Trembling aspen site index in relation to environmental measures of site quality at two spatial scales

2002 ◽  
Vol 32 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Han YH Chen ◽  
Pavel V Krestov ◽  
Karel Klinka
Keyword(s):  
Populus Tremuloides ◽  
Factor Model ◽  
Spatial Scales ◽  
Site Index ◽  
Site Quality ◽  
Slope Aspect ◽  
Moisture Regime ◽  
Trembling Aspen ◽  
Geographic Scale ◽  
Environmental Measures

To evaluate the variation in trembling aspen (Populus tremuloides Michx.) productivity at a large geographic scale, we examined the relationships between site index and environmental factors from 142 even-aged, fully stocked stands located on a variety of sites across interior British Columbia. Site index was derived from stem analysis and the environmental measures included climate surrogates (latitude, longitude, and elevation), biogeoclimatic zone, slope– aspect, actual soil moisture regime (SMR), and soil nutrient regime (SNR). The spatial gradients (latitude, longitude, and elevation), slope–aspect, SMR, and SNR affected aspen site index, but their relationships greatly varied with biogeoclimatic zone. At the provincial scale, these relationships were weaker than on the zonal scale. Among the models developed for predicting aspen site index, we recommend the zone-specific all-factor model for application, which explained 82% of the variation of site index and provided unbiased and precise predictions.

Building a dynamic growth model for trembling aspen in western Canada without age data

2013 ◽  
Vol 43 (3) ◽  
pp. 256-265 ◽  
Author(s):  
Oscar García
Keyword(s):  
Populus Tremuloides ◽  
Site Occupancy ◽  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Site Quality ◽  
Diameter Distribution ◽  
Stand Age ◽  
Parameter Estimates ◽  
Trembling Aspen

A biologically inspired whole-stand growth and yield model was developed for even-aged thinned or unthinned stands dominated by trembling aspen (Populus tremuloides Michx.). The estimation used permanent sample plot data from British Columbia, Alberta, Saskatchewan, and Manitoba, supplemented by published site index and young stand information. An ingrowth imputation procedure was devised to facilitate the use of plot measurements where small trees are not measured. Two published site index models were closely approximated by a simple age-base invariant equation. Good parameter estimates for mortality and basal area growth were obtained without using age observations, which were unreliable or missing. Four differential equations describe the dynamics of top height, trees per hectare, basal area, and a site occupancy factor. Current values of these variables are used to estimate total and merchantable volumes up to any diameter limit and diameter distribution parameters. When an independent source of site quality estimates is available, the final model does not require stand age knowledge for making growth and yield predictions.

scholarly journals Soil-Site Relations for Trembling Aspen in Northwest Ontario

1998 ◽  
Vol 15 (3) ◽  
pp. 146-153 ◽  
Author(s):  
Willard H. Carmean ◽  
Janjun Li
Keyword(s):  
Clay Content ◽  
Site Index ◽  
Growth And Yield ◽  
Site Quality ◽  
Trembling Aspen ◽  
Stem Analysis ◽  
Drainage Class ◽  
Soil Site ◽  
Northwest Ontario ◽  
Aspen Forest

Abstract Past harvesting in Northwest Ontario has produced increased regeneration and increased forest areas supporting trembling aspen stands, resulting in greatly increased utilization of aspen. Thus there is a critical need to accurately estimate site quality and growth and yield for trembling aspen and for identifying productive sites where more intensive aspen forest management can be practiced. Soil-site relations were studied using 95 plots located in mature, fully stocked, evenaged, undisturbed trembling aspen stands. On each plot site index (SIBH50) estimation was based on stem analysis of three to five dominant and codominant trees. Each plot also had soil profile descriptions and soil analyses for four major soil horizons (A, B, BC, C). Plots were located on morainal soils, glaciofluvial soils, and lacustrine soils. Multiple regression analyses showed: (a) for morainal soils site index was correlated (adj R² = 0.63) to depth to a root restricting layer, silt plus clay content of the A horizon, and coarse fragment content of the C horizon; (b) for glaciofluvial soils site index was correlated (adj R² = 0.64) to depth to a root restricting layer and to drainage class: and (c) for lacustrine soils site index was correlated (adj R² = 0.65) to depth to mottles and to clay content of the C horizon. Results are applicable only to medium and good sites where mature, fully stocked, merchantable trembling aspen stands commonly occur. North. J. Appl. For. 15(3):146-153.

