Midwinter needle temperature and winter injury of montane red spruce (original) (raw)
Related papers
Responses of white spruce (Picea glauca) to experimental warming at a subarctic alpine treeline
Global Change Biology, 2007
From 2001 to 2004 we experimentally warmed 40 large, naturally established, white spruce [Picea glauca (Moench) Voss] seedlings at alpine treeline in southwest Yukon, Canada, using passive open-top chambers (OTCs) distributed equally between opposing north and south-facing slopes. Our goal was to test the hypothesis that an increase in temperature consistent with global climate warming would elicit a positive growth response. OTCs increased growing season air temperatures by 1.8°C and annual growing degree-days by one-third. In response, warmed seedlings grew significantly taller and had higher photosynthetic rates compared with control seedlings. On the south aspect, soil temperatures averaged 1.0°C warmer and the snow-free period was nearly 1 month longer. These seedlings grew longer branches and wider annual rings than seedlings on the north aspect, but had reduced Photosystem-II efficiency and experienced higher winter needle mortality. The presence of OTCs tended to reduce winter dieback over the course of the experiment. These results indicate that climate warming will enhance vertical growth rates of young conifers, with implications for future changes to the structure and elevation of treeline contingent upon exposure-related differences. Our results suggest that the growth of seedlings on north-facing slopes is limited by low soil temperature in the presence of permafrost, while growth on south-facing slopes appears limited by winter desiccation and cold-induced photoinhibition.
2010
The objective of this study is to describe winter and summer surface air and forest floor temperature patterns and diurnal fluctuations in high-elevation red spruce (Picea rubens Sarg.) forests with different levels of canopy cover. In 1988, a series of 10-x 10-meter plots (control, low nitrogen [N] addition, and high nitrogen addition) were established on Mount Ascutney, VT, to examine the influence of N fertilization on red spruce and balsam fir (Abies balsamea Mill.) forest N cycling, tree mortality, and forest growth. As a result of N addition to the plots, species mortality has occurred on the low N and high N plots with the control plots experiencing very little mortality. Consequently, the mortality experienced on the low N and high N plots reduced forest cover and created both patchy and open forest canopies. In 2002, we installed temperature probes on the existing high-elevation red spruce to begin describing surface air (2 cm above ground) and forest floor temperature (2 cm below ground) patterns under different levels of canopy cover. In June 2006 we established four new 10x 10-meter red spruce plots, girdling 50 percent of the trees in two plots and 100 percent in the other two plots to further test surface air and forest floor temperature ranges under an altered forest canopy. Summer diurnal fluctuations in surface air temperature were highest on the high N plots (9.5 °C to 12.8 °C) during all years except 2007, where the 100 percent girdled plots had the highest summer diurnal value, 19.7 °C. Winter diurnal fluctuations in surface air temperature were lowest on the high N plots for all years. Summer diurnal fluctuations in forest floor temperature were highest on the high N plots for all years, while the winter diurnal fluctuations in forest floor temperature showed little variability between plots. Summer mean maximum, mean minimum, and mean surface air and forest floor temperatures were higher on the high N and/or 100-percent girdled plots in any given year. Summer mean maximum air temperature was highly related to percent canopy cover (r 2 = 0.94, p=0.006). As a result of direct solar radiation and the hot air that reaches and heats the ground surface through gaps and open canopies, 1-or 2-year-old red spruce seedlings might be negatively affected.
Midwinter dehardening of montane red spruce during a natural thaw
Canadian Journal of Forest Research, 1995
We documented 3 to 14 °C of dehardening in current-year foliage of 10 mature, montane red spruce (Picearubens Sarg.) trees during a natural thaw from 12 to 21 January 1995. Mean cold tolerance was about −47 °C before the onset of thaw conditions, and individuals ranged from −38 to −52 °C. After 3 days of thaw, mean cold tolerance dropped to −39 °C, with a range of −32 to −44 °C. Trees did not regain prethaw levels of cold tolerance until sometime between 31 January and 9 February, or 10 to 20 days after subfreezing temperatures resumed. The least cold tolerant tree was at risk of injury when temperature at the field site fell to an estimated −33.8 °C on 6 February, and this same tree developed noticeably more injury than other trees when injury symptoms developed in late March. No evidence of dehardening was found in balsam fir (Abiesbalsamea (L.) Mill.) trees from the same stand. All red spruce trees also showed the potential for net assimilation of carbon during the thaw, as deter...
