Light threshold for optimal black spruce (Piceamariana) seedling growth and development under brush competition

1994 ◽  
Vol 24 (8) ◽  
pp. 1629-1635 ◽  
Author(s):  
Robert Jobidon

Light threshold is suggested as a method for quantifying brush competition in black spruce (Piceamariana (Mill.) B.S.P) plantations and predicting losses in tree growth as measured by the relative growth rate (RGR). The severity of the competing vegetation (expressed in terms of density and height) around 300 planted tree seedlings, and the growth status of the seedlings (expressed in terms of total height and current height growth increment), were analyzed simultaneously with multivariate analysis of variance (MANOVA), with one level of light quantity (photosynthetically active radiation) reaching the upper one-half of the tree seedlings as the predictor variable. This study showed that it is possible to establish a competitive status based on light interception, thus allowing a grouping of seedlings with similar growth characteristics and severity of competition. Canonical analysis showed that 60% of full sunlight reaching the upper one half of spruce seedlings can be defined as a threshold to significantly discriminate between stressed and unstressed tree seedlings, based on the above-mentioned variables and also based on spruce basal stem diameter. For spruce total height, current height increment, and basal stem diameter, significant differences were found between plots above and below this threshold, averaging 18.5, 44.7, and 23.2%, respectively. Measuring the intensity of light reaching the upper one half of the spruce seedlings also significantly explains spruce relative growth rates, expressed in terms of height growth increment and basal stem diameter growth increment over the following two growing seasons. The light threshold used in the MANOVA and the ANOVA showed significant differences between plots above and below the threshold, averaging 70 and 58% for spruce height and basal stem diameter RGRs, respectively. Instead of measuring competing vegetation variables and relative height of a crop species to infer light interception, this study demonstrated that a direct measure of light attenuation at the tree seedling level can be used to assess the competitive status and predict losses in tree growth for the period of time required by the seedlings to emerge from the vegetation cover. Moreover, this study demonstrated that canonical relations, rather than linear relations, explain the pattern of competition for light between young spruce seedlings and brushlike vegetation. The light threshold suggested in this study has potential for assessing interspecific competition problems in young black spruce plantations and is proposed as a tool to support a containment strategy of vegetation management.

1991 ◽  
Vol 21 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Robert Jobidon

Bialaphos foliar sprays were tested in eastern Quebec for control of red raspberry (Rubusidaeus L.), and the tolerance of planted black spruce (Piceamariana (Mill.) B.S.P.) seedlings was determined. Approximately 3 weeks after bialaphos was applied in July, August, or September, virtually all raspberry plants were killed. Efficiency of the June application, however, was much reduced. Spruce current-year foliage was more affected than older foliage. Foliar injury was more pronounced for bialaphos applications in June and July than for applications in August. First-year spruce survival was not affected by the treatments. Second-year evaluations revealed a significant quadratic relation of (i) month of application × bialaphos rate on raspberry density and (ii) bialaphos rate on raspberry height growth. Reduction in raspberry density and height growth was greater with the 2.0 and 2.5 kg active ingredient per hectare rates applied in August. As part of the evaluation of treatment efficiency, photosynthetically active radiation reaching spruce seedlings was measured using a portable integrating radiometer. Raspberry density and height growth were both negatively correlated with photosynthetically active radiation reaching spruce seedlings. A significant quadratic relation was found between bialaphos rate and 2nd-year spruce survival, which reached 95%, regardless of month and rate of application. A significant quadratic relation was found between spruce diameter growth increment and bialaphos rate. Except for calcium, 2nd-year spruce foliar mineral content was not affected by the treatments. Bialaphos treatments in August, with rates ranging from 1.0 to 2.0 kg active ingredient per hectare, had only slight or no adverse effects on spruce survival, foliar injury, and growth increment. Selective control of red raspberry in young black spruce plantations is a function of bialaphos rate and month of application.


1999 ◽  
Vol 29 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Raynald Paquin ◽  
Hank A Margolis ◽  
René Doucet ◽  
Marie R Coyea

Growth and physiology of layers versus naturally established seedlings of boreal black spruce (Picea mariana (Mill.) BSP) were compared 15 years after a cutover in Quebec. During the first 8 years, height growth of seedlings was greater than that of layers, averaging 10.4 and 7.0 cm/year, respectively. For the last 5 years, annual height growth of layers and seedlings did not differ (25 cm/year; p > 0.05). Over the entire 15-year period, total height growth of seedlings (251 cm) was greater than that of layers (220 cm), although total height did not differ (p > 0.05) over the last 6 years. During the 15th growing season, there were no differences (p > 0.05) for predawn shoot water potential, stomatal conductance, net photosynthesis, intercellular to ambient CO2 ratio, water use efficiency, and hydraulic conductance between layers and seedlings. For diurnal shoot water potential, seedlings showed slightly less stress than layers on two of the four sampling dates. Thus, in the first few years following the cutover, the slower growth observed for layers indicated that they had a longer acclimation period following the cutover. Afterwards, similar height growth, total height, and physiological characteristics of the two regeneration types indicated that layers can perform as well as naturally established seedlings.


