Stand, species, and tree dynamics of an uneven-aged, mixed conifer forest type

1995 ◽  
Vol 25 (5) ◽  
pp. 803-812 ◽  
Author(s):  
John P. McTague ◽  
William F. Stansfield
Keyword(s):  
Tree Mortality ◽  
Forest Type ◽  
Species Abundance ◽  
Basal Area ◽  
Logistic Function ◽  
Conifer Forest ◽  
Individual Tree ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Tree Survival

Stand-level equations are presented that project future merchantable tree survival, pole-tree basal area, and sawtimber basal area. Total basal area (excluding ingrowth) is the sum of the pole-tree and sawtimber components. Ratio equations are used for eight species (seven softwoods and one hardwood) to compute the change in species abundance and species basal area over time. Individual-tree mortality is predicted with a logistic function, while individual-tree diameter growth is predicted as a function of stand and individual-tree attributes. The individual-tree and species-level equations are adjusted so that tree frequency and basal area are consistent with the stand-level projection equations. Total ingrowth is computed with a stand-level projection equation and is distributed with a parameter recovery method using the uniform distribution. The presence or absence of ingrowth for a given species is determined with a discriminant function, while the proportion of total ingrowth allocated to a species is predicted with a logistic function.

scholarly journals Stand Dynamics of the Spruce-Fir Forest in East-Central Arizona

1997 ◽  
Vol 12 (2) ◽  
pp. 55-61
Author(s):  
Pedro Moran-Palma ◽  
John P. McTague
Keyword(s):  
Tree Mortality ◽  
Forest Type ◽  
Logistic Function ◽  
Data Set ◽  
Individual Tree ◽  
East Central ◽  
Continuous Forest ◽  
Class Level ◽  
The Individual ◽  
Central Arizona

Abstract New functions are presented for spruce-fir survivor growth, ingrowth, and mortality using a data set of Continuous Forest Inventory plots exclusively from the spruce-fir forest type in east-central Arizona. The individual tree diameter squared growth model is validated at the tree and stand level with an independent data set. Individual tree mortality is modeled for any projection interval with a logistic function. Ingrowth dynamics is modeled at three levels of resolution; the stand level, species level, and the diameter class level. Ingrowth trees are distributed to diameter classes using the Uniform distribution. West. J. Appl. For. 12(2):55-61.

Implementation constraints limit benefits of restoration treatments in mixed-conifer forests

2019 ◽  
Vol 28 (7) ◽  
pp. 495 ◽  
Author(s):  
Jamie M. Lydersen ◽  
Brandon M. Collins ◽  
Carolyn T. Hunsaker
Keyword(s):  
Sierra Nevada ◽  
Forest Structure ◽  
Forest Restoration ◽  
Tree Mortality ◽  
Canopy Cover ◽  
Basal Area ◽  
Severe Drought ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Trade Offs

Forest restoration treatments seek to increase resilience to wildfire and a changing climate while avoiding negative impacts to the ecosystem. The extent and intensity of treatments are often constrained by operational considerations and concerns over uncertainty in the trade-offs of addressing different management goals. The recent (2012–15) extreme drought in California, USA, resulted in widespread tree mortality, particularly in the southern Sierra Nevada, and provided an opportunity to assess the effects of restoration treatments on forest resilience to drought. We assessed changes in mixed-conifer forest structure following thinning and understorey burning at the Kings River Experimental Watersheds in the southern Sierra Nevada, and how treatments, topography and forest structure related to tree mortality in the recent drought. Treatments had negligible effect on basal area, tree density and canopy cover. Following the recent drought, average basal area mortality within the watersheds ranged from 5 to 26% across riparian areas and 12 to 44% across upland areas, with a range of 0 to 95% across all plots. Tree mortality was not significantly influenced by restoration treatments or topography. Our results suggest that the constraints common to many restoration treatments may limit their ability to mitigate the impacts of severe drought.

Etiology of canopy gaps in spruce–fir forests at Crawford Notch, New Hampshire

1988 ◽  
Vol 18 (11) ◽  
pp. 1463-1469 ◽  
Author(s):  
J. J. Worrall ◽  
T. C. Harrington
Keyword(s):  
Forest Canopy ◽  
Forest Type ◽  
Basal Area ◽  
Natural Disturbance ◽  
Ground Level ◽  
Canopy Gaps ◽  
Relative Importance ◽  
Conifer Forest ◽  
Canopy Trees ◽  
Spruce Beetle

Natural disturbance agents causing formation of canopy gaps were identified and quantified at five elevations (640, 765, 885, 1005, and 1130 m) in an old-growth spruce–fir forest. Actual and expanded gaps were measured to the inner edge of the crown or to the bole, respectively, of the live canopy trees at the gap margin. The percentage of forest canopy in gaps was lowest (6% for actual and 40% for expanded gap areas) at 1005 m elevation, near the upper limit of the spruce–fir phase, and highest (33% actual and 77% expanded) where the spruce–fir phase meets the mixed hardwood–conifer forest type at 765 m elevation. Mean gap size was smallest at the higher elevations. Expanded gap area was apportioned to tree species and disturbance agents according to basal area of affected trees in each gap. Twenty-two identified agents were involved in gap-phase mortality, and their relative importance varied strongly with elevation. Biotic diseases accounted for 66% of gap area at the lowest elevation (640 m) and only 7 and 15%, respectively, at the highest elevations (1005 and 1130 m). Root and butt rots were the most important group of biotic diseases at all elevations; their primary effect was to predispose trees to breakage of the stem near ground level. In contrast to biotic disease agents, chronic wind stress increased greatly in relative importance with elevation, accounting for 72% of gap area at 1130 m. The spruce beetle was an important disturbance agent at 640 and 765 m, where large, overmature red spruce trees had dominated the stand. Gap etiology appeared to be rarely restricted in time to a single event, and was often complex, with multiple agents occurring in the same gap and on the same tree.

