scholarly journals Stand-level mortality models for Nordic boreal forests

Silva Fennica ◽  
2020 ◽  
Vol 54 (5) ◽  
Author(s):  
Jouni Siipilehto ◽  
Micky Allen ◽  
Urban Nilsson ◽  
Andreas Brunner ◽  
Saija Huuskonen ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Basal Area ◽  
Stand Density ◽  
Logistic Function ◽  
National Forest Inventory ◽  
Growth And Yield ◽  
Stand Age ◽  
Probability Of Survival ◽  
Mortality Models

New mortality models were developed for the purpose of improving long-term growth and yield simulations in Finland, Norway, and Sweden and were based on permanent national forest inventory plots from Sweden and Norway. Mortality was modelled in two steps. The first model predicts the probability of survival, while the second model predicts the proportion of basal area in surviving trees for plots where mortality has occurred. In both models, the logistic function was used. The models incorporate the variation in prediction period length and in plot size. Validation of both models indicated unbiased mortality rates with respect to various stand characteristics such as stand density, average tree diameter, stand age, and the proportion of different tree species, Scots pine ( L.), Norway spruce ( (L.) Karst.), and broadleaves. When testing against an independent dataset of unmanaged spruce-dominated stands in Finland, the models provided unbiased prediction with respect to stand age.Pinus sylvestrisPicea abies

scholarly journals Long-term influence of stand thinning and repeated fertilization on forage production in young lodgepole pine forests

2017 ◽  
Vol 47 (8) ◽  
pp. 1123-1130 ◽  
Author(s):  
Pontus M.F. Lindgren ◽  
Thomas P. Sullivan ◽  
Douglas B. Ransome ◽  
Druscilla S. Sullivan ◽  
Lisa Zabek
Keyword(s):  
Pinus Contorta ◽  
Large Scale ◽  
Bos Taurus ◽  
Lodgepole Pine ◽  
Stand Density ◽  
Stand Age ◽  
Forage Production ◽  
South Central ◽  
Stand Thinning

Integration of trees with forage and livestock production as silvopastoralism is another potential component of intensive forest management. Stand thinning and fertilization may enhance growth of crop trees and understory forage for livestock. We tested the hypothesis that large-scale precommercial thinning (PCT) (particularly heavy thinning to ≤1000 stems·ha−1) and repeated fertilization, up to 20 years after the onset of treatments, would enhance production of graminoids, forbs, and shrubs as cattle (Bos taurus L.) forage. Results are from two long-term studies: (1) PCT (1988–2013) and (2) PCT with fertilization (PCT–FERT) (1993–2013) of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands in south-central British Columbia, Canada. Mean biomass estimates of graminoids, forbs, total herbs, and shrubs were not affected by stand density. However, fertilization enhanced mean biomass estimates of graminoids, forbs, and total herbs, but not shrubs. Thus, the density part of our hypothesis was not supported, but the nutrient addition part was supported at least for the herbaceous components. Biomass of the herbaceous understory was maintained as a silvopasture component for up to 20 years (stand age 13 to 33 years) in fertilized heavily thinned stands prior to canopy closure.

scholarly journals Stand-Level Components of a Growth and Yield Model for Nothofagus Mixed Forests from Southern Chile

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 810
Author(s):  
Sebastian Palmas ◽  
Paulo C. Moreno ◽  
Wendel P. Cropper ◽  
Alicia Ortega ◽  
Salvador A. Gezan
Keyword(s):  
Forest Type ◽  
Geographical Area ◽  
Basal Area ◽  
Forest Growth ◽  
Model Systems ◽  
Growth And Yield ◽  
Permanent Plots ◽  
Stand Age ◽  
Yield Model ◽  
Mixed Forests

