scholarly journals Vegetation Management Using Polyethylene Mulch Mats and Glyphosate Herbicide in a Coastal British Columbia Hybrid Poplar Plantation: Four-Year Growth Response

2001 ◽  
Vol 16 (1) ◽  
pp. 26-30 ◽  
Author(s):  
K.D. Thomas ◽  
W.J. Reid ◽  
P.G. Comeau

Abstract This study was initiated in 1995 to gather information on the effectiveness of opaque polyethylene mats and glyphosate herbicide treatment on growth and yield of hybrid poplar plantations on south coastal British Columbia. Immediately after planting 40 cm tall hybrid poplar cuttings, 60 × 60 cm opaque polyethylene mats were installed. All treatment plots were mechanically cultivated in one direction twice yearly from 1995 to 1997. This practice left an uncultivated strip between trees running in the same direction as the cultivation. The uncultivated strip was approximately 1 m wide, and represented approximately one-third (0.04 ha) of the total plot area (0.13 ha). Glyphosate was applied at a rate of 2.1 kg active ingredient (ai)/ha in water to the uncultivated strips in the herbicide treatment plots in midsummer of the second and third growing seasons. The opaque polyethylene mats significantly improved poplar height growth only for the first growing season. After four growing seasons, hybrid poplars treated with glyphosate were significantly taller (983 cm) than those in either the mat (915 cm) or control treated plots (902 cm). Diameter at breast height (dbh) was also significantly greater in the herbicide treated plots (88 mm) than in either the mat (78 mm) or control (77 mm) treated plots. Total volume was also significantly greater in herbicide plots (23 ³/ha) than in either the mat (17 m³/ha) or control (17 m³/ha) plots. Basal area and total volume were 14% and 37%, respectively, greater in the herbicide plots than in the mat and control plots following the fourth growing season. West. J. Appl. For. 16(1):26–30.

1982 ◽  
Vol 60 (12) ◽  
pp. 2518-2529 ◽  
Author(s):  
Christopher Walker ◽  
Carl W. Mize ◽  
Harold S. McNabb Jr.

Two different sites in central Iowa were planted with hybrid poplars and subsequently sampled over a growing season for spores of endogonaceous fungi. At one of the sites, the effects of plowing and herbicide treatment on spore numbers also were examined. Ten species of fungi in the genera Acaulospora, Gigaspora, and Glomus were recorded at the first site. The second location yielded 12 species from the same genera. In both sites, the distribution of spores was highly variable. The poplars rarely became endomycorrhizal and had no effect on spore populations during the experimental period. Changes in spore populations were correlated with soil-moisture level. Evidence was found for some depression of spore production caused by plowing and herbicide treatment. The conclusion was drawn that small samples with but few replicates may not adequately represent populations of endogonaceous spores.


1986 ◽  
Vol 62 (3) ◽  
pp. 164-169 ◽  
Author(s):  
Edward A. Hansen

In this study I investigated the effects of planting date for soaked versus unsoaked cuttings of two hybrid poplar clones under irrigated versus unirrigated and weedy versus weed-free conditions. Cuttings were planted each year for 4 years. Survival at the end of the first growing season was generally greater than 90% for all planting dates. At the end of the second growing season survival for trees planted before July 16 was again generally more than 90%. However, cuttings planted from July 30 through August 27 showed a major decline in survival and survival of fall planted cuttings ranged from 6 to 90%. Mortality of late summer- or fall-planted cuttings occurred prior to the beginning of the second growing season and was attributed to frost heaving. The tallest trees were not those planted at the earliest possible dates (April in Rhinelander). Instead, the tallest trees at the end of the first and second growing seasons were those planted in early- and mid-May. This optimum planting period was the same regardless of clone, soaking, irrigation, or weed treatment. Actual optimum planting date would change with location and local climatic conditions. Some climatic indices may prove more universal in predicting when to plant. Although tentative, it appears that for best growth, unrooted hybrid poplar cuttings should be planted in soil warmer than 10 °C. Trees do not grow as well if planted immediately after soil frost leaves the ground. Key words: Energy plantations, plantation establishment, woody biomass, intensive culture, Populus.


2019 ◽  
Vol 49 (11) ◽  
pp. 1471-1482
Author(s):  
Woongsoon Jang ◽  
Bianca N.I. Eskelson ◽  
Louise de Montigny ◽  
Catherine A. Bealle Statland ◽  
Derek F. Sattler ◽  
...  

