Spatiotemporal variation in black spruce cone and seed crops along a boreal forest - tree line transect

2000 ◽  
Vol 30 (6) ◽  
pp. 900-909 ◽  
Author(s):  
Luc Sirois
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
Forest Tree ◽  
Line Transect ◽  
Tree Line ◽  
Cone Production ◽  
Forest Sites ◽  
Seed Crops ◽  
The Relationship ◽  
Filled Seeds

To assess the relationship between the regenerative potential of black spruce (Picea mariana (Mill.) BSP) and the latitudinal and thermal gradients, the cone crop was monitored in the same selection of trees during the 1989-1995 period in the northern boreal forest (sites A, n = 49, and B, n = 48), in the southern forest-tundra transition zone (site C, n = 35), and at the tree line (site D, n = 21). The size of the cone crop, the amount of seeds extracted per cone, along with the percentages of filled seed and germination were measured on each tree. There was no south to north trend associated with the cone crop. The cone crop at tree line was not significantly lower than in either of the southerly sites in six of the seven observed years. The number of seeds extracted per cone, the percentage of filled seeds, and the germination of filled seeds showed significant decrease northward according to year. Although there was no significant relationship between temperature and the cone production over the study area, the percentages of filled seeds and germination were significantly (0.51 [Formula: see text] r2 [Formula: see text] 0.44; p < 0.001) associated with the regional variation in heat sum.

Summary and Synthesis: Past and Future Changes in the Alaskan Boreal Forest

2006 ◽  
Author(s):  
Marilyn W. Walker ◽  
Mary E. Edwards
Keyword(s):  
Boreal Forest ◽  
Bark Beetles ◽  
Fire Regime ◽  
Black Spruce ◽  
Rapid Change ◽  
White Spruce ◽  
Late Glacial ◽  
Fire Frequency ◽  
Tree Resistance ◽  
Forest Sites

Historically the boreal forest has experienced major changes, and it remains a highly dynamic biome today. During cold phases of Quaternary climate cycles, forests were virtually absent from Alaska, and since the postglacial re-establishment of forests ca 13,000 years ago, there have been periods of both relative stability and rapid change (Chapter 5). Today, the Alaskan boreal forest appears to be on the brink of further significant change in composition and function triggered by recent changes that include climatic warming (Chapter 4). In this chapter, we summarize the major conclusions from earlier chapters as a basis for anticipating future trends. Alaska warmed rapidly at the end of the last glacial period, ca 15,000–13,000 years ago. Broadly speaking, climate was warmest and driest in the late glacial and early Holocene; subsequently, moisture increased, and the climate gradually cooled. These changes were associated with shifts in vegetation dominance from deciduous woodland and shrubland to white spruce and then to black spruce. The establishment of stands of fire-prone black spruce over large areas of the boreal forest 5000–6000 years ago is linked to an apparent increase in fire frequency, despite the climatic trend to cooler and moister conditions. This suggests that long-term features of the Holocene fire regime are more strongly driven by vegetation characteristics than directly by climate (Chapter 5). White spruce forests show decreased growth in response to recent warming, because warming-induced drought stress is more limiting to growth than is temperature per se (Chapters 5, 11). If these environmental controls persist, projections suggest that continued climate warming will lead to zero net annual growth and perhaps the movement of white spruce to cooler upland forest sites before the end of the twenty-first century. At the southern limit of the Alaskan boreal forest, spruce bark beetle outbreaks have decimated extensive areas of spruce forest, because warmer temperatures have reduced tree resistance to bark beetles and shortened the life cycle of the beetle from two years to one, shifting the tree-beetle interaction in favor of the insect (Chapter 9).

Landscape-level variability in the age underestimation of understory black spruce in the northern boreal forest of Quebec

2005 ◽  
Vol 35 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Marc-André Parisien ◽  
Luc Sirois ◽  
Sylvain Parent
Keyword(s):  
Boreal Forest ◽  
Mixed Models ◽  
Black Spruce ◽  
Ground Level ◽  
Simple Linear Regression ◽  
Linear Regression Models ◽  
Growth Rings ◽  
Age Correction ◽  
The Relationship ◽  
Landscape Level

This study examines the variability of the potential aging error for saplings (height ≤1.5 m) of black spruce (Picea mariana (Mill.) B.S.P.) in mature fire-dominated stands (n = 14 stands) of the northern boreal forest of northwestern Quebec. Age underestimation was determined by counting the number of underground bud scars of saplings. The magnitude and variability of age underestimation was compared within and among stands. The relationship between corrected ages (the sum of age underestimation and the number of growth rings at ground level) and ground-level ages was strongly linear and was therefore described with simple linear regression models. To evaluate landscape-level variability in this relationship, the regressions were compared among stands using mixed models. Despite high variability in age underestimation at the stand level, the relationship between corrected and ground-level age was highly significant (p < 0.0001) for all stands except one. However, there were many significant statistical differences between these regressions, indicating high landscape-level variability. The magnitude of age underestimation was found to be highly site specific (means of 7–26 years), the phenomenon being more marked and variable in older stands. Given high landscape-level variability, age underestimation of understory black spruce saplings in northern boreal stands must be documented for every sampled stand to apply a valid age correction in studies that involve multiple stands.

