Growth and crown morphological responses of boreal conifer seedlings and saplings with contrasting shade tolerance to a gradient of light and height

2002 ◽  
Vol 32 (3) ◽  
pp. 458-468 ◽  
Author(s):  
Yves Claveau ◽  
Christian Messier ◽  
Philip G Comeau ◽  
K Dave Coates

The effects of gradients in light levels and tree height on growth and crown attributes of six conifer species were studied in eastern and western Canada. Three conifers were studied in British Columbia (Abies lasiocarpa (Hook.) Nutt., Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm., and Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and three in Quebec (Abies balsamea (L.) Mill., Picea glauca, and Pinus banksiana Lamb.). For several growth and morphological parameters, conifers reacted strongly to both an increase in light and tree height. Significant or nearly significant interactions between light classes and height were found for height and diameter growth of most species as well as for many crown attributes for both Abies and Picea. These interactions usually indicated that growth or morphological changes occurred with increasing height from a certain light level. Within a single genus, both eastern and western tree species showed the same overall acclimation to light and height. As generally reported, Pinus species showed less variation in growth and morphological responses to light than Abies and Picea species.

2000 ◽  
Vol 76 (4) ◽  
pp. 633-642 ◽  
Author(s):  
Jean-Claude Ruel ◽  
Christian Messier ◽  
Yves Claveau ◽  
René Doucet ◽  
Phil Comeau

Regeneration of forest stands through the preservation of existing advance regeneration has gained considerable interest in various regions of North America. The effectiveness of this approach relies on the capacity of regeneration to respond positively to overstory removal. Responses of advance regeneration to release is dependent on tree characteristics and site conditions interacting with the degree of physiological shock caused by the sudden change in environmental conditions. This paper presents a review of the literature describing the relationships between morphological indicators and the advance regeneration response to canopy removal. It focuses primarily on the following species: jack pine (Pinus banksiana Lamb.), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), black spruce (Picea mariana (Mill.) B.S.P.), interior spruce (Picea glauca × engelmannii), white spruce (Picea glauca (Moench) Voss), balsam fir (Abies balsamea (L.) Mill.), and subalpine fir (Abies lasiocarpa (Hook.) Nutt). Pre-release height growth has been found to be a good indicator of post-release response for many species. Live-crown ratio also appears to be a good indicator of vigour for shade-tolerant species. The ratio of leader length to length of the longest lateral at the last whorl could serve to describe the degree of suppression before harvest for shade-tolerant species. Number of nodal and internodal branches or buds has been found to be related with vigour for many species. Logging damage has been shown to be an important determinant of seedling response to overstory removal. In contrast, height/diameter ratio has limited value for predicting response to release since it varies with site, species and other factors. No clear relationship between age, height at release and response to release could be demonstrated. This paper also suggests the use of combined indicators and critical threshold values for these indicators. Key words: advance regeneration, careful logging, vigour, clearcutting


1999 ◽  
Vol 45 (11) ◽  
pp. 914-922 ◽  
Author(s):  
A Uzunovic ◽  
D -Q Yang ◽  
P Gagné ◽  
C Breuil ◽  
L Bernier ◽  
...  

The Canadian forest products industry suffers considerable losses due to discoloration caused by sapstain fungi. Although studied for a number of years, the identity, biology, and ecology of these fungi are still only partly understood. To determine which fungi caused stain problems, a detailed survey was conducted at seven selected sawmills across Canada. In summer 1997, fresh logs and lumber were set aside in the mills 1 month prior to sampling for fungi. We excluded bark-beetle-attacked wood and our logs remained free from their attack during storage. Five commercially important softwood species, Abies balsamea (L.) Mill., Picea mariana (Mill.) B.S.P., Picea glauca (Moench) Voss, Pinus contorta Dougl., and Pinus banksiana Lamb., were included in the studies. A total of 1863 isolates were isolated from stained and adjacent areas on test wood, and were identified based on their morphological and physiological characteristics and mating compatibility to 13 different species representing five genera. The most commonly encountered genus, Ophiostoma (97%), was represented by nine species. A more diverse range of fungi was found in logs than in lumber; some species were more frequently isolated from one type of substrate and rarely (or not at all) from the other. No fungal species occurred exclusively in a particular region or wood substrate.Key words: bluestain, lumber, logs, Ophiostoma, Ceratocystis.


