Testing the Lake States variant of FVS (Forest Vegetation Simulator) for the main forest types of northern Ontario

2004 ◽  
Vol 80 (4) ◽  
pp. 495-506 ◽  
Author(s):  
V. Lacerte ◽  
G R Larocque ◽  
M. Woods ◽  
W J Parton ◽  
M. Penner
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Stand Density ◽  
Site Index ◽  
Forest Vegetation ◽  
Forest Vegetation Simulator ◽  
Consistency Analysis ◽  
Northern Ontario ◽  
Individual Tree ◽  
Stand Basal Area

The Lake States variant of the FVS (Forest Vegetation Simulator) model (LS-FVS), also known as the LS-TWIGS variant of FVS, was validated for black spruce (Picea mariana (Mill.) BSP), white spruce (Picea glauca (Moench) Voss), jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) forests in northern Ontario. Individual-tree data from 537 remeasured sample plots were used. This dataset included different combinations of site index, stand density and age. It was possible to compare observations and predictions for different projection length periods. The validation exercise included a biological consistency analysis, the computation of mean percent difference (MPD) for stand density, stand basal area, top height and quadratic mean diameter (QMD) and the comparison of observed and predicted individual-tree dbh. The biological consistency analysis indicated that LS-FVS logically predicted the effect of site index on top height, stand basal area and QMD for black spruce and jack pine. However, the decrease in stand basal area at young ages was inconsistent with the normal development pattern of the forest stands under study and was attributed to deficiencies in the prediction of mortality. LS-FVS was found to underpredict stand density, stand basal area and top height and to over-predict QMD. Even though there were large errors in the prediction of change in stand density, LS-FVS was nevertheless consistent in the prediction of the shape of the dbh size distribution. Key words: FVS, Forest Vegetation Simulator, validation, biological consistency analysis

Individual-tree basal area growth models for jack pine and black spruce in northern Ontario

2004 ◽  
Vol 80 (3) ◽  
pp. 366-374 ◽  
Author(s):  
Lianjun Zhang ◽  
Changhui Peng ◽  
Qinglai Dang
Keyword(s):  
Tree Growth ◽  
Black Spruce ◽  
Basal Area ◽  
Jack Pine ◽  
Mixed Stands ◽  
Northern Ontario ◽  
Individual Tree ◽  
Basal Area Growth ◽  
Wide Range ◽  
Area Growth

Individual-tree models of five-year basal area growth were developed for jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP) in northern Ontario. Tree growth data were collected from long-term permanent plots of pure and mixed stands of the two species. The models were fitted using mixed model methods due to correlated remeasurements of tree growth over time. Since the data covered a wide range of stand ages, stand conditions and tree sizes, serious heterogeneous variances existed in the data. Therefore, the coefficients of the final models were obtained using weighted regression techniques. The models for the two species were evaluated across 4-cm diameter classes using independent data. The results indicated (1) the models of jack pine and black spruce produced similar prediction errors and biases for intermediate-sized trees (12–28 cm in tree diameter), (2) both models yielded relatively large errors and biases for larger trees (> 28 cm) than those for smaller trees, and (3) the jack pine model produced much larger errors and biases for small-sized trees (< 12 cm) than did the black spruce model. Key words: mixed models, repeated measures, model validation

scholarly journals Practical Extension of a Lake States Tree Height Model

2008 ◽  
Vol 25 (4) ◽  
pp. 186-194 ◽  
Author(s):  
Don C. Bragg
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Site Index ◽  
Individual Response ◽  
White Pine ◽  
Eastern White Pine ◽  
Tree Model ◽  
Individual Tree ◽  
Height Model

Abstract By adapting data from national and state champion lists and the predictions of an existing height model, an exponential function was developed to improve tree height estimation. As a case study, comparisons between the original and redesigned model were made with eastern white pine (Pinus strobus L.). For example, the heights predicted by the new design varied by centimeters from the original until the pines were more than 25 cm dbh, after which the differences increased notably. On a very good site (50-year base age site index [SI50] = 27.4 m) at the upper end of the range of basal area (BA; 68.9 m2/ha) for the region, the redesigned model predicted a champion-sized eastern white pine (actual measurements: 97.0 cm dbh, 50.9 m tall) to be 51.3 m tall, compared with 38.8 m using the original formulation under the same conditions. The NORTHWDS Individual Response Model (NIRM) individual tree model further highlighted the influence of these differences with long-term simulations of eastern white pine height. On a moderate site (SI50 = 18.7 m) with intermediate (BA = 15 m2/ha) stand density, NIRM results show that the original model consistently predicts heights to be 20–30% lower for mature white pine.