Reliable information on stand dynamics and development is needed to improve management decisions on mixed forests, and essential tools for this purpose are forest growth and yield (G&Y) models. In this study, stand-level G&Y models were built for cohorts within the natural mixed second-growth Nothofagus-dominated forests in Chile. All currently available (but limited) data, consisting of a series of stratified temporary and permanent plots established in the complete range of this forest type, were used to fit and validate these models. Linear and nonlinear models were considered, where dominant stand age, number of trees, and the proportion of basal area of Nothofagus species resulted in significant predictors to project future values of stand basal area for the different cohorts (with R2 > 0.51 for the validation datasets). Mortality was successfully modeled (R2 = 0.79), based on a small set of permanent plots, using the concept of self-thinning with a proposed model defined by the idea that, as stands get closer to a maximum density, they experience higher levels of mortality. The evaluation of these models indicated that they adequately represent the current understanding of dynamics of basal area and mortality of Nothofagus and companion species in these forests. These are the first models fitted over a large geographical area that consider the dynamics of these mixed forests. It is suggested that the proposed models should constitute the main components of future implementations of G&Y model systems.

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.

Long-Term Development of Regeneration Under Longleaf Pine Seedtree and Shelterwood Stands

1993 ◽  
Vol 17 (1) ◽  
pp. 10-15 ◽  
Author(s):  
William D. Boyer
Keyword(s):  
Seed Production ◽  
Seedling Establishment ◽  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Stand Density ◽  
Distribution Characteristic ◽  
Volume Increment ◽  
Potential Impact

Abstract Well-stocked mature longleaf pine (Pinus palustris Mill.) stands were cut to five residual basal areas in 1957, namely 9, 18, 27, 36, and 45 ft² per ac, to observe the effect of stand density on seed production and seedling establishment. Seedlings, mainly from the 1955 or 1961seed crops, were established in treated stands. All pines on net 0.9 ac plots were remeasured in 1991 to determine the effect of residual pine density on development of the regeneration. Even the lightest residual overstory converted the structure of 29- to 35- yr-old ingrowth into the reverse-Jdiameter class distribution characteristic of uneven-aged stands. Four or six residual trees, now comprising 7 to 10 ft² basal area (ba)/ac, reduced ingrowth basal area to about half that of same-aged stands released from overstory competition. Merchantable volume of ingrowth under theselow residual densities averaged 40% of that in released stands. Mean annual per ac volume increment of ingrowth averaged 21 to 22 ft³ under the 9 ft² density but did not exceed 7 ft³ under any residual density above this. The potential impact of significant growth reductionsshould be taken into account when considering uneven-aged management methods for longleaf pine. South. J. Appl. For. 17(1):10-15.

scholarly journals Species Mixing Regulation with Respect to Forest Ecosystem Service Provision

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 632 ◽  
Author(s):  
Fabian Schwaiger ◽  
Werner Poschenrieder ◽  
Peter Biber ◽  
Hans Pretzsch
Keyword(s):  
Forest Management ◽  
Groundwater Recharge ◽  
Ecosystem Service ◽  
Service Provision ◽  
Quantitative Methods ◽  
Basal Area ◽  
Stand Density ◽  
European Beech ◽  
Stand Age ◽  
Mixed Stands

The control and maintenance of species composition of mixed stands is a highly relevant objective of forest management in order to provide multifunctionality and climatic resilience. In contrast to this requirement there is, however, an evident lack of quantitative methods for mixture regulation. In this context, we propose an approach for the regulation of mixture proportions that has been implemented in a forest management model. The approach considers species-specific growth characteristics and takes into account the mixing effect on stand density. We present five exemplary simulations that apply the regulation. Each simulation maintains one of five desired species compositions. In these simulations, we consider the species European beech and Norway spruce under good site conditions, thus representing the most prominent mixed stands in Central Europe. Based on this model experiment, we analyze the potential benefit of controlled mixing regulation for achieving desired levels and combinations of ecosystem service provision, in particular productivity, diversity, and groundwater recharge. We found that a constant 50% basal area share of beech (equivalent growing space share of 80% to 70% depending on stand age) provided the most balanced supply of ecosystem services. Prominently, groundwater recharge considerably decreased when beech basal area shares were held below 50%. We discuss the ecological and practical implications of the regulation approach and different mixing shares.