Tree-ring evidence extends the historic northern range limit of severe defoliation by insects in the aspen stands of western Quebec, Canada

2008 ◽  
Vol 38 (9) ◽  
pp. 2535-2544 ◽  
Author(s):  
Jian-Guo Huang ◽  
Jacques Tardif ◽  
Bernhard Denneler ◽  
Yves Bergeron ◽  
Frank Berninger
Keyword(s):  
Tree Ring ◽  
Populus Tremuloides ◽  
Host Species ◽  
Spatial Scales ◽  
Regional Scale ◽  
Trembling Aspen ◽  
Range Limit ◽  
Insect Outbreaks ◽  
Northern Latitudes ◽  
Northern Range Limit

A dendrochronological reconstruction of insect outbreaks was conducted along a latitudinal gradient from 46°N to 54°N in the boreal forest of western Quebec, Canada. Tree-ring chronologies of the host species, trembling aspen ( Populus tremuloides Michx.), were constructed to identify periods of severe defoliation and comparisons were made with tree-ring chronologies of nonhost species. In addition, the frequency of white and narrow rings was used to further confirm the occurrence of insect outbreaks at these latitudes. Some major outbreaks occurred in relatively close synchrony at the regional scale, but the initiation year, intensity, and extent of the outbreaks varied spatially. For example, the 1950s outbreaks were observed from 1951 to 1952 at 46°N, from 1953 to 1954 at 47°N, and from 1954 to 1956 at 48°N. Other major outbreaks like the 1964 and 1980 outbreaks were fairly well synchronized at northern latitudes. The observed outbreaks in trembling aspen stands at 54°N also provided clear evidence that severe insect defoliation occurs much further north than the currently reported range limit, that is, between 49°N and 51°N, of the most important trembling aspen defoliator, the forest tent caterpillar ( Malacosoma disstria Hubner). Our study demonstrated that careful identification of white rings in host species can provide valid information allowing the expansion of the forestry insect inventory database both at temporal and spatial scales.

Genotypic variation and recovery of Populus tremuloides from biomass removal and compaction in northern Wisconsin, USA

2005 ◽  
Vol 35 (1) ◽  
pp. 221-228 ◽  
Author(s):  
J G Bockheim ◽  
H Park ◽  
J Gallagher
Keyword(s):  
Populus Tremuloides ◽  
Forest Floor ◽  
Genotypic Variation ◽  
Basal Area ◽  
Site Index ◽  
Height Growth ◽  
Site Quality ◽  
Long Term Effects ◽  
Biomass Removal

This study was initiated in 1990 to determine the effects of simulated logging practices on long-term productivity of trembling aspen (Populus tremuloides Michx.). Treatments included three levels of biomass removal (entire aboveground woody biomass, control; control + coarse woody detritus, LS; and LS + forest floor, FF) and two levels of compaction (light compaction on winter skid roads, TRA; heavy simulated compaction with FF, COM). The study was conducted on a Typic Haplorthod and a Haplic Glossudalf of medium site quality (site index50 years = 21 and 23 m, respectively) on the Brule State Forest. Twelve years after treatment, the following results were noted: (1) there were no significant differences in aspen height growth among treatments at either site except for lower stocking, height, diameter, and basal area on heavily compacted plots (COM, forest floor removed before compaction) at the clay site; (2) there was considerable genotypic variation in aspen height growth; and (3) recovery of physical properties, as reflected by bulk density, occurred within 12 years of treatment but was not manifested by improved aspen growth. These results suggest that concern over long-term effects of intensified biomass removal and soil compaction should be matched by a concern over protection of the aspen gene pool in the upper Great Lakes region.

Climate sensitivity of trembling aspen radial growth along a productivity gradient in northeastern British Columbia, Canada

2008 ◽  
Vol 38 (5) ◽  
pp. 1211-1222 ◽  
Author(s):  
Giovanni Leonelli ◽  
Bernhard Denneler ◽  
Yves Bergeron
Keyword(s):  
British Columbia ◽  
Populus Tremuloides ◽  
Radial Growth ◽  
Site Index ◽  
Future Climate Change ◽  
Trembling Aspen ◽  
Tree Ring Chronology ◽  
Index Model ◽  
Productivity Gradient ◽  
Site Index Model

Growth–climate relationships were analyzed for 15 stands of trembling aspen ( Populus tremuloides Michx.) along a productivity gradient in northeastern British Columbia. Productivity was evaluated with a site index model whose values varied between 6.65 and 26.93 m height at age 50 years. To assess the role of climate on radial growth, we built a tree-ring chronology for each site and then performed a dendroclimatic analysis by means of bootstrapped correlation functions using monthly and annual climatic variables. We found that trembling aspen sensitivity to climate varied across stands with different productivities in the study area. At the more productive sites, trees were more sensitive to climate, and ring widths were positively correlated, particularly with summer month precipitation prior to the year of growth. The different responses to climate along the productivity gradient are likely related to the differences in substrate properties; substrates at the more productive sites are richer in nutrients and have a better water holding capacity than those of the less productive sites. Our study suggests that the effects of future climate change on tree growth may not only increase towards the limit of a species distribution, but also towards richer and wetter stands.