scholarly journals Aspects of ecological development in managed stands of jack pine and black spruce in northern Ontario: Understory vegetation and nutrient relations

2005 ◽  
Vol 81 (1) ◽  
pp. 61-72 ◽  
Author(s):  
S L Hunt ◽  
A M Gordon ◽  
D M Morris
Keyword(s):  
Species Composition ◽  
Forest Floor ◽  
Black Spruce ◽  
Basal Area ◽  
Jack Pine ◽  
Understory Vegetation ◽  
Northern Ontario ◽  
Nutrient Pools ◽  
Site Type ◽  
Stand Basal Area

This study investigated relationships between understory vegetation and nutrient pools in managed stands of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] BSP) in the Lake Nipigon region of northern Ontario. The species composition, biomass, and nutrient pool sizes in the understory vegetation, as well as biomass and nutrient pools in trees and soils, were determined in 16 managed stands ranging in age from 10 to 53 years since establishment and one mature, natural stand. Patterns of above-ground biomass accumulation in understory vegetation varied with overstory tree species and general site type (dry, sandy soils, or mesic, finer-textured soils). Understory vegetation contributed little (0.3 to 2.6%) to total above-ground organic matter (live biomass plus forest floor) but accounted for higher proportions of total above-ground nutrient pools (e.g., 0.7 to 3.4% of N; 3.2 to 11.7% of K) and net primary productivity (1.2 to 21.2%). The species composition of the understory vegetation was strongly related to stand basal area as well as to concentrations of nutrients (N, P, K, Ca, Mg) in the forest floor and mineral soil. The greatest amount of change in vegetation community composition occurred from the pre-to post-canopy closure stages of stand development; fewer differences were observed among stands of a given species and site type 35 to 50 years after establishment. The effects of silvicultural practices were detected in certain stands 35 years after establishment; for example the most severely treated (bladed and thinned) jack pine stand differed from other stands of similar age and soils with its Cladina/Vaccinium-dominated understory, and large amounts of biomass in the moss/lichen stratum. The understory vegetation communities in other managed jack pine stands, by 35 to 50 years, were similar to that of the mature, natural stand, indicating resilience to silvicultural disturbances. Silviculture may have lasting effects on understory vegetation biomass and species composition through its effects on stand basal area, overstory species, and soil nutrients. This research serves as baseline information for further studies into the ecology of managed stands in northern Ontario. Key words: understory, nutrients, managed forests, jack pine, black spruce, canonical correspondence analysis

scholarly journals Accuracy and Precision of 10 Year Predictions for Forest Vegetation Simulator—Lake States

2000 ◽  
Vol 17 (2) ◽  
pp. 62-70 ◽  
Author(s):  
Seal J. Canavan ◽  
Carl W. Ramm
Keyword(s):  
Basal Area ◽  
Forest Vegetation ◽  
Individual Species ◽  
Diameter Growth ◽  
Forest Vegetation Simulator ◽  
White Oak ◽  
Individual Tree ◽  
Projection System ◽  
Accuracy And Precision ◽  
Lake States

Abstract This study is a followup to the 5 yr validation of the Lake States TWIGS (The Woodsman's Ideal Growth Projection System) projection system by Guertin and Ramm (1996). Accuracy and precision of 10 yr diameter growth, basal area growth and mortality predicted by the Lake States variant of the Forest Vegetation Simulator (FVS) were evaluated for seven upland hardwood species in Michigan's northern Lower Peninsula. The robustness of FVS predictions was examined by varying projection cycle length and the level of detail of stand and tree-information included in growth projections.The data used in the analysis consisted of individual tree measurements from 44 stands across 10 ecological land type phases in the Manistee National Forest. FVS-Lake States was found to consistently overpredict 10 yr diameter growth across all seven species. Ten year diameter growth was predicted within ±0.5 in. across all projections for nearly all species and size-class combinations for the seven species examined. Basal area and mortality errors were less consistent. Mean errors for trees per acre ranged from -24 for red maple to +14 for white oak. These errors led to a consistent overprediction of basal area per acre for all species combined, while prediction errors for individual species were less than ±8 ft²/ac. Precision was variable, especially for mortality predictions. The most accurate predictions were obtained with longer cycle lengths and with projections using tree diameter, tree height, and crown ratio along with site index and individual tree past diameter growth. North. J. Appl. For. 17(2):62-70.