2010 ◽  
Vol 86 (1) ◽  
pp. 118-129 ◽  
Author(s):  
M J Waterhouse ◽  
E. C. Wallich ◽  
N. M. Daintith ◽  
H. M. Armleder

Mature lodgepole pine (Pinus contorta) forests were harvested using group selection (GS) (0.02-ha openings) and irregular group shelterwood (IGS) (0.05-ha openings) systems to maintain arboreal and terrestrial lichens in the winter range of northern woodland caribou (Rangifer tarandus caribou). Ten years after planting, lodgepole pine showed excellent survival, but were smaller in the partial cut openings compared to the clearcuts. Pine grew less in the Sub-Boreal Pine–Spruce biogeoclimatic subzone (SBPSxc) than in the Montane Spruce subzone (MSxv), and trees were smaller in the GS versus IGS treatment within the MSxv subzone. Interior spruce (Picea glauca × engelmannii) grew best in the MSxv and partial cut treatments, but was significantly affected by summer frost in the clearcuts. In an operational-scale Adaptive Management trial, openings were enlarged to 0.15 ha, and both pine and spruce showed excellent survival, minimal frost damage, and 10-year size similar to clearcut conditions. This study suggests that lodgepole pine and interior spruce can be successfully regenerated in partial cut openings with acceptable growth in gaps of 0.15 ha. Key words: caribou, group selection, interior spruce, irregular group shelterwood, light level, lodgepole pine, Montane Spruce zone, partial harvest, soil moisture, soil temperature, Sub-Boreal Pine Spruce zone, summer frost


1991 ◽  
Vol 6 (3) ◽  
pp. 64-67 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Wayne L. Martin

Abstract The incidence of meadow vole (Microtus pennsylvanicus) and brown lemming (Lemmus sibiricus) feeding damage to young plantations of lodgepole pine (Pinus contorta var. latifolia) and interior spruce (Picea glauca × Picea engelmannii) was studied in west-central British Columbia. Fifty-eight plantations were surveyed for seedling survival and stocking, and an additional 21 older plantations of lodgepole pine were surveyed for tree damage. Average survival of pine (47.7%) was significantly lower than that of spruce (56.0%). Because of mortality from vole feeding, 24 of the 58 plantations were not satisfactorily restocked. Planted trees were attacked significantly more than natural regeneration. Severely attacked plantations occurred in the spruce-subalpine fir (Abies lasiocarpa) forest type at elevations > 800 m on N to NE aspects. Susceptible plantations generally had mechanical or no site preparation with complex post-harvest debris and limited vegetation cover. West. J. Appl. For. 6(3):64-67.


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.


2001 ◽  
Vol 77 (6) ◽  
pp. 1014-1021 ◽  
Author(s):  
E. K. Morgenstern ◽  
B. S. P. Wang

Progress in reforestation is reviewed and the results of a 1999 survey of seed collection and utilization are presented. The review includes forest depletion, regeneration and seed supply for Canada for the 1960–99 period. Depletion of stocked, timber-productive land has increased from less than 2 million ha annually to just under 2.5 million ha, primarily due to an increase in harvesting from about 800 000 ha to slightly over 1 million ha in recent years, and also due to larger fires during the last decade. The depleted area amounts to 1% of the total commercial forest. Natural regeneration consistently covered more than 60% of the depleted area. Artificial regeneration (seeding and planting) has increased dramatically from 86 000 ha per year in 1965 to 513 000 ha in 1990, and has since levelled off at about 460 000 ha. The seed supply situation has also improved greatly, primarily due to tree improvement that resulted in the establishment of seed orchards, which were expanded from 364 ha in 1981 to 3008 ha in 1995. New analytical biochemical methods suggest that in orchard seed, genetic variation and diversity are maintained.The seed survey, including 36 conifer and 29 broadleaf species, indicated that 2.5 billion seeds were collected in 1999 (which was not a good seed year) and 3.9 billion seeds were sown. These 3.9 billion seeds appear to be sufficient to again restock approximately 460 000 ha per year, i.e., the same area as regenerated annually in the 1995–99 period. Improved seed treatment and sowing methods appear to have made seedling production substantially more efficient during the last 20 years. The major species sown in 1999 were: Picea mariana (35%), Picea glauca (22%), Pinus contorta (13%), and Pinus banksiana (12%). For Canada as a whole, 25% of the seed came from seed orchards, but for the Maritime Provinces, Québec, and Manitoba this percentage ranged from 60 to 90%. Orchard production is still growing: British Columbia and Québec will produce 80% of their planting stock from it during the next decade, and New Brunswick and British Columbia are already harvesting seed from second-generation orchards. It is expected that the high quality of seed obtained from seed orchards will contribute significantly to the efficiency of the reforestation program and increase the value of future forests. Key words: forest depletion, reforestation, seed orchards, seed supply


2002 ◽  
Vol 134 (3) ◽  
pp. 299-302 ◽  
Author(s):  
Kamal J.K. Gandhi ◽  
Steven J. Seybold

