scholarly journals Incorporation of Genetic Gain into Growth Projections of Douglas-Fir Using ORGANON and the Forest Vegetation Simulator

2010 ◽  
Vol 25 (2) ◽  
pp. 55-61 ◽  
Author(s):  
Peter J. Gould ◽  
David D. Marshall
Keyword(s):  
Pacific Northwest ◽  
Genetic Gain ◽  
Growth Models ◽  
Regional Growth ◽  
Site Index ◽  
Douglas Fir ◽  
Forest Vegetation ◽  
Planting Density ◽  
Forest Vegetation Simulator ◽  
Stand Management

Abstract Growth models for coast Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) are generally based on measurements of stands that are genetically unimproved (or woods-run); therefore, they cannot be expected to accurately project the development of stands that originate from improved seedlots. In this report, we demonstrate how early expected gain and genetic-gain multipliers can be incorporated into growth projection, and we also summarize projected volume gains and other aspects of stand development under different levels of genetic gain, site productivity, and initial planting density. Representative tree lists that included three levels of productivity (site index = 100, 125, and 150 ft; base = 50 years)and three initial planting densities (302, 435, and 602 trees/ac) were projected from ages 10 to 60 years under three scenarios using two regional growth models (Stand Management Cooperative version of ORGANON and the Pacific Northwest variant of the Forest Vegetation Simulator). The two models projected similar percentage volume gains for improved seedlots. Seedlots with a genetic worth (GW) of 5% for height and diameter growth were projected to have volume gains of 3.3–5.8% over woods-run stands at 40 years and 2.1–3.2% at 60 years. Volume gains were projected to approximately double when GW was increased from 5 to 10%.

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

Evaluating Long-Term Seedling Growth across Densities Using Nelder Plots and the Forest Vegetation Simulator (FVS) in the Black Hills, South Dakota, USA

2021 ◽  
Author(s):  
Wade T Tinkham ◽  
Mike A Battaglia ◽  
Chad M Hoffman
Keyword(s):  
Seedling Growth ◽  
Tree Growth ◽  
Forest Growth ◽  
Forest Vegetation ◽  
Planting Density ◽  
Harvest Scheduling ◽  
Sustainable Harvest ◽  
Forest Vegetation Simulator ◽  
Small Tree ◽  
Fuel Treatment

Abstract Small-tree development affects future stand dynamics and dictates many ecological processes within a site. Accurately representing this critical component of stand development is important for evaluating treatment alternatives from fuel hazard reduction to harvest scheduling. As with all forest growth, competition with other vegetation is known to regulate small-tree growth dynamics. This study uses three Nelder plots with 45 years of ponderosa pine growth to understand competition effects on seedling growth and evaluate the Forest Vegetation Simulator (FVS) Central Rockies (CR) variant’s ability to represent these dynamics. Removal of herbaceous competition before planting increased tree diameters by 50–135% and height by 35–75% across a planting density gradient at age 12. However, by age 45, the effect of herbaceous competition on tree size was no longer evident. Instead, trees at the lowest planting density had diameters 2.5–3 times larger than the most densely grown trees. Forest Vegetation Simulator (FVS) simulations underpredicted diameter at breast height (dbh) by 35–50% and 0–35% for 12 and 45-year-old trees, respectively. There was an underprediction bias of 15–20% for heights at age 12 and overpredictions of 5–10% at age 45. Continuous underprediction of dbh will affect the reliability of modeled fuel treatment longevity and sustainable harvest scheduling. Study Implications: Management and modeling of small-tree growth can affect decision-making for a range of activities, from assessing fuel treatment effectiveness to sustainable harvest scheduling. Effective small-tree density management can increase tree diameters at age 45 by 2.5–3 times the diameter of unthinned sites. FVS-CR underpredicted age 12 heights by 0–45% and age 45 diameters by 0–35% as a function of planting density, suggesting that the model fails to capture the intensity or timing of density-induced competition. These underpredictions will inflate the length of time fuel treatments remain effective and decrease projected sustainable harvest levels supported by responsible management.