Stand growth responses after fertilization for thinned lodgepole pine, Douglas-fir, and spruce in forests of interior British Columbia, Canada

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 ◽  
...  
Keyword(s):  
British Columbia ◽  
Picea Glauca ◽  
Lodgepole Pine ◽  
Basal Area ◽  
Stand Density ◽  
Site Index ◽  
Douglas Fir ◽  
Picea Sitchensis ◽  
Growth And Yield ◽  
Growth Responses

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.

scholarly journals Regional Height–Diameter Equations for Major Tree Species of Southwest Oregon

2007 ◽  
Vol 22 (3) ◽  
pp. 213-219 ◽  
Author(s):  
Hailemariam Temesgen ◽  
David W. Hann ◽  
Vincente J. Monleon
Keyword(s):  
Relative Position ◽  
Tree Species ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Individual Tree ◽  
Fit Statistics ◽  
Alternative Measures ◽  
Southwest Oregon ◽  
Accuracy Of Prediction

Abstract Selected tree height and diameter functions were evaluated for their predictive abilities for major tree species of southwest Oregon. Two sets of equations were evaluated. The first set included four base equations for estimating height as a function of individual tree diameter, and the remaining 16 equations enhanced the four base equations with alternative measures of stand density and relative position. The inclusion of the crown competition factor in larger trees (CCFL) and basal area (BA), which simultaneously indicates the relative position of a tree and stand density, into the base height–diameter equations increased the accuracy of prediction for all species. On the average, root mean square error values were reduced by 45 cm (15% improvement). On the basis of the residual plots and fit statistics, two equations are recommended for estimating tree heights for major tree species in southwest Oregon. The equation coefficients are documented for future use.

Preliminary Site Index Equations for Three Planted Species in Northern Ontario

1995 ◽  
Vol 12 (2) ◽  
pp. 57-63 ◽  
Author(s):  
Bijan Payandeh ◽  
Yonghe Wang
Keyword(s):  
Nonlinear Analysis ◽  
Black Spruce ◽  
Analysis Data ◽  
Site Index ◽  
Analysis Of Covariance ◽  
Stem Analysis ◽  
Northern Ontario ◽  
Natural Stand ◽  
Graphical Comparison ◽  
Similarities And Differences

Abstract Stem analysis data from plantations of black spruce, white spruce, and jack pine from northern Ontario were fitted to base-age specific and base-age invariant site index models. The resulting equations and their respective parameters were compared via nonlinear analysis of covariance. The base-age specific models produced a somewhat better fit to the data than their base-age invariant counterparts, although the latter are considered theoretically more elegant. Graphical comparison of plantation and natural stand site index curves for the three species showed both similarities and differences. North. J. Appl. For. 12(2):57-63.

Stand density management diagram for managed black spruce stands

1994 ◽  
Vol 70 (1) ◽  
pp. 65-74 ◽  
Author(s):  
P. F. Newton ◽  
G. F. Weetman
Keyword(s):  
Black Spruce ◽  
Stand Density ◽  
Northern Ontario ◽  
Site Class ◽  
Permanent Sample Plots ◽  
Kalmia Angustifolia ◽  
Initial Spacing ◽  
Stand Density Management ◽  
Crown Closure ◽  
Stand Density Management Diagram

A stand density management diagram for managed black spruce (Picea mariana (Mill.) B.S.P.) stands was developed using data derived from 37 variable-size temporary and permanent sample plots, and 257 open-grown sample trees. The plots were situated within 15 plantations and 4 precommercially thinned stands located throughout central and western Newfoundland, north-western New Brunswick and northern Ontario. The basic components of the diagram included: (1) an approximate crown closure line (2) the self-thinning rule (3) expected size-density trajectories and (4) isolines for dominant height, relative density index, quadratic mean diameter and merchantability ratio. The utility of the diagram was demonstrated by deriving yields for various initial spacings by site class and subsequently evaluating various outcomes in terms of operability criteria. In addition, the potential of estimating the time of crown closure by initial spacing and site class is discussed in relation to minimizing the adverse effects of Kalmia angustifolia (L.) on black spruce growth and development. Key words: stand density management diagram, initial spacing, black spruce, operability, Kalmia angustifolia (L.)