The pine engraver, Ips pini (Say), is broadly distributed across North America (Lanier 1972; Wood 1982; Seybold et al. 1995) with a host range that includes most species of Pinus L., and in rare cases, species of Picea A. Dietrich (both Pinaceae), within its range (Swaine 1918; Bright 1976; Wood 1982; Furniss and Carolin 1992). Ips pini has been recorded from Pinus banksiana Lamb., Pinus resinosa Ait., and Pinus strobus L. (eastern North America), and from three of four subspecies of Pinus contorta Dougl. ex Loudon [P. c. contorta, P. c. latifolia (Engelm.) Critch., and P. c. murrayana (Balf.) Critch.], Pinus coulteri D. Don, Pinus jeffreyi Balf., Pinus ponderosa Dougl. ex P. and C. Laws., and Pinus flexilis James (western North America) (Furniss and Carolin 1992; Seybold et al. 1995). Hopping (1964) reported I. pini on Picea rubens Sarg., Picea glauca (Moench) Voss, and Picea engelmannii Parry ex Engelm. The adult insect is intermediate in length relative to most Ips spp., ranging from 3.3 to 4.5 mm (Hopping 1964; Bright 1976; Wood 1982; USDA Forest Service 1985).


2006 ◽  
Vol 36 (8) ◽  
pp. 1891-1899 ◽  
Author(s):  
Yves Claveau ◽  
Philip G Comeau ◽  
Christian Messier ◽  
Colin P Kelly

We examined the growth of understory conifers, following partial or complete deciduous canopy removal, in a field study established in two regions in Canada. In central British Columbia, we studied the responses of three species (Pseudotsuga menziesii var. glauca (Beissn.) Franco, Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm., and Abies lasiocarpa (Hook.) Nutt.), and in northwestern Quebec, we studied one species (Abies balsamea (L.) Mill.). Stem and root diameter and height growth were measured 5 years before and 3 years after harvesting. Both root and stem diameter growth increased sharply following release but seedlings showed greater root growth, suggesting that in the short term, improvement in soil resource capture and transport, and presumably stability, may be more important than an increase in stem diameter and height growth. Response was strongly size dependent, which appears to reflect greater demand for soil resources as well as higher light levels and greater tree vigour before release for taller individuals. Growth ratios could not explain the faster response generally attributed to true fir species or the unusual swift response of spruces. Good prerelease vigour of spruces, presumably favoured by deciduous canopies, could explain their rapid response to release.


2020 ◽  
Vol 12 (24) ◽  
pp. 4104
Author(s):  
Andrew J. Chadwick ◽  
Tristan R. H. Goodbody ◽  
Nicholas C. Coops ◽  
Anne Hervieux ◽  
Christopher W. Bater ◽  
...  

The increasing use of unmanned aerial vehicles (UAV) and high spatial resolution imagery from associated sensors necessitates the continued advancement of efficient means of image processing to ensure these tools are utilized effectively. This is exemplified in the field of forest management, where the extraction of individual tree crown information stands to benefit operational budgets. We explored training a region-based convolutional neural network (Mask R-CNN) to automatically delineate individual tree crown (ITC) polygons in regenerating forests (14 years after harvest) using true colour red-green-blue (RGB) imagery with an average ground sampling distance (GSD) of 3 cm. We predicted ITC polygons to extract height information using canopy height models generated from digital aerial photogrammetric (DAP) point clouds. Our approach yielded an average precision of 0.98, an average recall of 0.85, and an average F1 score of 0.91 for the delineation of ITC. Remote height measurements were strongly correlated with field height measurements (r2 = 0.93, RMSE = 0.34 m). The mean difference between DAP-derived and field-collected height measurements was −0.37 m and −0.24 m for white spruce (Picea glauca) and lodgepole pine (Pinus contorta), respectively. Our results show that accurate ITC delineation in young, regenerating stands is possible with fine-spatial resolution RGB imagery and that predicted ITC can be used in combination with DAP to estimate tree height.


2011 ◽  
Vol 89 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Teresa W. Tam ◽  
Rui Liu ◽  
John T. Arnason ◽  
Anthony Krantis ◽  
William A. Staines ◽  
...  

Seventeen Cree antidiabetic medicinal plants were studied to determine their potential to inhibit cytochrome P450 3A4 (CYP3A4) through mechanism-based inactivation (MBI). The ethanolic extracts of the medicinal plants were studied for their inhibition of CYP3A4 using the substrates testosterone and dibenzylfluorescein (DBF) in high pressure liquid chromatography (HPLC) and microtiter fluorometric assays, respectively. Using testosterone as a substrate, extracts of Alnus incana , Sarracenia purpurea , and Lycopodium clavatum were identified as potent CYP3A4 MBIs, while those from Abies balsamea , Picea mariana , Pinus banksiana , Rhododendron tomentosum , Kalmia angustifolia , and Picea glauca were identified as less potent inactivators. Not unexpectedly, the other substrate, DBF, showed a different profile of inhibition. Only A. balsamea was identified as a CYP3A4 MBI using DBF. Abies balsamea displayed both NADPH- and time-dependence of CYP3A4 inhibition using both substrates. Overall, several of the medicinal plants may markedly deplete CYP3A4 through MBI and, consequently, decrease the metabolism of CYP3A4 substrates including numerous medications used by diabetics.


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