scholarly journals Dynamik dichter, gleichförmiger Gebirgsfichtenwälder

2013 ◽  
Vol 164 (2) ◽  
pp. 37-46 ◽  
Author(s):  
Peter Bebi ◽  
Frank Krumm ◽  
Urs-Beat Brändli ◽  
Andreas Zingg
Keyword(s):  
Basal Area ◽  
Field Studies ◽  
National Forest Inventory ◽  
Active Management ◽  
Small Scale ◽  
Mountain Forests ◽  
Damage Potential ◽  
Research Activities ◽  
Federal Institute

Dynamics of dense, uniform spruce-dominated mountain forests Dense, uniform stands have increased in spruce-dominated mountain forests during the last century and often cause silvicultural problems. During recent years, different research activities at Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have addressed the development of such mountain forests with or without active management. For this, plots of the Swiss National Forest Inventory (NFI) between 1983/1985 and 2004/2006 have been analysed, dendroecological methods have been used to investigate competition and selfthinning processes and a reassessment of WSL long-term investigation plots has been conducted. NFI plots of stands which have already been dense during the first inventory period generally showed increasing basal area, stagnating stem numbers, strongly increasing amounts of deadwood and slightly increasing regeneration levels, both in managed and in unmanaged stands. Dendroecological field studies confirm that trees in the generally about 80 to 150 years old stands were strongly affected by competition-induced self-thinning and subsequent small-scale mortality processes few decades after stand initiation already. WSL long-term investigation plots generally confirm this dominance of relatively small-scale processes, but also show potential for silvicultural interventions, especially in early stages of self-thinning. According to the guidelines for silvicultural intervention in forests with protective functions (NAIS), an active management of later self-thinning stages with already short crowns and higher mortality should focus on stands where risks have to be considered as too high, based on hazard and damage potential and the size of the dense, uniform stands.

Incorporating intertree competition into an ecosystem model

1995 ◽  
Vol 25 (3) ◽  
pp. 413-424 ◽  
Author(s):  
R.L. Korol ◽  
S.W. Running ◽  
K.S. Milner
Keyword(s):  
Process Model ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Ecosystem Model ◽  
Growth And Yield ◽  
Maintenance Respiration ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Individual Trees

Current research suggests that projected climate change may influence the growth of individual trees. Therefore, growth and yield models that can respond to potential changes in climate must be developed, TREE-BGC, a variant of the ecosystem process model FOREST-BGC, calculates the cycling of carbon, water, and nitrogen in and through forested ecosystems. TREE-BGC allocates stand-level estimates of photosynthesis to "each tree using a competition algorithm that incorporates tree height, relative radiation-use efficiency, and absorbed photosynthetically active radiation, TREE-BGC simulated the growth of trees grown in a dense and an open stand of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near Kamloops, B.C. The competition algorithm dynamically allocated stand estimates of photosynthesis to individual trees, and the trees were grown using an allometric relationship between biomass increment and height and diameter increment. Asymptotic height growth and the changes in the height–diameter relationship with competition were also incorporated in the model algorithms. Sapwood and phloem volume were used to calculate maintenance respiration. Predicted reductions in diameter growth with stand density were similar to those observed in the study stands. Although the carbon balance of individual trees was not tested, simulated tree diameter increments and height increments were correlated with the actual measurements of tree diameter increment (r2 = 0.89) and tree height increment (r2 = 0.78) for the 5-year period (n = 352). Although the model did not work well with trees that had diameters <5 cm, the model would be appropriate for a user who required an accuracy of ± 0.03 m3•ha−1 for volume, ± 0.02 m2•ha−1 for basal area, or ± 0.4 m for tree height over a 5-year period.

