06 and 2006/07 were: (i) natural snow accumulation and melting (CTRL), (ii) artificial snow removal during winter (OPEN), and (iii) the same as OPEN, but the ground was insulated in early spring to delay soil thawing (FROST). More soil freezing occurred in OPEN and FROST than CTRL, and soil thawing was delayed in FROST as compared to the two other treatments. The formation of new buds, and consequently the number of new shoots were reduced in FROST. The shoot elongation was reduced and the needle cross-sectional area was smaller in FROST compared to OPEN and CTRL. As the soil temperature in both OPEN and FROST was the same during winter, the wintertime soil frost could not be the reason for the changes. Instead, the delayed soil thawing and warming towards summer seemed to hamper the root function and thus reduced the growth of above ground part of the trees. Timing of soil warming in spring appeared to be an important factor for the vegetative bud formation and shoot growth. Thus, on sites prone to soil frost and low soil temperatures, forest management practices should be planned for a proper stand development.
2008
Seedlings received either a single (September 16) or double (September 16 and 23) application of fall fertilizer. Seedling morphology and cold hardiness were evaluated in November of 2005 (1+0s) and 2006 (2+0s). Seedling morphological attributes were the same regardless of application method (single versus double). Seedling height and number of needle primordia increased significantly with increased fertilizer rate at the end of both growing seasons. In general, cold hardiness (measured by freeze-induced electrolyte leakage [FIEL] test) increased at the end of the 1+0 season in seedlings that received fall fertilization as either a single or double application. At the end of the 2+0 season, however, cold hardiness decreased (7% to 30%) with increased fertilizer rate in seedlings that received a single application of fall fertilization, but increased (15% to 50%) with fertilizer rate in seedlings that received double applications compared to controls. We are following these seedlings after outplanting to verify potential benefits of fall fertilization on seedling field performance.
Environmental and Experimental Botany, 2011
Climate change may cause a decrease in snow cover in northern latitudes. This, on the other hand, may result in more severe soil frost even in areas where it is not common at present, and may lead to increased stress on the tree canopy. We studied the effects of snow removal and consequent changes in soil frost and water content on the physiology of Norway spruce (Picea abies [L.] Karst.) needles and implications on root biomass. The study was conducted at a 47-year-old Norway spruce stand in eastern Finland during the two winters of 2005/06 and 2006/07. The treatments in three replicates were: (i) natural snow accumulation and melting (CTRL), (ii) artificial snow removal during the winter (OPEN), and (iii) the same as OPEN, but the ground was insulated in early spring to delay soil thawing (FROST). In spite of the deeper soil frost in the OPEN than in the CTRL treatment, soil warming in spring occurred at the same time, whereas soil warming in the FROST was delayed by 2 and 1.5 months in 2006 and 2007, respectively. The soil water content was affected by snow manipulations, being at a lower level in the OPEN and FROST than CTRL in spring and early summer. The physiological measurements of the needles (e.g. starch, carbon and nitrogen content and apoplastic electrical resistance) showed differences between soil frost treatments. The differences were mostly seen between the CTRL and FROST, but also in the case of the starch content in early spring 2007 between the CTRL and OPEN. The needle responses in the FROST were more evident after the colder winter of 2006. The physiological changes seemed to be related to the soil temperature and water content in the early growing season rather than to the wintertime soil temperature. No difference was found in the fine root (diameter < 2 mm) biomass between the treatments assessed in 2007. In the future, conditions similar to the OPEN treatment may be more common than at present in areas experiencing a thick snow cover. The present experiment took place over the course of two years. It is possible that whenever thin snow cover occurs yearly, the reduced starch content during the early spring may be reflected in the tree growth itself as a result of reduced energy reserves.
New Forests, 1997
Damage to containerized forest seedlings due to freezing can occur in the fall or early winter in Canadian forest nurseries. The following spring, damage to shoots and impairment of growth is observed. The objectives of this experiment were to measure the impact of late fall low temperatures (0° to --30°C) on whole seedlings of the three most common species used for reforestation in Quebec: black spruce (BS), white spruce (WS) and jack pine (JP). Impacts of freezing temperatures on (i) whole seedling and apical bud mortality, (ii) shoot growth and root mortality, (iii) stem electrical resistance, (iv) shoot and root water relations, (v) concentrations of N, P, K, Ca, Mg, and total sugars in shoots were assessed. JP showed the highest rate of whole seedling mortality while WS showed the highest rate of apical bud mortality. JP was the most severely affected: destruction of the root system at low temperatures as well as a reduction of shoot growth and stem diameter and a decrease (more negative) in shoot and root water potential. WS showed a reduction of shoot growth despite no apparent damage to the root system at low temperatures. BS was not affected by temperatures as low as --30°C. Nutrient and sugar concentrations were not affected by low temperature treatments.