Comparison of Douglas-fir site index and height growth curves in the Pacific Northwest

1985 ◽  
Vol 15 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Robert A. Monserud
Keyword(s):  
Pacific Northwest ◽  
Growth Curves ◽  
Site Index ◽  
Height Growth ◽  
Douglas Fir ◽  
Stem Analysis ◽  
The Pacific ◽  
Northern Rockies ◽  
Growth Differences ◽  
Index Curve

Site index and height growth curves produced by the major Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) site index studies in the Pacific Northwest are graphically compared. Results indicate that differences in the height growth pattern of Douglas-fir increase with increasing distance between regions. Height growth differences were extremely small between the northern Rockies and the east side of the Cascades and were rather large between the Rockies and the west side of the Cascades. The relatively small differences between the northern Rockies and the Cascade crest fell between these two extremes. Very small differences were also found between Montana and northern Idaho. A second result of the comparisons is that the type of data and the resulting methodology used to develop the site index curve system are strongly related to the similarity of the resulting curves. Curves derived from felled-tree, stem-analysis studies were quite similar to each other, but differed substantially from curves derived by harmonized guide-curve methods. Furthermore, the guide-curve systems produced curves that were surprisingly similar to each other, even though different varieties of Douglas-fir from different regions were being compared. The magnitude of the differences that could be attributed solely to different methods of site curve construction (stem analysis vs. guide curve) was demonstrated to be quite large by applying both methods to the same data. The often untenable assumptions inherent in guide-curve systems appear to affect the shape of the curves more than real regional height growth differences.

scholarly journals To Thin or Not to Thin: Using the Forest Vegetation Simulator to Evaluate Thinning of Aspen

2003 ◽  
Vol 20 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Daniel W. Gilmore
Keyword(s):  
Site Index ◽  
Forest Vegetation ◽  
Forest Vegetation Simulator ◽  
Precommercial Thinning ◽  
Simulation Tools ◽  
Tree Diameter ◽  
Time Period ◽  
Younger Age ◽  
Volume Production ◽  
A Site

Abstract Thinning experiments are costly to install and take decades of monitoring. Computer simulation tools, however, allow for the creation of “virtual” thinning experiments that forest managers can use as a guide in prescribing thinnings. The Forest Vegetation Simulator (FVS) was used to conduct a “virtual” thinning experiment to a range of residual densities (8, 10, 12, 15, and 20 ft spacings) at a range of thinning ages (5, 10, 25, and 40 yr) over a 50 yr time period. Stand level volume production was not enhanced through precommercial thinning, but average tree diameter was increased. Stand level volume was less after commercial thinnings but total volume production was increased if volumes removed during thinnings were considered. Tree diameter growth was greater when thinnings were performed at a younger age at and at a wider spacing. The greatest total volume production (removed during thinning and standing at age 50) was found to be nearly equal at 8 ft and 10 ft spacing with thinnings occurring at ages 10 or 25 on a site index of 80. North. J. Appl. For. 20(1):14–18.

scholarly journals Projecting Nonnative Douglas Fir Plantations in Southern Europe with the Forest Vegetation Simulator

2017 ◽  
Vol 63 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Cristiano Castaldi ◽  
Giorgio Vacchiano ◽  
Maurizio Marchi ◽  
Piermaria Corona
Keyword(s):  
Douglas Fir ◽  
Forest Vegetation ◽  
Southern Europe ◽  
Forest Vegetation Simulator

Prediction of Douglas-fir fertilizer response using biogeoclimatic properties in the coastal Pacific Northwest

2014 ◽  
Vol 44 (10) ◽  
pp. 1253-1264 ◽  
Author(s):  
K.M. Littke ◽  
R.B. Harrison ◽  
D. Zabowski ◽  
M.A. Ciol ◽  
D.G. Briggs
Keyword(s):  
Pacific Northwest ◽  
Pearson Correlation ◽  
Regression Tree ◽  
Correlation Coefficients ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Annual Increment ◽  
Fertilizer Response ◽  
Boosted Regression Tree

Fertilizer response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) has been related to site and soil properties in the past, but the models have explained only about half of the variation in these investigations. Fertilizer response and percent response after two years were examined, according to mapped and measured biogeoclimatic variables, for 71 Douglas-fir installations in the coastal Pacific Northwest. Paired-tree installations consisted of 12–20 pairs of Douglas-fir trees with one tree fertilized with urea at 224 kg N·ha−1. Pearson correlation coefficients and boosted regression tree (BRT) models were used to determine the best predictor variables and models of Douglas-fir fertilizer response. The BRT models, using the combination of mapped and measured variables, performed the best for predicting fertilizer response. Basal area and volume responses were most related to high forest floor and surface soil carbon to nitrogen ratios. Basal area mean annual increment (MAI) and site index were both negatively correlated with fertilizer response. Also, low basal area MAI was the most important tree measurement for predicting fertilizer response in the BRT models. Installations with many of the predictors from the BRT models (>66% of the model criteria) were found to have a significantly greater fertilizer response than installations with only a few predictors (<33% of the model criteria). These findings support the use of these models for predicting fertilizer response of similar Douglas-fir stands in the coastal Pacific Northwest.

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