The Importance of Cover on Use of Conifer Plantations by Snowshoe Hares in Northern New Brunswick

1986 ◽  
Vol 62 (3) ◽  
pp. 159-163 ◽  
Author(s):  
G. R. Parker

Five conifer plantations were sampled in northern New Brunswick for winter use by snowshoe hare (Lepus americanus). In 8-year old plantations winter hare pellets were 20 times more abundant in a jack pine (Pinus banksiana) than in a black spruce (Picea mariana) stand, which in turn contained 30% more pellets than a red pine (Pinus resinosa) stand. In two 13-year-old plantations, hare pellets were more abundant in a black spruce than a jack pine stand. Conifer cover 1-3 m in height influenced pellet densities. Conifer cover < 1 m in height did not influence pellet densities (winter hare use) probably due to snow depths of approximately that height. Winter pellet densities did not relate to availability of deciduous twigs (preferred food). In young plantations (~8 years), conifer cover was greatest in jack pine stands. By 13 years, high hare densities and subsequent browsing reduced critical conifer cover values in jack pine stands. Conifer cover values and hare densities increased with age of spruce plantations due to less browsing intensity in earlier years. It is concluded that conifer cover 1-3 m above ground is the single most important factor influencing distribution of hares among spruce and pine plantations (and consequent feeding damage to stock species) during winter in northern New Brunswick. Key words: Snowshoe hare, New Brunswick, winter use of pine and spruce plantations, importance of cover.

2009 ◽  
Vol 85 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Xiangdong Lei ◽  
Changhui Peng ◽  
Haiyan Wang ◽  
Xiaolu Zhou

Historically, height–diameter models have mainly been developed for mature trees; consequently, few height–diameter models have been calibrated for young forest stands. In order to develop equations predicting the height of trees with small diameters, 46 individual height–diameter models were fitted and tested in young black spruce (Picea mariana) and jack pine (Pinus banksiana) plantations between the ages of 4 to 8 years, measured from 182 plots in New Brunswick, Canada. The models were divided into 2 groups: a diameter group and a second group applying both diameter and additional stand- or tree-level variables (composite models). There was little difference in predicting tree height among the former models (Group I) while the latter models (Group II) generally provided better prediction. Based on goodness of fit (R2and MSE), prediction ability (the bias and its associated prediction and tolerance intervals in absolute and relative terms), and ease of application, 2 Group II models were recommended for predicting individual tree heights within young black spruce and jack pine forest stands. Mean stand height was required for application of these models. The resultant tolerance intervals indicated that most errors (95%) associated with height predictions would be within the following limits (a 95% confidence level): [-0.54 m, 0.54 m] or [-14.7%, 15.9%] for black spruce and [-0.77 m, 0.77 m] or [-17.1%, 18.6%] for jack pine. The recommended models are statistically reliable for growth and yield applications, regeneration assessment and management planning. Key words: composite model, linear model, model calibration, model validation, prediction interval, tolerance interval


2001 ◽  
Vol 18 (4) ◽  
pp. 101-109 ◽  
Author(s):  
Nathan W. Siegert ◽  
Deborah G. McCullough

Abstract The exotic pine shoot beetle, Tomicus piniperda [L.] (Coleoptera: Scolytidae) is a Eurasian pest of pines that was first discovered in North America in 1992 near Cleveland, Ohio. It has since been found in at least 72 counties in Michigan, 285 additional counties in 11 other north central and eastern states, and the provinces of Ontario and Quebec. We counted injured shoots along linear transects in ten stands of Scotch (Pinus sylvestris L.), red (Pinus resinosa Aiton), and jack pine (Pinus banksiana Lambert) in lower Michigan (30 stands total) to estimate the frequency of shoot damage attributable to pine shoot beetle, other shoot-feeding insects, weather, and other damaging agents from 1997 to 1999. Fifteen of the stands were located in southwestern counties where pine shoot beetle has been established for at least 8 to 10 yr. The other 15 stands were in northern counties where pine shoot beetle establishment is more recent. In the southwestern stands, pine shoot beetle killed significantly more shoots in Scotch pine stands than in red or jack pine stands, and injured more shoots in Scotch pine stands than all other insects combined. Two of these Scotch pine stands were near an area with an abundance of Scotch pine brood material available to parent beetles. Damage in these two stands averaged roughly 10 to 12 shoots per m2 in 1998 and 1999, compared with 0.6 to 1.6 shoots per m2 in other Scotch pine stands, and less than 0.2 shoots per m2 in nearby red or jack pine stands. Pine shoot beetle was at very low or undetectable levels in northern stands in all years. Shoots injured by three other shoot-feeding insects were occasionally encountered, most often in red pine stands, but caused an insignificant amount of damage. With the exception of the southwestern Scotch pine stands, most of the shoot damage, particularly in northern jack pine stands, was attributable to squirrels or abiotic factors such as wind, ice or snow. North. J. Appl. For. 18(4):101–109.