Structure and dynamics of trembling aspen – white spruce mixed stands near Fort Nelson, B.C.

2004 ◽  
Vol 34 (2) ◽  
pp. 384-395 ◽  
Author(s):  
Richard Kabzems ◽  
Oscar García
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Stand Structure ◽  
White Spruce ◽  
Structure Type ◽  
Growth Patterns ◽  
Site Quality ◽  
Diameter Growth ◽  
Trembling Aspen ◽  
Mixed Stands

The trembling aspen (Populus tremuloides Michx.) – white spruce (Picea glauca (Moench) Voss) mixed woods near Fort Nelson are distinguished by the large size of individual trees, longevity, and the low occurrence of internal decay in trembling aspen. The development of these forest ecosystems has had limited documentation and may be significantly different than those described in other portions of the boreal forest. At five study stands, stem analysis techniques were used to examine the patterns of height and radial growth over time according to species and structure type. There were two patterns of species establishment that were consistent with the stand structure. In codominant stands, recruitment periods for trembling aspen and white spruce overlapped. The stratified stands were consistently associated with a 29- to 58-year lag in white spruce recruitment. Spruce that were codominant with aspen at the time of sampling had sustained periods of rapid height and diameter growth. White spruce that were later to establish on site had slower rates of height and diameter growth. White spruce ages indicated that a dominant recruitment episode was more common than continuous recruitment. Height and diameter growth of trembling aspen were similar in both stand types. The differences in trembling aspen growth patterns between stands were due to site quality. The white spruce in codominant stands did not appear to go through a period of suppression and then release associated with stand-level trembling aspen mortality, as commonly described for other boreal mixedwoods. The vigor and longevity of trembling aspen in Fort Nelson appear to prolong the period of trembling aspen domination of mixed stands well beyond the time periods observed in other boreal ecosystems.

scholarly journals Ethylene enhances root water transport and aquaporin expression in trembling aspen (Populus tremuloides) exposed to root hypoxia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiangfeng Tan ◽  
Mengmeng Liu ◽  
Ning Du ◽  
Janusz J. Zwiazek
Keyword(s):  
Gas Exchange ◽  
Water Transport ◽  
Populus Tremuloides ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Trembling Aspen ◽  
Expression Levels ◽  
Root Hypoxia ◽  
Exogenous Ethylene

Abstract Background Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. Results In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. Conclusions Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.

The bacteria in sapwood, wetwood, and heartwood of trembling aspen (Populus tremuloides)

1973 ◽  
Vol 51 (2) ◽  
pp. 498-500 ◽  
Author(s):  
Donald M. Knutson
Keyword(s):  
Populus Tremuloides ◽  
Trembling Aspen ◽  
Indigenous Bacteria ◽  
Large Populations ◽  
Xylem Tissue

Bacteria (Erwinia, Bacillus) were consistently isolated from all samples of aspen sapwood and heartwood. In wetwood zones (water-soaked xylem tissue) or discolored heartwood, large populations often occur. No organisms unique to wetwood were isolated. Wetwood probably is formed by nonmicrobial means and, once formed, merely supports large populations of indigenous bacteria.

Linking climate, gross primary productivity, and site index across forests of the western United States

2011 ◽  
Vol 41 (8) ◽  
pp. 1710-1721 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Nicholas L. Crookston ◽  
Philip J. Radtke
Keyword(s):  
Climate Change ◽  
Growth Models ◽  
Gross Primary Production ◽  
Site Index ◽  
Nonparametric Model ◽  
Climate Change Scenarios ◽  
Geographic Scale ◽  
Potential Productivity ◽  
The One ◽  
The Relationship

Assessing forest productivity is important for developing effective management regimes and predicting future growth. Despite some important limitations, the most common means for quantifying forest stand-level potential productivity is site index (SI). Another measure of productivity is gross primary production (GPP). In this paper, SI is compared with GPP estimates obtained from 3-PG and NASA’s MODIS satellite. Models were constructed that predict SI and both measures of GPP from climate variables. Results indicated that a nonparametric model with two climate-related predictor variables explained over 68% and 76% of the variation in SI and GPP, respectively. The relationship between GPP and SI was limited (R2 of 36%–56%), while the relationship between GPP and climate (R2 of 76%–91%) was stronger than the one between SI and climate (R2 of 68%–78%). The developed SI model was used to predict SI under varying expected climate change scenarios. The predominant trend was an increase of 0–5 m in SI, with some sites experiencing reductions of up to 10 m. The developed model can predict SI across a broad geographic scale and into the future, which statistical growth models can use to represent the expected effects of climate change more effectively.

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