Canadian Journal of Forest Research, 2006
Red spruce (Picea ruberzs Sarg.) winter injury is caused by freezing damage that results in the abscission of the most recent foliar age-class. Injury was widespread and severe in the northeastern United States in 2003 and was assessed at multiple elevations at 23 sites in Vermont and adjacent states. This paper presents a spatial analysis of these injury assessments. Relationships between winter injury on dominant and codominant spruce trees and elevation, latitude, longitude, slope, and aspect were investigated with least squares regression and geographically weighted regression. Results of these analyses indicate that injury increased (1) with elevation; (2) from east to west; (3) with the degree to which plots faced west, except at the highest elevations, where injury was uniformly severe; (4) with increases in slope steepness at higher elevations, or with decreases in slope steepness at lower elevations; and (5) with the degree to which plots faced south, except at the highest elevations in northern locations, where injury was uniformly severe. Because injury was greater in areas that have historically received higher levels of acid and nitrogen depositionwestern portions of the study region, west-facing slopes, and higher elevationsobserved patterns of injury support the hypothesis that acidic and (or) nitrogen deposition act on a landscape scale to exacerbate winter injury. Greater injury on south-facing slopes suggests that sun exposure exacerbates injury or its expression.
Radiation and Temperature Responses to a Small Clear-Cut in a Spruce Forest
The Open Geography Journal, 2010
Effects of a small clear-cutting on solar radiation, soil and air temperature regimes were investigated by continuous field measurements in a spruce forest in Solling, Central Germany, during vegetation period of 2005. Five meteorological stations, installed in central part of a small clear-cut area (2.5 ha) and close to edges of a surrounding forest, allowed to quantify the spatial variability of meteorological parameters within the clear-cut and to describe the impacts of the forest on clear-cut microclimate. The differences of microclimatic conditions between the clear-cut and the surrounding forest were derived using an additional station installed inside the forest about 150 m from the clear-cut. Results showed that clear-cutting leads to significant changes of spatial and temporal patterns of solar radiation and soil temperature. Solar radiation at the clear-cut was very heterogeneously distributed and about 5-11 times higher than inside the forest. It reached maximum at northeastern part and minimum at southwestern part of the clear-cut. The daily maximal soil temperature at 10 cm depth was measured at northern parts of the clear-cut and it was by up to 6°C higher than in the forest. Daily minimal soil temperature at the clear-cut was about 1-3°C higher than in the forest, too. The main factors influencing the soil temperature patterns were seasonally changed incoming solar radiation, ground vegetation and its phenology, as well as soil moisture. The mean daily maximal air temperature measured at the clear-cut was by up to 2.5°C higher and the mean daily minimal temperature by up to 0.5°C lower than in the surrounded forest.
