Crown deterioration and reduced growth associated with excessive seed production by birch

1972 ◽  
Vol 50 (12) ◽  
pp. 2431-2437 ◽  
Author(s):  
H. L. Gross

In 1967 yellow birch, Betula alleghaniensis Britt., and white birch, B. papyrifera Marsh., developed extremely large seed crops in Ontario. Foliage was dwarfed or missing in the heavily seeded portions of tree crowns. Buds did not develop on the terminal portions of most branches, and in 1968 branches died back to the point where buds were available for growth. Terminal growth and diameter growth were reduced for both species in 1967, and terminal growth by yellow birch continued at a reduced rate in 1968. Terminal growth and bud production were inversely related to the amount of fruiting. Similar conditions prevailed on some yellow birch in 1970.Yellow birch was more seriously affected, and in most mature stands dieback averaged 20 to 50 cm. White birch was not affected to this extent; however, some trees in most mature stands suffered extensive dieback.

1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.


1999 ◽  
Vol 29 (3) ◽  
pp. 339-346 ◽  
Author(s):  
M A Arthur ◽  
T G Siccama ◽  
R D Yanai

Improving estimates of the nutrient content of boles in forest ecosystems requires more information on how the chemistry of wood varies with characteristics of the tree and site. We examined Ca and Mg concentrations in wood at the Hubbard Brook Experimental Forest. Species examined were the dominant tree species of the northern hardwood forest and the spruce-fir forest. The concentrations of Ca and Mg, respectively, in lightwood of these species, mass weighted by elevation, were 661 and 145 µg/g for sugar maple (Acer saccharum Marsh.), 664 and 140 µg/g for American beech (Fagus grandifolia Ehrh.), 515 and 93 µg/g for yellow birch (Betula alleghaniensis Britt.), 525 and 70 µg/g for red spruce (Picea rubens Sarg.), 555 and 118 µg/g for balsam fir (Abies balsamea (L.) Mill.), and 393 and 101 µg/g for white birch (Betula papyrifera Marsh.). There were significant patterns in Ca and Mg concentrations with wood age. The size of the tree was not an important source of variation. Beech showed significantly greater concentrations of both Ca (30%) and Mg (33%) in trees growing in moist sites relative to drier sites; sugar maple and yellow birch were less sensitive to mesotopography. In addition to species differences in lightwood chemistry, Ca and Mg concentrations in wood decreased with increasing elevation, coinciding with a pattern of decreasing Ca and Mg in the forest floor. Differences in Ca and Mg concentration in lightwood accounted for by elevation ranged from 12 to 23% for Ca and 16 to 30% for Mg for the three northern hardwood species. At the ecosystem scale, the magnitude of the elevational effect on lightwood chemistry, weighted by species, amounts to 18% of lightwood Ca in the watershed and 24% of lightwood Mg but only 2% of aboveground biomass Ca and 7% of aboveground Mg.


1976 ◽  
Vol 13 (1) ◽  
pp. 145-156 ◽  
Author(s):  
Pierre Richard ◽  
Philippe Poulin

The history of vegetation has been registered in the sediments of lake Mimi since about 11 000 BP, The initial vegetation traced is a tundra which, under severe climatic conditions, lasted for about 1000 years. The herb tundra was progressively replaced by shrub tundra: a willow phase (Salix). followed by a dwarf birch phase (Betula cf. glandulosa) have been traced. These were followed by an afforestation phase characterized by an aspen community (Populus tremuloides) al about 10 000 BP. Spruce succeeded the aspen community, probably as an open black spruce (Picea mariana) community with some dwarf birch and green alder (Alnus crispa). An outstanding Alnus cf. crispa pollen peak (48%), supported by the annual pollen influx values, at the end of the spruce phase, could be interpreted as a return of colder climate that favored the expansion of this shrub over forest. This event would date about 9750 BP. An open fir (Abies balsamea) forest followed, and changed to the balsam fir – white birch (Betula papyrifera) forest (climax domain), which prevailed until now. The richer sites supported sugar maple (Acer saccharum) – yellow birch (Betula alleghaniensis) community and fir – yellow birch stands since 6200 BP. Six radiocarbon dates and annual pollen influx values are offered, and some ecological problems related to the interpretation of the pollen diagram are discussed.