This study was conducted to quantify growth responses of three major commercial conifer species (lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and spruce (white spruce (Picea glauca (Moench) Voss) and hybrid spruce (Picea engelmannii Parry ex. Engelm. × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carrière))) to various fertilizer blends in interior British Columbia, Canada. Over 25 years, growth-response data were repeatedly collected across 46 installations. The fertilizer blends were classified into three groups: nitrogen only; nitrogen and sulfur combined; and nitrogen, sulfur, and boron combined. The growth responses for stand volume, basal area, and top height were calculated through absolute and relative growth rate ratios relative to a controlled group. Fertilizer blend, inverse years since fertilization, site index, stand density at fertilization, and their interactions with the fertilizer blend were used as explanatory variables. The magnitude and significance of volume and basal area growth responses to fertilization differed by species, fertilizer-blend groups, and stand-condition variables (i.e., site index and stand density). In contrast, the response in top height growth did not differ among fertilization blends, with the exception of the nitrogen and sulfur fertilizer subgroup for lodgepole pine. The models developed in this study will be incorporated into the current growth and yield fertilization module (i.e., Table Interpolation Program for Stand Yields (TIPSY)), thereby supporting guidance of fertilization applications in interior forests in British Columbia.


2005 ◽  
Vol 20 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Wayne D. Johnstone

Abstract The effects of spacing 7-year-old second-growth lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) are reported 20 growing seasons after treatment. Five spacing levels of 500, 1,000, 1,500, 2,000, and 2,500 trees per hectare, plus unspaced controls, were established on plots in central British Columbia. Both individual-tree and per-hectare data were analyzed. Spacing had a significant effect on all of the individual-tree characteristics examined, but its effect on per-hectare values was mixed. Although this report only provides short-term information on the effects of juvenile spacing on the growth and yield of lodgepole pine, it does indicate the need to optimize individual-tree growth rates with levels of growing stock to maximize yield per unit area. West. J. Appl. For. 20(3):160–166.


1999 ◽  
Vol 29 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Shannon M Hagerman ◽  
Melanie D Jones ◽  
Gary E Bradfield ◽  
M Gillespie ◽  
D M Durall

The mycelium extending from ectomycorrhizal fine roots is thought to be an important inoculum source for outplanted seedlings. The purpose of this study, carried out at a subalpine forest in British Columbia, was to investigate the effect of three different clear-cut sizes: 0.1, 1.0, and 10 ha, on the persistence and diversity of ectomycorrhizae. Over the course of the study, a total of 39 distinct mycorrhizal types were observed. The dominant types matched descriptions of E-strain mycorrhizae and of mycorrhizae formed by Cenococcum spp., two types of Lactarius spp., Piloderma spp., Hebeloma spp., Amphinema spp., and Cortinarius spp. One growing season after tree removal, there were no differences between the treatments in the numbers of active fine roots at any location nor were there any effects on the diversity of ectomycorrhizae with treatment. Two and three growing seasons after logging the persistence of some of the main morphotypes differed with treatment. Although there were no differences in the diversity indices at corresponding distances within the different opening sizes, after two and three growing seasons the numbers of active fine roots as well as the diversity of ectomycorrhizae in clearcuts was significantly reduced with distance from the forest edge.


1997 ◽  
Vol 75 (5) ◽  
pp. 799-814 ◽  
Author(s):  
Marlow G. Pellatt ◽  
Rolf W. Mathewes ◽  
Ian R. Walker

Surficial sediment samples from 42 lakes, distributed from sea level to alpine elevations of coastal British Columbia and northwest Washington, were analyzed for pollen and spores. Pollen analysis revealed characteristic differences among the assemblages of the Coastal Western Hemlock, Mountain Hemlock, and Engelmann Spruce – Subalpine Fir biogeoclimatic zones (the Alpine zone is less clearly identifiable). Cluster analysis and detrended correspondence analysis (DCA) correctly group the sites according to their biogeoclimatic zones and also by geographic origin. DCA indicates a high correlation between the biogeoclimatic zones of the sample sites and annual precipitation (−0.89), January temperature (−0.77), annual temperature (−0.64), and growing-season precipitation (−0.68). Further analysis of the samples and eight environmental gradients using canonical correspondence analysis groups the pollen assemblages from the study sites into biogeoclimatic zones in relation to annual precipitation, growing-season precipitation, annual snowfall, annual temperature, and growing degree-days. These data are useful for testing whether or not postglacial pollen assemblages have modern analogues. Key words: modern pollen analysis, vegetation, ordination, multivariate statistical analysis, biogeoclimatic zones, British Columbia.