Reducing Solar Heat Gain during Winter: The Role of White Bark in Northern Deciduous Trees
ARCTIC, 2003
Deciduous tree species throughout the boreal forest of North America have lighter-coloured bark than do species restricted to more southern forests. We tested the hypothesis that light-coloured bark minimizes the thawing and freezing of cambium tissue during winter that could contribute to sunscald injury. During mid-winter, maximum midday cambium temperatures of south-exposed bark of white birch (Betula papyrifera Marsh.) near Timmins, Ontario, were higher for brownpainted bark (+1.6 ˚C) than for natural bark (-9.4 ˚C) and white-painted bark (-12.1 ˚C). Rates of temperature decrease after trees were shaded at midday were more rapid for brown-painted bark (0.06 ˚C/min) than for natural bark (0.03 ˚C/min) and whitepainted bark (0.03 ˚C/min). When stems of white birch, trembling aspen (Populus tremuloides Michx.), yellow birch (B. alleghaniensis Britton), and largetooth aspen (P. grandidentata Michx.) were illuminated and subsequently shaded at -10 ˚C ambient air temperature, maximum cambium temperatures and rates of cambium cooling increased with decreasing measures of whiteness. For trembling aspen in the southwest Yukon, we found that after two years, brown-painted trees had a higher incidence (35%) of wounding that resembled sunscald injury than did white-painted trees (2.5%) and natural trees (4.5%). Therefore, we suggest that light-coloured bark reduces the risk of winter sunscald injury, probably by protecting the cambium from solar heat gain in subfreezing temperatures. This physical mechanism for reducing sunscald risk may explain why the deciduous trees at the northern limit of tree growth are those with highly reflective bark.
Canadian Journal of Forest Research, 2004
Abundant winter injury to the current-year (2002) foliage of red spruce (Picea rubens Sarg.) became apparent in the northeastern United States in late winter of 2003. To assess the severity and extent of this damage, we measured foliar winter injury at 28 locations in Vermont and surrounding states and bud mortality at a subset of these sites. Ninety percent of all trees assessed showed some winter injury, and trees lost an average of 46% of all current-year foliage. An average of 32% of buds formed in 2002 were killed in association with winter injury. Both foliar and bud mortality increased with elevation and with crown dominance, and bud mortality increased with greater foliar injury. Foliar injury in 2003 at a plantation near Colebrook, New Hampshire, was more than five times the typical levels for 9 previous years of measurement and more than twice that measured for another high-injury year. Plantation data also indicated that bud mortality in 2003 was greater than previously documented and that persistent winter injury was associated with increased tree mortality. Comparisons of our data with past studies for two sites with native red spruce also indicated that damage in 2003 was greater than other recently reported, high-injury years. Because heavy foliar and bud losses can severely disrupt the carbon economies of trees, the 2003 winter injury event could lead to further spruce decline and mortality, particularly among dominant trees at higher elevations.
Temperatures at the margins of a young spruce stand in relation to aboveground height
iForest - Biogeosciences and Forestry, 2013
Air temperature was monitored at a summit of the Jizerské hory Mountains (Czech Republic) in the vicinity of the northern and southern margins of a young Norway spruce stand (tree height approx. 4.5 m) at 30, 60, 90 and 140 cm aboveground. Temperature sensors were placed at height intervals selected to represent terminal shoot heights in the planting stock of different treeheight categories (seedlings, semi-saplings and saplings). As reference, a point 30 cm aboveground in an adjacent treeless gap between stands was monitored. Measurements were taken in two periods, from April to October 2010 and 2011. Differences were evaluated in terms of mean temperature characteristics of the ground air layer in the stand gap and in each station at the stand margins. Differences in temperature extremes (minimum, maximum, range) values showed more conspicuous fluctuations than differences in mean values. The observed difference in the course of daily temperature in the ground air layer (up to 30 cm aboveground) between the stand gap and the southern margin of the spruce stand was small. The ground layer of air at the northern margin was markedly colder and showed a more stable course of temperatures. Decreasing temperature fluctuations were observed as distance from the ground increases, and frequency and intensity of ground frosts also decreased with sensors' height. At 140 cm aboveground (i.e., at approximately one-third of the spruce stand's height), differences between daily temperature characteristics at the southern and northern stand margins were small over the growing period, and the occurrence of late or early frosts showed comparable frequencies. In conclusion, higher risk of damage to small-sized planting stock due to temperature stress was confirmed for higher mountain elevations. For the reconstitution of young coniferous stands, the choice of suitable planting sites within a small clear-cut area is relevant (in terms of temperatures near the terminal shoot) only when planting stocks of small dimensions are used.