Subalpine forest damage from a severe windstorm in northern Colorado

2001 ◽  
Vol 31 (12) ◽  
pp. 2089-2097 ◽  
Author(s):  
Thomas T Veblen ◽  
Dominik Kulakowski ◽  
Karen S Eisenhart ◽  
William L Baker
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Stand Density ◽  
Wind Damage ◽  
Forest Damage ◽  
Forest Composition ◽  
Subalpine Forest ◽  
Individual Tree ◽  
Northern Colorado ◽  
Standing Dead

As windstorm intensity increases above some threshold, disturbance spread and damage patterns are expected to be less strongly shaped by preblowdown forest composition and structure than by the pattern of the storm itself. We examined this generalization by analyzing differences in wind damage among tree species and stands following a severe blowdown in 1997 affecting over 10 000 ha of subalpine forest in the Routt Divide area of northern Colorado, U.S.A. Individual tree traits such as species, height, and status as standing dead or alive strongly influenced the amount and type (uprooting vs. snapping) of wind damage. Populus tremuloides Michx. exhibited much less uprooting and overall damage than the conifers. Among the canopy trees of the conifer species, Pinus contorta Dougl. ex. Loud and Abies lasiocarpa (Hook.) Nutt. sustained the lowest and highest rates of snapping, respectively. Standing dead conifers were more likely to be snapped than uprooted, and taller trees were more likely to be damaged than shorter trees. Stand-level characteristics such as stand density, amount of dead basal area, and species composition were predictive of the amount of wind damage for areas of moderate- but not high-severity blowdown. Even in such an extreme windstorm as the Routt blowdown, which had estimated wind speeds of 200–250 km/h, individual tree attributes and stand-level characteristics significantly influenced the severity and type of wind damage.

Predicting basal area increment in a spatially explicit, individual tree model: a test of competition measures with black spruce

2003 ◽  
Vol 33 (3) ◽  
pp. 435-443 ◽  
Author(s):  
Daniel Mailly ◽  
Sylvain Turbis ◽  
David Pothier
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Basal Area Increment ◽  
Spatially Explicit ◽  
Competition Index ◽  
Individual Tree ◽  
Spatial Indices ◽  
Crown Shape ◽  
Spruce Stands ◽  
Competition Indices

A current trend in the development of forest stand models is to use spatially explicit, individual-tree information to simulate forest dynamics with increased accuracy. By adding spatial information, such as tree coordinates, crown shape, and size, it is hypothesized that the computation of the model's driving function is improved over traditional competition indices, especially when simulating multistoried stands. In this paper, we want to test whether computationally demanding competition indices outperform traditional indices in predicting mean basal area increment. The study was undertaken in old, uneven-aged black spruce (Picea mariana (Mill.) BSP) stands in northeastern Quebec, Canada. The predictability of individual tree growth rates was related to crown dimensions and other stand and tree variables measured in the field. Data were collected from 90 trees coming from stands of varying site quality (range 9.6–16.5 m height at 50 years, age taken at 1 m) and age (range 66–257 years). Hegyis's distance-dependent competition index was found to be the most strongly correlated competition measure (r = 0.57) with mean basal area growth of the last 20 years. This value, 12% higher than the value obtained from the best distance-independent competition index (r = 0.45), clearly shows that precision gains can be achieved when estimating basal area increment with spatial indices in black spruce stands. Using indices computed from virtual hemispherical images did not prove superior to simpler distance-dependent indices based on their individual correlations with basal area increment. When included in a basal area increment model for the last 20 years of growth, however, the gains in precision were comparable to Hegyi's competition index. This indicates that indices derived from a hemispherical approach have some value in spatially explicit forest simulations models but that further tests using younger stands are needed to confirm this result in black spruce stands.

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