Uptake of urea by “drunken” trees on permafrost

2020 ◽  
Author(s):  
Kazumichi Fujii ◽  
Yojiro Matsuura ◽  
Yoshiyuki Inagaki ◽  
Chie Hayakawa
Keyword(s):  
Amino Acids ◽  
Boreal Forest ◽  
Black Spruce ◽  
Plant Root ◽  
Mineral Soil ◽  
The Other ◽  
N Limitation ◽  
Forest Sites ◽  
Mycorrhizal Association ◽  
Permafrost Table

&lt;p&gt;Boreal forest productivity on permafrost is limited by availability of soil nitrogen (N) in the active layer. Low soil temperature and summer flooding limit microbial N mineralization on shallow permafrost table. Uptake of amino acids by plant root-mycorrhizal association is known to mitigate N limitation in boreal forest soils. However, amino acid hypothesis can not fully explain advantage of black spruce trees in drunken forests due to competition of amino acids between plants, bryophytes, and microbes. Based on the observation of urea accumulation in deeper soil, we test another hypothesis that black spruce trees take up intact urea in deeper soil. Mixture solutions (glutamic acid, urea, ammonium, nitrate), with only one N form labeled by &lt;sup&gt;13&lt;/sup&gt;C and/or &lt;sup&gt;15&lt;/sup&gt;N, was injected into the organic/mineral soil layers. We compared two black spruce forest sites with/without shallow permafrost table in northern Canada. We found that black spruce trees take up intact urea as well as amino acids in the shallow permafrost sites. Urea accumulation is explained by low microbial activities to mineralize &lt;sup&gt;14&lt;/sup&gt;C-labeled urea. The other plants or bryophyte compete with black spruce for amino acids, but not for urea. Since the other black spruce trees in the deeper soil sites rely on amino acids and inorganic N, urea uptake strategy is specific to black spruce trees on shallow permafrost table. The root expansion on hummocky microrelief provides opportunity for leaning trees to access urea. The uptake of intact urea could be one of strategy of black spruce trees to mitigate N limitation in permafrost-affected hummocky soils.&lt;/p&gt;

scholarly journals Snag use by Foraging Black-Backed Woodpeckers (Picoides Arcticus) in a Recently Burned Eastern Boreal Forest

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Antoine Nappi ◽  
Pierre Drapeau ◽  
Jean-François Giroux ◽  
Jean-Pierre L. Savard
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Black Spruce ◽  
High Quality ◽  
Salvage Logging ◽  
Northeastern North America ◽  
Picoides Arcticus ◽  
One Year ◽  
The Relationship ◽  
Wood Boring

Abstract We studied snag use for foraging by Black-backed Woodpeckers (Picoides arcticus) one year after a fire in an eastern black spruce (Picea mariana) boreal forest in Quebec, Canada. We searched for signs of foraging (bark flaking and excavation holes) by Black-backed Woodpeckers on 6,536 snags sampled in 56 plots located in portions of the burned forest that had not been salvage logged. A logistic regression model was developed based on the presence or absence of foraging signs. Results showed that Black-backed Woodpeckers used larger snags that were less deteriorated by fire (qualified as high-quality snags). Direct field observations of individuals foraging on 119 snags also indicated that used snags corresponded to those of high predicted quality. Finally, we assessed the relationship between food availability and snag characteristics by measuring the density of wood-boring beetle larvae holes on 30 snags of different size and deterioration classes. High-quality snags contained higher prey densities (wood-boring beetle holes) than smaller and more deteriorated snags. We recommend that forest blocks characterized by large and less deteriorated trees be preserved from salvage logging in recently burned boreal forests in northeastern North America.

Age and size effects on seed productivity of northern black spruce

2013 ◽  
Vol 43 (6) ◽  
pp. 534-543 ◽  
Author(s):  
Jayme N. Viglas ◽  
Carissa D. Brown ◽  
Jill F. Johnstone
Keyword(s):  
Boreal Forest ◽  
Seed Production ◽  
Fire Regime ◽  
Black Spruce ◽  
Seed Viability ◽  
Basal Area ◽  
Yukon Territory ◽  
Stand Age ◽  
Seed Productivity ◽  
Cone Production

Slow-growing conifers of the northern boreal forest may require several decades to reach reproductive maturity, making them vulnerable to increases in disturbance frequency. Here, we examine the relationship between stand age and seed productivity of black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.) in Yukon Territory and Alaska. Black spruce trees were aged and surveyed for cone production and seed viability across 30 even-aged stands ranging from 12 to 197 years old. Logistic regression indicated that individual trees had a ∼50% probability of producing cones by age 30 years, which increased to 90% by age 100 years. Cone and seed production increased steadily with age or basal area at both the tree and stand level, with no evidence of declining seed production in trees older than 150 years. Using published seed:seedling ratios, we estimated that postfire recruitment will be limited by seed availability in stands for up to 50 years (on high-quality seedbeds) to 150 years (low-quality seedbeds) after fire. By quantifying these age and seed productivity relationships, we can improve our ability to predict the sensitivity of conifer seed production to a range of disturbance frequencies and thus anticipate changes in boreal forest resilience to altered fire regime.