1997 ◽  
Vol 73 (6) ◽  
pp. 702-710 ◽  
Author(s):  
Louis Archambault ◽  
Jacques Morissette ◽  
Michèle Bernier-Cardou

Forest successions following a forest fire that occurred in 1932 were studied on mesic sites of the boreal mixedwood forest of the Bas-Saint-Laurent region of Quebec, Canada. Physiographic, soil and vegetation data were collected in 28 ecosystems distributed on a topographic gradient. The vegetation composition of the main canopy, 64 years after the fire, varied according to topographic situation. The proportion of tolerant hardwood species (yellow birch (Betula alleghaniensis Britton), sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.)) increased toward upper slopes whereas it was the opposite for coniferous species (white spruce (Picea glauca [Moench] Voss), balsam fir (Abies balsamea [L.] Mill.)), as their proportion increased toward lower slopes. Intolerant hardwood species (white birch (Betula papyrifera Marsh.), trembling aspen (Populus tremuloides Michx.)) were abundant in all ecosystems. The distribution pattern of regeneration density and stocking of tolerant hardwoods and conifers was similar to that of the main canopy. The majority of commercial species, including tolerant species, established rapidly after the fire. Only eastern white cedar (Thuya occidentalis L.), which is a species typical of late succession, did not grow back. Ten years after the fire, 78% of the sampled dominant trees were established. Competition caused by mountain maple (Acer spicatum Lam.) did not seem to be as important after fire compared with the situation after clearcutting. Results showed that after the elimination of intolerant species, the vegetation composition should evolve toward the potential vegetation (climax) of the toposequence, that is, the sugar maple - yellow birch type on upper slopes, the balsam fir - yellow birch type on midslopes and the balsam fir - yellow birch - cedar type on lower slopes. Key words: succession, fire, yellow birch, balsam fir, mountain maple.


1970 ◽  
Vol 48 (9) ◽  
pp. 1525-1540 ◽  
Author(s):  
Ruth Horner Arnold

Disease symptoms found in nature on yellow birch (Betula alleghaniensis Britt.) infected by Diaporthe alleghaniensis R. H. Arnold, were induced by inoculation of seedlings and saplings with mycelium or conidia. On vigorously growing yellow birch plants, cankers, dead shoots, blackened necrotic petioles and mid-veins of leaves, and leaf spot developed during the inoculation year, and dieback occurred the next spring. Spore tendrils of the Phomopsis state of the pathogen were found on the most recently killed parts of the plants from May until early July. Initial symptoms were most severe on young tissues, and inoculation of shoots caused more damage to seedlings than inoculation of older tissues. The pathogen persisted in the host for several years without symptom expression, or in healed-over cankers. Initial symptoms were more severe on unshaded than on shaded seedlings, but shading increased the ultimate severity of the disease. Soil temperature and soil moisture did not influence artificial infection and subsequent development of the disease. There was evidence that the fungus produces a wilt-inducing agent. The disease was not found in nature on white birch (Betula papyrifera Marsh.), but seedlings were infected artificially. The probable course and importance of natural infection of yellow birch is discussed.


