Landscape-scale spatial patterns of winter injury to red spruce foliage in a year of heavy region-wide injury

2006 ◽  
Vol 36 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Brynne E Lazarus ◽  
Paul G Schaberg ◽  
Gary J Hawley ◽  
Donald H DeHayes

Red spruce (Picea rubens 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 deposition — western portions of the study region, west-facing slopes, and higher elevations — observed 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.

1996 ◽  
Vol 26 (6) ◽  
pp. 918-927 ◽  
Author(s):  
Daniel K. Manter ◽  
William H. Livingston

Red spruce (Picea rubens Sarg.) decline has been observed in northeastern North America for the last 30 years. A major inciting stress involved in this decline is freezing injury of foliage. The objectives of this study were the following: (i) to examine how photosynthesis, needle electrolyte leakage, chlorophyll loss, needle reddening, needle loss and bud break respond to single freezing events down to −45 °C on 3-year-old seedlings; (ii) to test if faster thawing rates increase the amount of freezing injury; and (iii) to measure how Rhizosphaera kalkhoffii Bubák inoculations interact with freeze-injured needles. Two trials, one of 60 seedlings and one of 80 seedlings, were conducted. The second trial had half the seedlings covered with plastic bags for doubling the thawing time. Photosynthesis, as measured by gas exchange, was consistently the most sensitive measure, detecting nonvisible injury on uncovered seedlings (p < 0.05) at −25 °C. Measurements detecting freezing damage on covered, slower thawing seedlings were photosynthesis, chlorophyll loss, and percent budbreak. Faster thawing rates increased the amount of injury ca. 2- to 3-fold after freezing to −35 or −45 °C for all measures. Infection by R. kalkhoffii increased 40–83% after freezing needles to −40 or −45 °C. Fungal inoculations caused ca. 40–60% reduction in photosynthesis on needles frozen to −40 or −45 °C. This study suggests that two new factors can increase freezing injury on red spruce needles: a faster thawing rate and fungal (R. kalkhoffii) infection. These results are consistent with the growing knowledge that freezing injury is a complex phenomenon in red spruce.


Castanea ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. 128
Author(s):  
John R. Butnor ◽  
Brittany M. Verrico ◽  
Kurt H. Johnsen ◽  
Christopher A. Maier ◽  
Victor Vankus ◽  
...  

2021 ◽  
Author(s):  
Anna Schneider ◽  
Alexander Bonhage ◽  
Florian Hirsch ◽  
Alexandra Raab ◽  
Thomas Raab

&lt;p&gt;Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.&lt;/p&gt;&lt;p&gt;We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils.&amp;#160;The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.&lt;/p&gt;


2000 ◽  
Vol 78 (7) ◽  
pp. 941-956 ◽  
Author(s):  
Om P Rajora ◽  
Alex Mosseler ◽  
John E Major

Red spruce (Picea rubens Sarg.) has become increasingly rare across large portions of its range in eastern North America as a result of a general and widespread decline over the past century. Genetic diversity, population genetic structure, outcrossing rates in the filled seeds, and actual inbreeding levels were characterized in five small, isolated, remnant red spruce populations from the disjunct northwestern limits of its range in Ontario and five populations from the larger, more extensive Maritime populations of Nova Scotia and New Brunswick to determine genetic and reproductive status, to provide some benchmarks for monitoring genetic changes resulting from isolation and restricted population sizes, and to assist the development of restoration and conservation strategies. Thirty-seven allozyme loci coding for 15 enzymes were used for genetic diversity assessments, and six of the most polymorphic loci were used for mating system determination. On average, 29.1% (95% criterion) of the loci were polymorphic, the number of alleles per locus was 1.60, and the observed and expected heterozygosities were 0.097 and 0.100, respectively. The Ontario populations were comparable to or slightly less genetically variable than those from the Maritimes. Only 4.7% of the detected genetic variation was among stands; the remainder was among individuals within stands. The Maritime populations were genetically less differentiated from each other than those in Ontario. With the exception of three Maritime populations clustering tightly in one group, there was no clear separation of Ontario red spruce populations from Maritime red spruce populations based on genetic distance as well as canonical discriminant analyses. The average multilocus (tm) and single-locus (ts) population outcrossing rates were 0.595 and 0.558, respectively, indicating a comparatively high tolerance for inbreeding up to the filled seed stage of development in red spruce. The Ontario populations, on average, showed higher outcrossing rates (tm = 0.654, ts = 0.641) than the Maritime populations (tm = 0.535, ts = 0.475). Individual family outcrossing rates were similar to their respective population outcrossing rates and no significant differences were observed among families within populations for the multilocus estimates. When such high levels of inbreeding in filled seeds were combined with the proportions of empty (post-pollination-aborted) seeds, it appears that actual inbreeding levels may vary from 48 to 86%. The highest inbreeding levels occurred in the smallest, most isolated Ontario populations and in those populations most likely to have been affected by poorer pollination conditions. Allozyme variation indicates that in the short term, extant remnants of Ontario red spruce have maintained their genetic diversity and integrity. For artificial restoration of red spruce in Ontario, local seed sources could be used without undue concern over losses of genetic diversity. However, over the longer term, genetic drift and inbreeding may be expected to result in further losses of genetic diversity and (or) reproductive fitness if population sizes, numbers, and distribution continue to decline.Key words: Picea rubens, allozymes, gene conservation, restoration, genetic diversity, population structure, outcrossing rates, inbreeding.