2003 ◽  
Vol 18 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Christopher Opio ◽  
Kona van Diest ◽  
Norman Jacob

Abstract Height to diameter ratio (HDR) has been proposed as an alternative to conventional procedures for assessing competition between crop trees and other vegetation. Yet HDRs vary throughout the growing season due to variations in the rate of change in height and diameter. There is an interest, therefore, in determining variations in HDR within a growing season (intra-seasonal changes) and the time of the year when measurements of HDR should be taken for operational purposes. HDR measurements were taken on five occasions at two lodgepole pine (Pinus contorta var. latifolia) sites in the central interior of British Columbia, from early May to late October through the 1999 growing season. Although the focus of the article is the investigation of intra-seasonal changes in HDR, we also compared August 1999 measurements with August 1998 measurements to determine the variation in HDR between growing seasons (inter-seasonal change). The study involved a completely randomized, one-factor experimental design, with replication over time. The removal of competing vegetation (known as brushing) was the factor. The design consisted of four levels of brushing, replicated three times on each study site. The results indicated that HDRs increased from early May to July and then decreased until October to levels equal to or lower than those obtained in August 1998. The highest HDR values were observed in control plots. The analysis of variance (ANOVA) with repeated measures indicated that treatment (brushing radius) and date of HDR measurement had significant (P < 0.05) effects on the intra-seasonal changes in HDR. The results suggest that HDR measurements should be taken either after mid-August, or before mid-May when changes in HDR are negligible. West. J. Appl. For.18(1):52–59.


1986 ◽  
Vol 16 (1) ◽  
pp. 36-41 ◽  
Author(s):  
R. E. Carter ◽  
A. M. Scagel ◽  
K. Klinka

Nutritional problems, deficiencies of B and Zn in particular, have been tentatively identified as the cause of specific distorted growth symptoms in several young stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and Pacific silver fir (Abiesamabilis (Dougl.) Forbes) in southwestern coastal British Columbia. The most common symptoms associated with these apparent micronutrient deficiencies include leader dieback and discolouration, multileadered and bushy crowns, and, in severely deficient trees, swollen and distorted stems. Visual symptoms of apparent B deficiency become obvious when foliar concentrations are <5.0 ppm; visual symptoms of apparent Zn deficiency are less easily recognized, usually occurring when foliar Zn levels are less than approximately 9.0 ppm. Low foliar concentrations of B were often associated with low levels of Ca and Mg. Foliar B concentration was also correlated with total foliar S. Temporal variation in foliar nutrient levels, examined over 3 years, was quite high with an apparent strong relationship to growing season precipitation. This suggests that deficiencies of B and (or) Zn may be acute rather than chronic, with the appearance of periodic acute deficiencies being influenced by growing season soil moisture supply.


2019 ◽  
Vol 95 (03) ◽  
pp. 207-221 ◽  
Author(s):  
Cindy Prescott ◽  
Louise deMontigny ◽  
George Harper

Challenges to the mid-term timber supply in interior British Columbia resulting from losses to insect outbreaks and wild-fires have prompted interest in silvicultural interventions to hasten growth of regenerating forests, including high-density(overstocked), height-repressed stands of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.). A trialwas established in a dense (4000 to 30 000 trees ha-1) 36-year-old wildfire-origin pine stand in the Cariboo-Chilcotinregion of interior BC to assess the efficacy of thinning, fertilization and a combination of the two treatments for improv-ing tree growth and stand development. Height and diameter of the 36 crop trees in each plot was greater in fertilizedplots then control plots for six years following fertilization, while the height and diameter responses to thinning and thin-ning + fertilization were sustained throughout the 18-year measurement period. Cumulative basal area and volumegrowth of crop trees and all stand trees over the 18-year period was significantly greater in thinned and thinned + fertil-ized treatments than control plots. Projections based on the TASS growth and yield model suggested that total stand vol-umes in thinned plots would surpass that of the control at age 74 and would surpass that of the fertilized treatment at 89years. Unthinned stands (i.e., control and fertilized treatments), did not accumulate significant merchantable volume; inthinned stands (i.e., thinned and thinned + fertilized treatments), the minimum harvest criteria of 80 m3 ha-1 for pine-leading stands in this region was reached at age 102 years. Repeated fertilization would be needed to further hasten standdevelopment. The potential long-term benefits of these silvicultural interventions for timber supply must be weighedagainst treatment costs and risks of mortality related to wildfire, insects and disease. These results highlight the value oflong-term research trials for informing silviculture decisions.


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