Thinning ponderosa pine (Pinus ponderosa) stands reduces mortality while maintaining stand productivity

2013 ◽  
Vol 43 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Jianwei Zhang ◽  
Martin W. Ritchie ◽  
Douglas A. Maguire ◽  
William W. Oliver
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Bark Beetles ◽  
Basal Area ◽  
Stand Density ◽  
Growth Efficiency ◽  
Stand Age ◽  
Annual Increment ◽  
Stand Productivity ◽  
Residual Variation

We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI) of diameter, basal area (BA), volume, and aboveground dry mass were significantly related to stand density index (SDI) and stand age at start of the period; the quadratic trends varied among sites. Precipitation departure from the normal for each period explained a significant amount of residual variation in all PAI variables except diameter. BA production did not change significantly as SDI exceeded 270 trees·ha−1 at the OR sites and 320 trees·ha−1 at the CA site. Stand productivity was the highest at Elliot Ranch (CA) and the least at Blue Mountains (OR). A similar trend held in growth efficiency under lower stand densities (SDI < 600). Most of the mortality was caused by Dendroctonus bark beetles in stands that exceeded SDI of 500 trees·ha−1. Limiting SDI was about 900 trees·ha−1, although plots at Elliot Ranch reached much higher than that. The results demonstrate that silvicultural control of stand density can be a powerful tool for reducing bark beetle caused mortality without sacrificing stand productivity.

A new method for evaluating forest thinning: growth dominance in managed Pinus resinosa stands

2010 ◽  
Vol 40 (5) ◽  
pp. 843-849 ◽  
Author(s):  
John B. Bradford ◽  
Anthony W. D’Amato ◽  
Brian J. Palik ◽  
Shawn Fraver
Keyword(s):  
Tree Growth ◽  
Basal Area ◽  
Pinus Resinosa ◽  
Growth Patterns ◽  
Red Pine ◽  
New Method ◽  
Stand Age ◽  
Individual Tree ◽  
Individual Tree Growth

Growth dominance is a relatively new, simple, quantitative metric of within-stand individual tree growth patterns, and is defined as positive when larger trees in the stand display proportionally greater growth than smaller trees, and negative when smaller trees display proportionally greater growth than larger trees. We examined long-term silvicultural experiments in red pine ( Pinus resinosa Ait.) to characterize how stand age, thinning treatments (thinned from above, below, or both), and stocking levels (residual basal area) influence stand-level growth dominance through time. In stands thinned from below or from both above and below, growth dominance was not significantly different from zero at any age or stocking level. Growth dominance in stands thinned from above trended from negative at low stocking levels to positive at high stocking levels and was positive in young stands. Growth dominance in unthinned stands was positive and increased with age. These results suggest that growth dominance provides a useful tool for assessing the efficacy of thinning treatments designed to reduce competition between trees and promote high levels of productivity across a population, particularly among crop trees.

RPGrow$: A Red Pine Analysis Spreadsheet for the Lake States

1994 ◽  
Vol 11 (4) ◽  
pp. 141-145
Author(s):  
Carol A. Hyldahl ◽  
Gerald H. Grossman
Keyword(s):  
Financial Analysis ◽  
Basal Area ◽  
Site Index ◽  
Red Pine ◽  
Growth And Yield ◽  
Stand Age ◽  
Management Scenarios ◽  
Stand Management ◽  
Lake States ◽  
Final Harvest

Abstract RPGrow$ is a spreadsheet that interactively projects standlevel growth and yield with financial analysis of red pine plantations in the Lake States. Three types of commonly found conditions related to red pine management can be analyzed: (1) an entire rotation from initial planting to final harvest; (2) an existing stand from any point in time until final harvest; and (3) conversion of an existing stand to red pine (marginal analysis). Stand growth projections are for 70 yr. User input includes site index, stand age, initial basal area, trees per acre, thinning regime, costs associated with establishment and culture, tax rates, inflation rate, and discount rate. RPGrow$ calculates and values pulpwood and sawtimber volumes from user-defined stumpage prices. The financial analysis uses discounted cash flow methods to calculate results both with and without tax effects. Different stand management scenarios and economic factors can be compared easily through sensitivity analysis. North. J. Appl. For. 11(4):141-145.

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