2002 ◽  
Vol 32 (9) ◽  
pp. 1585-1596 ◽  
Author(s):  
Sylvain Jutras ◽  
Jean Bégin ◽  
André P Plamondon

The objective of this study was to retrospectively evaluate, with the help of stem analysis, the growth increases of natural and planted black spruce (Picea mariana (Mill.) BSP) seedlings in 39 drainage networks located in Quebec public boreal forest and drained operationally after cutting. The ecological conditions of the sites have been described using the forest ecosystem classification for the Clay Belt of eastern Ontario. A significant effect of the drainage on 9-year periodic growth in diameter and height of natural black spruce seedlings, varying with distance from the ditch and ecological conditions, was observed. Stocking of natural black spruce seedlings was sufficient to insure the reconstruction of a forest stand both on the treated sites and on the control sites. The 5-year height growth increment of planted black spruce seedlings was weaker than that of the natural seedlings, which were located on the same sites, and it varied with distance from the ditches.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jakub Kašpar ◽  
Pavel Šamonil ◽  
Martin Krůček ◽  
Ivana Vašíčková ◽  
Pavel Daněk

The height growth of the trees depends on sufficient mechanical support given by the stem and an effective hydraulic system. On unstable slopes, tree growth is affected by soil pressure from above and potential soil erosion from below the position of tree. The necessary stabilization is then provided by the production of mechanically stronger wood of reduced hydraulic conductivity. Unfortunately, the interaction between tree growth (both radial and axial) and stabilization in the soil is still insufficiently understood. Therefore, in this study, we aimed to quantify the impact of hillslope dynamics on the degree of tree growth and hydraulic limitation, and the potential effect on tree height growth and growth plasticity. To evaluate this effect, we took four cores from 80 individuals of Quercus robur and Fraxinus excelsior and measured tree-ring widths (TRWs) and vessel lumen areas (VLAs). The tree heights were evaluated using a terrestrial laser scanner, and local soil depth was measured by a soil auger. Our data showed a significant limitation of the tree hydraulic system related with the formation of eccentric tree-rings. The stem eccentricity decreased with increasing stem diameter, but at the same time, the negative effect of stem eccentricity on conduit size increased with the increasing stem diameter. Even though this anatomical adaptation associated with the effect of stem eccentricity differed between the tree species (mainly in the different degree of limitations in conduit size), the trees showed an increase in the proportion of hydraulically inactive wood elements and a lowered effectiveness of their hydraulic system. In addition, we observed a larger negative effect of stem eccentricity on VLA in Quercus. We conclude that the stabilization of a tree in unstable soil is accompanied by an inability to create sufficiently effective hydraulic system, resulting in severe height-growth limitation. This affects the accumulation of aboveground biomass and carbon sequestration.


2021 ◽  
Vol 483 ◽  
pp. 118908
Author(s):  
Mizanur Rahman ◽  
Masum Billah ◽  
Md Obydur Rahman ◽  
Debit Datta ◽  
Muhammad Ahsanuzzaman ◽  
...  

1978 ◽  
Vol 54 (6) ◽  
pp. 296-297 ◽  
Author(s):  
Douglas A. Mead

Height growth of eastern larch (Larix laricina (Du Roi) K. Koch) and black spruce (Picea mariana (Mill.) B.S.P.) was determined using standard stem analysis methods on trees from two sites in northwestern Ontario. The data were obtained from mixed larch-spruce stands which were relatively undisturbed. The larch exhibited substantially better height growth than the spruce through age 65.


2008 ◽  
Vol 26 (1) ◽  
pp. 35-38
Author(s):  
L. Eric Hinesley ◽  
Frank A. Blazich

Abstract Stem cuttings of Leyland cypress [Callitropsis × leylandii (A. B. Jacks. & Dallim.) D. P. Little; syn. × Cupressocyparis leylandii (A. B. Jacks. & Dallim.) Dallim. & A. B. Jacks.] were rooted beginning May 2004. In February 2005, liners were sorted into four grades [1 = firm root ball, top to bottom, 2 = good root ball, but loose in the upper one-third; 3 = no distinct root ball, but with enough roots to survive when potted and grown in irrigated containers; and 4 = roots ≤ 2 cm (0.8 in) in length (discarded)]. Liners from Grades 1 and 2 were transplanted to the field April 2005. Additional liners of Grades 1, 2, and 3 were grown in 3.8-liter (1-gal) containers in a nursery during 2005, and field planted early September 2005. Height and stem diameter were recorded after 1 and 2 years. Containerizing affected stem diameter more than height. Growth during the first 2 years was proportional to initial size, indicating the benefits of grading. After 2 years, the largest plants were Grade 1 liners that went directly to the field April 2005, with no intermediate potting.


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