Ecosystems ◽  
2020 ◽  
Author(s):  
Marina Roth ◽  
Hans-Gerhard Michiels ◽  
Heike Puhlmann ◽  
Carina Sucker ◽  
Maria-Barbara Winter ◽  
...  

AbstractEutrophication due to increased nitrogen concentrations is known to alter species composition and threaten sensitive habitat types. The contribution of atmospheric nitrogen deposition to eutrophication is often difficult to determine. Various deposition models have been developed to estimate the amount of nitrogen deposited for both entire regions and different landscape surface types. The question arises whether the resulting deposition maps allow direct conclusions about the risk of eutrophication-related changes in the understory vegetation composition and diversity in nitrogen-sensitive forest ecosystems. We combined vegetation and soil data recorded across eutrophication gradients in ten oligo-mesotrophic forest types in southwest Germany with datasets from two different deposition models specifically fitted for forests in our study region. Altogether, 153 forest stands, with three sampling replicates each, were examined. Linear mixed-effect models and NMDS analyses revealed that other site factors, in particular the soil C/N ratio, soil pH and canopy cover, played a greater role in explaining vegetation gradients than nitrogen deposition. The latter only rarely had effects on species richness (positive), nitrophyte cover (positive or negative) and the cover of sensitive character species (negative). These effects varied depending on the deposition model used and the forest types examined. No effects of nitrogen deposition on average Ellenberg N values were found. The results reflect the complex situation in forests where nitrogen availability is not only influenced by deposition but also by nitrogen mineralization and retention which depend on soil type, pH and (micro)climate. This context dependency must be regarded when evaluating the effects of nitrogen deposition.


1999 ◽  
Vol 29 (4) ◽  
pp. 487-496 ◽  
Author(s):  
Roger G Sayre ◽  
Timothy J Fahey

The effects of acid rain and ozone on the leaching of chemicals from the canopy of red spruce (Picea rubens Sarg.) saplings was measured over a 4-year treatment period. The saplings were exposed to various levels of ozone and to acid rain (pH 3.1, 4.1, and 5.1) using open-top chambers. No effects of ozone treatments on canopy leaching were observed. Significant effects of rainfall pH on canopy leaching of Ca2+ and Mg2+ were observed, and post-hoc analysis indicated that these effects were associated only with the most acidic treatment (pH 3.1). In the low pH treatment (high NO3- and SO42-) significant canopy retention of both NO3- and SO42- were observed. The observed increase in base cation leaching flux from the red spruce canopy in the low pH treatment was particularly prominent early in the growing season (June) probably reflecting incomplete cuticle formation in the young foliage. Although the annual magnitude of extra Ca2+ leaching from the canopy of red spruce trees in the low pH treatment was small relative to the foliar calcium pool (about 10%), if this leaching preferentially depletes a physiologically important pool, it may influence tree health.


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