Canadian Journal of Forest Research, 2002
The effects of induced root freezing injury on 2+0 white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) BSP), and jack pine (Pinus banksiana Lamb.) seedlings were studied. Hardened seedlings were exposed to freezing during the fall and cold stored until planting. Seedlings were planted in spring on two field sites with different soil moisture levels (wet or dry). Seedling morphology and physiology were measured periodically during the first growing season, and mortality was evaluated at the end of the season. With the exception of June measurements on the wet site, where daytime water potential fell as low as-2.0 MPa, root damage did not seriously affect shoot water potential. Generally, stomatal conductance decreased with increasing root damage. Net photosynthesis on both sites decreased between 22 and 39% with increasing root damage. Root damage did not affect the ratio of intercellular to ambient CO 2 concentration. As well, reductions in the nitrogen concentration of current-year foliage with increasing root damage were observed, suggesting that the observed reductions in net photosynthesis were caused by nonstomatal factors. Root growth was greater on the wet site than on the dry site, particularly between August and October, when mean soil minimum temperatures were lower on the dry site. On both sites, aerial dry mass was only slightly affected by root damage in July and August, but the effect of damage became more pronounced in October on the wet site. Black spruce and white spruce seedling mortality began being affected when approximately 50% of the root systems were damaged, while jack pine mortality was affected starting at 40% damage. Root damage levels of 50% caused 2.0 and 1.5 cm reductions in annual height increment of white spruce and black spruce, respectively, and 40% damage caused a reduction of 1.0 cm in annual height increment of jack pine. Résumé : Les effets des dommages racinaires causés par le gel ont été étudiés chez des semis 2+0 d'épinette blanche (Picea glauca (Moench) Voss), d'épinette noire (Picea mariana (Mill.) BSP) et de pin gris (Pinus banksiana Lamb.). Des semis endurcis ont été exposés au gel durant l'automne avant d'être entreposés en chambre froide. Au printemps suivant, ces semis ont été plantés sur deux sites ayant des teneurs en eau du sol distinctes (mouilleux et sec). La morphologie et la physiologie des semis ont été mesurées périodiquement durant la première saison de croissance. La mortalité a été évaluée à la fin de la saison. À l'exception des mesures prises sur le site mouilleux en juin, où des valeurs de-2,0 MPa ont été observées, les dommages racinaires n'ont pas sérieusement affecté le potentiel hydrique du xylème. Généralement, la conductance stomatique a diminué avec l'augmentation des dommages. Des diminutions de 22 à 39% de la photosynthèse nette ont été observées sur les deux sites avec l'augmentation des dommages. Les dommages aux racines n'ont pas affecté le ratio de la concentration intercellulaire en CO 2 sur la concentration ambiante en CO 2 , mais des réductions de la teneur en azote du feuillage de l'année courante ont été observées, indiquant que les diminutions de la photosynthèse nette ont été causées par des facteurs non-stomatiques. La croissance racinaire a été plus élevée sur le site mouilleux, particulièrement entre août et octobre alors que les températures minimales moyennes du sol ont été plus basses sur le site sec. Sur les deux sites, l'effet des dommages racinaires sur la biomasse aérienne a été léger en juillet et en août, mais s'est accentué en octobre sur le site mouilleux. Pour l'épinette noire et l'épinette blanche, la mortalité a été perceptible lorsque environ 50% du système racinaire était endommagé. Pour le pin gris, la mortalité a été perceptible à partir de 40% de dommages. Des dommages racinaires de 50% ont causé des réductions de croissance en hauteur de 2,0 et 1,5 cm respectivement pour l'épinette blanche et l'épinette noire. Pour le pin gris, des dommages racinaires de 40% ont provoqué une réduction de croissance en hauteur de 1,0 cm. Dumais et al.
Frontiers in Plant Science, 2015
Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, 1.5 • • +
European Journal of Forest Research, 2014
Determining the adaptability to abiotic conditions and potential establishment success of tree species needs to be conducted before attempting to use a species in large-scale afforestation programs. In this study, the chemical and physiological performance of four Turkish red pine (Pinus brutia Ten.) provenances was investigated after exposure to artificial cold temperature treatments to determine their adaptability to cold environment for potential use in afforestation programs. Seeds were sown and raised for 24, 28, and 32 weeks and exposed to decreasing temperatures in an artificial freezer. Relative electrolyte leakage, chlorophyll fluorescence, and carbohydrate concentrations were measured to determine the variability between provenances. Results showed that diameter and height growth did not vary with origin for each of the three growth stages measured. Root electrolyte leakage values differed between provenances, confirming that cold stress was effectively causing physiological damages when plants were exposed to temperature at-15°C and below. The variability observed in the relationship between provenances and cold hardiness responses can be attributed to tree-to-tree variability within provenances and microsites conditions. There was generally no significant difference in chlorophyll fluorescence between provenances, also attributed to low genetic variation between provenances. Carbohydrate concentrations were also very variable and varied significantly among growth stages and provenances. High-altitude provenances had higher soluble carbohydrates concentrations in several cases, suggesting a relationship between altitude, soluble sugars, and cold hardiness. However, these trends were not consistent; therefore, we suggest that such hypotheses be confirmed through more comprehensive further studies. Keywords Cold hardiness Á Roots REL Á Stem REL Á Chlorophyll fluorescence Communicated by A. Weiskittel.
The effect of late summer fertilization on the frost hardening of second-year Scots pine seedlings
New Forests, 1997
In this study the effect of summer fertilization on the initiation of frost hardening of containerized second-year Scots pine (Pinus sylvestris L.) seedlings is studied. During the second growing season three different fertilization programs (water soluble NPK with micronutrients) determined by electrical conductivity of peat water extract (0.2, 0.5 and 1.2 mS cm-1) were initiated. The growth and nutrient concentrations