2004 ◽  
Vol 80 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Bryce McInnis ◽  
Kathleen Tosh

The New Brunswick Tree Improvement Council analyzed 20-year data from plantations of unimproved and first generation improved black spruce (Picea mariana [Mill.] BSP) and jack pine (Pinus banksiana Lamb.). STAMAN, a computer model, conservatively projected an 11% merchantable volume gain at 40 years based on 20-year measurements of 36 000 trees. At age 20 years, first generation black spruce was 12% taller and 25–30% greater in total volume. Projections from over 160 000 individual measurements of height from age five to 20 years indicate that by 40 years, gains of 7–8% in height and 18–20% in total volume are likely. Ten year assessments from over 10 000 measurements of second generation black spruce indicate a 30% height gain over first generation material of the same age. For jack pine first generation material, the projections indicated a height gain of 14% and a total volume gain of over 30% at 40 years. Faster growth can provide greater volume at rotation age, a shorter rotation interval, or earlier interventions for commercial thinning. Key words: genetic gain, tree improvement, black spruce, jack pine


1997 ◽  
Vol 75 (2) ◽  
pp. 332-335 ◽  
Author(s):  
Michael A. Setterington ◽  
Daniel M. Keppie

Relationships between external cone characteristics (length, width, wet and dry mass), cone quality (total seed mass as a proportion of cone mass, total number of seeds per cone, total seed mass per cone), and number of cones in caches were evaluated for caches of jack pine (Pinus banksiana) cones belonging to red squirrels (Tamiasciurus hudsonicus) in two plantations in southern New Brunswick. Cone length and mass were good predictors of the total number of seeds per cone and total seed mass per cone. Length accounted for a small proportion of the variance of total seed mass as a proportion of cone mass. There was no relationship between the number of seeds or total seed mass per cone and the number of cones per cache.


1987 ◽  
Vol 63 (6) ◽  
pp. 446-450 ◽  
Author(s):  
James E. Wood ◽  
Richard Raper

In the alternate strip clearcutting system, first-cut strips are regenerated by seed produced by black spruce (Picea mariana [Mill.] B.S.P.) in the forested leave strips. However, after the second cut, such a seed source is not available for regenerating the leave strips. Therefore, the forest manager must consider a number of alternative regeneration options. The selection of the most appropriate regeneration option is dependent upon several economic and biological criteria. These include future costs of delivered wood, site productivity, post-harvest site condition, future alternative sources of supply, and future demand for industrial wood. Regeneration options such as preservation of advance growth and direct seeding are recommended for sites on which the manager is concerned primarily with regenerating first cut strips and is willing to accept a lower level of stocking in leave strips. Planting, the most intensive option discussed, should be reserved for sites offering the highest potential return or greatest future cost savings. Direct seeding of jack pine (Pinus banksiana Lamb.) should be considered on the upland portions of this patterned site type. Mixing jack pine and black spruce is a suggested regeneration option if the site contains both upland and lowland topographic positions. Other seeding options include the use of semi-transparent plastic seed shelters. The manager might consider combining two or more of these options to meet management objectives.


2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.


1998 ◽  
Vol 78 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Helmut Krause

The purpose of this study was to determine whether change of forest cover had an effect on the development of the organic surface horizons, particularly on those variables that influence nutrient cycling and forest productivity. Jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.) plantations were selected from among the youngest to oldest (2–16 yr) within a 100 km2 area in southeastern New Brunswick. Natural forests were also included as benchmark sites. The forest floor and tree foliage was sampled and trees measured on 0.05-ha plots. The forest floor samples were used to determine organic mass, nutrient contents and pH. In pine plantations, organic matter accumulated rapidly during the period of exponential tree growth, but leveled off at about 45 Mg ha–1. This was within the range of benchmark sites with mixed conifer-hardwood cover. In spruce plantations, the forest floor mass ranged upward to 77 Mg ha–1. Development was strongly influenced by the nature of the previous forest. Spruce forest floors were on average more acid and had lower nutrient concentrations, particularly N and Ca. The observed differences suggest that nutrients are recycled more rapidly in the pine plantations, partly explaining the superior growth of the latter. Key words: Forest floor, Kalmia angustifolia L., Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., nutrient cycling, plantation forest


2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.


1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz

An experimental burn in conjunction with a seed-tree system was successful in regenerating jack pine (Pinus banksiana Lamb.) on a fresh to somewhat moist upland, loamy till, cutover site in central Saskatchewan. About 20 well-formed, uniformly spaced seed trees per hectare were left standing during timber harvest. The ignition of logging slash was carried out under preselected weather and fuel conditions so that favorable seedbeds and adequate seed dispersal from the seed trees were produced. Four growing seasons after burning, jack pine stocking by 4-m2 quadrats was 90% with 12 195 seedlings/ha. Aspen (Populus tremuloides Michx.), to a lesser degree black spruce (Picea mariana [Mill.] B.S.P.), and other companion tree species also regenerated with the pine. Various seedbed and regeneration characteristics as well as height growth rates are discussed. Key words: Pinus banksiana, slash burning, seed-tree system, forest regeneration, growth rates, central Saskatchewan.


2010 ◽  
Vol 40 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Xavier Cavard ◽  
Yves Bergeron ◽  
Han Y.H. Chen ◽  
David Paré

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.


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