The relationship between site and tree characteristics and the presence of wet heartwood in black spruce in the boreal forest of Quebec, Canada

2006 ◽  
Vol 36 (6) ◽  
pp. 1519-1526 ◽  
Author(s):  
Cornelia Krause ◽  
Réjean Gagnon
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
Significant Proportion ◽  
Organic Soil ◽  
Average Height ◽  
Groundwater Levels ◽  
Site Characteristics ◽  
Content Classification ◽  
Study Sites ◽  
The Relationship

Wet heartwood in black spruce (Picea mariana (Mill.) BSP) causes considerable problems during the drying process. Forest companies try to avoid harvesting stands with wet heartwood, but no relationship has been yet established between the incidence of wet heartwood and tree or site characteristics. To characterize areas containing a significant proportion of black spruce affected by wet heartwood, a total of 635 black spruce trees were sampled in eighteen 400 m2 study plots under management in the central boreal forest of Quebec. A total of 18 study sites were analysed and classified as wet, intermediate, or dry, based on the proportion of individuals with wet heartwood. Thirteen of the study sites were classified as wet, two as intermediate, and three as dry. The average age calculated for trees on wet sites was significantly (p = 0.0001) higher than that of the other two classes, whereas growth rate was significantly lower on wet sites. No difference was noted in the average height or diameter of the individuals from all three classes. The wet sites contained organic soil, whereas Podzols characterized two of the three dry study sites. An additional sampling of black spruce (n = 509) revealed a significant relationship between the groundwater level and heartwood moisture content classification (i.e., dry, intermediate, or wet). Trees in the dry heartwood class grew on sites with the lowest groundwater levels (p = 0.002) compared with trees in the wet or intermediate classes.

Spatiotemporal distribution of light rings in subarctic black spruce, Quebec

1991 ◽  
Vol 21 (12) ◽  
pp. 1828-1832 ◽  
Author(s):  
Ann Delwaide ◽  
Louise Filion ◽  
Serge Payette
Keyword(s):  
Spatial Distribution ◽  
Boreal Forest ◽  
Black Spruce ◽  
Hudson Bay ◽  
Tree Line ◽  
Northern Limit ◽  
The West ◽  
Forest Region ◽  
Boreal Forest Region ◽  
Light Ring

Numerous subfossil trees from the 13th, 14th, and 15th centuries sampled in the Rivière Boniface area (east of Hudson Bay) made it possible to extend to A.D. 1221 a previously published light-ring chronology. The spatial distribution of these diagnostic rings was studied along a south-north and a west–east transect in several sites extending from the northern limit of the Boreal Forest Region to the tree line. Data showed an increase in the number and frequency of light-ring years among populations along the south–north transect but little variations along the west–east transect.

Cone size and seed yield in young Piceamariana trees

1989 ◽  
Vol 19 (3) ◽  
pp. 351-358 ◽  
Author(s):  
G. E. Caron ◽  
G. R. Powell
Keyword(s):  
Seed Yield ◽  
Black Spruce ◽  
Pollen Grains ◽  
Production Potential ◽  
Cone Production ◽  
Seed Cone ◽  
Highly Correlated ◽  
Cone Potential ◽  
Pollen Cone ◽  
Filled Seeds

Black spruce (Piceamariana (Mill.) B.S.P.) cones were collected in 1980, l981, and 1982 from young trees in four plantations of different ages. Nine measures of cone size, seed yield per cone, and seed weight were determined by cone analysis, and the variation among plantations and years was assessed by analysis of variance. Relationships among the nine measures were assessed by correlation. Cone length, cone weight, total scales per cone, potential filled seeds per cone, total seeds per cone, total filled seeds per cone, and seed efficiency were all depressed in 1981, the year of poorest cone production. Potential filled-seed yield and actual filled-seed yield were highly correlated with most cone-size measures but poorly correlated with each other. Pollen availability in 1982 was assessed by trapping and by counting pollen cones. The catch of pollen grains was positively correlated with the numbers of pollen cones per tree. Total filled seeds per cone in 1982 was strongly related to pollen availability. Seed efficiencies of less than 35%, which occurred in the younger plantations and in the year of poorest pollen-cone and seed-cone production (1981), indicated excessive loss of potential seed.

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