Author(s):  
Svein Dale

AbstractIn boreal forests, food supplies typically have cyclic variations, and many species here fluctuate in numbers from year to year. One group of species showing large variations in population size is birds specialized on seeds from masting trees. Here, I analyze spatial patterns of a mass occurrence and habitat selection of the Common Redpoll (Carduelis flammea) during the breeding season in southeastern Norway in 2020 after a year with large seed crops from Norway Spruce (Picea abies) and Downy Birch (Betula pubescens). I found that Common Redpoll numbers increased with elevation and towards the northwest. Numbers were also strongly and positively correlated with snow depth in early April when snow was present mainly above 400 m elevation. Sites with snow cover in early April (30% of all sites) held 96.4% of all individuals recorded. Field observations indicated that Common Redpolls foraged extensively for spruce seeds on the snow until the end of May when young were independent. I suggest that the mass occurrence was due to a unique combination of exceptionally large seed crops of two tree species coinciding in the same year. The masting produced large amounts of food both for overwintering (birch seeds) and for breeding (spruce seeds), and during the breeding season snow cover facilitated access to food resources. Dependency of Common Redpolls on snow cover suggests that climate change may negatively impact some seed-eaters in boreal regions. On the other hand, higher temperatures may induce more frequent masting which may be beneficial for seed-eaters. Thus, climate change is likely to lead to complex ecosystem changes in areas where snow cover may disappear.


1985 ◽  
Vol 61 (3) ◽  
pp. 229-232 ◽  
Author(s):  
Jean-Louis Boivin

Clearcutting of 20, 40 and 60 m wide strips was done in 1970 in Malakoff township, in the lower part of the Dumoine river watershed. A regeneration study took place in 1984.Analysis of results shows that the strips are well regenerated. The proportion of yellow birch grows with the width of the strips, that is, from 20 to60 m. To this effect strips of 60 m seem to be better for regenerating yellow birch but the future of this species seems to be better ensured in 40-m-wide strips.Yellow birch and sugar maple constitute the main part of the actual stands. If treatment is done and if observed trends persist, yellow birch should account for 21, 26 and 44% of the stems in mature stands of the 20-, 40- and 60-m strips respectively. With treatment, the presence of yellow birch could be increased to nearly 48%.


1975 ◽  
Vol 8 (5) ◽  
pp. 284-289

Sugar beet differs from most other farm seed crops, in that “varieties” are mixtures of hybrids from a blend of genotypes. Growing and processing are two equally important aspects of seed production. In this article, cultural and harvesting methods are described, and processing and marketing procedures are briefly outlined. The impact of EEC regulations affecting seeds is also considered.


1987 ◽  
Vol 17 (3) ◽  
pp. 263-266 ◽  
Author(s):  
A. R. C. Jones ◽  
I. Alli

During the spring of 1984 and 1985, white birch (Betulapapyrifera Marsh), sweet birch (B. lenta L), and yellow birch (B. alleghaniensis Britt.) were tapped to determine sap yields and syrup characteristics. These properties were compared with sap yields and syrup produced from sugar maple (Acersaccharum Marsh) and red maple (A. rubrum L). The sap flow seasons were as follows: white birch, 23 days (April 7–29, 1984) and 29 days (April 5 – May 3, 1985); sweet birch, 26 days (1984); yellow birch, 25 days (1985). The sap flow season for the maple species was much earlier than the birch species. Maple sap flow seasons were as follows: sugar maple, 16 days (March 28 – April 12, 1984) and 45 days (March 10 – April 23, 1985); red maple, 44 days (March 11 – April 23, 1985). Sap yields were as follows: white birch, 80.5 L in 1984 (1.0% sap) 51.0 L in 1985 (1.0% sap); sweet birch, 48.0 L in 1984 (0.5% sap); yellow birch, 28.4 L in 1985 (0.5% sap); red maple, 30.6 L in 1985 (2.3% sap); sugar maple, 53.5 L in 1985 (4.5% sap). Sap analyses showed the average total carbohydrate content of all birch saps and all maple saps was 9.2 and 24.5 g/L, respectively. The average sugar contents of the syrups from the birch saps and the maple saps were 302 and 711 g/L, respectively. The average pH of birch and maple saps were similar but the average pH of the syrups obtained from the birch saps was substantially lower than that of the syrups obtained from the maple saps.


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