Improving estimates of tree mortality probability using potential growth rate

2015 ◽  
Vol 45 (7) ◽  
pp. 920-928 ◽  
Author(s):  
Adrian J. Das ◽  
Nathan L. Stephenson
Keyword(s):  
Growth Rate ◽  
Sierra Nevada ◽  
Tree Mortality ◽  
Basal Area ◽  
Growth Index ◽  
Diameter Growth ◽  
Potential Growth ◽  
Mortality Probability ◽  
Growth Metrics ◽  
Tree Survival

Tree growth rate is frequently used to estimate mortality probability. Yet, growth metrics can vary in form, and the justification for using one over another is rarely clear. We tested whether a growth index (GI) that scales the realized diameter growth rate against the potential diameter growth rate (PDGR) would give better estimates of mortality probability than other measures. We also tested whether PDGR, being a function of tree size, might better correlate with the baseline mortality probability than direct measurements of size such as diameter or basal area. Using a long-term dataset from the Sierra Nevada, California, U.S.A., as well as existing species-specific estimates of PDGR, we developed growth–mortality models for four common species. For three of the four species, models that included GI, PDGR, or a combination of GI and PDGR were substantially better than models without them. For the fourth species, the models including GI and PDGR performed roughly as well as a model that included only the diameter growth rate. Our results suggest that using PDGR can improve our ability to estimate tree survival probability. However, in the absence of PDGR estimates, the diameter growth rate was the best empirical predictor of mortality, in contrast to assumptions often made in the literature.

An individual-tree basal area growth model for loblolly pine stands

1996 ◽  
Vol 26 (2) ◽  
pp. 327-331 ◽  
Author(s):  
Paul A. Murphy ◽  
Michael G. Shelton
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Growth Function ◽  
Logistic Function ◽  
Growth Patterns ◽  
Potential Growth ◽  
Individual Tree ◽  
Basal Area Growth ◽  
Area Growth ◽  
Using Data

Tree basal area growth has been modeled as a combination of a potential growth function and a modifier function, in which the potential function is fitted separately from open-grown tree data or a subset of the data and the modifier function includes stand and site variables. We propose a modification of this by simultaneously fitting both a growth component and a modifier component. The growth component can be any function that approximates tree growth patterns, and the logistic function is chosen as the modifier component. This approach can be adapted to a variety of stand conditions, and its application is demonstrated using data from an uneven-aged loblolly pine (Pinustaeda L.) study located in Arkansas and Louisiana.

scholarly journals Precommercial Thinning in a Ponderosa Pine Stand Affected by Armillaria Root Disease in Central Oregon: 30 Years of Growth and Mortality

1999 ◽  
Vol 14 (3) ◽  
pp. 144-148 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Lisa M. Ganio
Keyword(s):  
Ponderosa Pine ◽  
Tree Mortality ◽  
Basal Area ◽  
Stand Density ◽  
Root Disease ◽  
Diameter Growth ◽  
Individual Tree ◽  
Precommercial Thinning ◽  
Tree Diameter ◽  
Armillaria Root Disease

Abstract A 30-yr-old stand of ponderosa pine was precommercially thinned in 1966 to determine the effects of thinning on tree growth and mortality caused by Armillaria root disease in central Oregon. After 30 yr, crop tree mortality was significantly (P = 0.02) less in thinned plots than in unthinned plots. Tree diameter growth was not significantly (P = 0.17) increased by thinning. Crop-tree basal area/ac growth was significantly (P = 0.03) greater in thinned plots. Apparently, from a root disease perspective, precommercial thinning of pure ponderosa stands significantly decreases the incidence of crop-tree mortality after 30 yr and significantly increases basal area/ac growth but not individual tree diameter growth. Recommendations for thinning based on stand density index (SDI) are given. West. J. Appl. For. 14(3):144-148.

Projection of a diameter distribution through time

2007 ◽  
Vol 37 (1) ◽  
pp. 188-194 ◽  
Author(s):  
Jianhua Qin ◽  
Quang V Cao ◽  
David C Blouin
Keyword(s):  
Projection Method ◽  
Loblolly Pine ◽  
Growth Period ◽  
Distribution Model ◽  
Diameter Distribution ◽  
Tree Model ◽  
Individual Tree ◽  
Recovery Method ◽  
Tree Survival ◽  
Individual Tree Model

Three approaches to characterizing the diameter distribution of a future stand are presented. The first approach is the "parameter-recovery" method, which links a whole-stand model to a diameter-distribution model. The next two approaches provide linkages between an individual-tree model and a diameter-distribution model. Tree-survival and diameter-growth equations were applied to the tree list (the "tree-projection" method) or to the diameter distribution (the "distribution-projection" method) at the beginning of the growth period. A numerical example of Weibull distributions that characterized diameter data from the Southwide Seed Source Study of loblolly pine (Pinus taeda L.) is presented. All three methods produced similar results in terms of Reynolds et al.'s (1988) error indices, whereas the distribution-projection method outperformed the other two methods in predicting total and merchantable volumes per hectare. This study demonstrated that the diameter-distribution model could be linked to either a whole-stand model or an individual-tree model with comparable success.

An individual-based growth and competition model for coastal redwood forest restoration

2014 ◽  
Vol 44 (9) ◽  
pp. 1051-1057 ◽  
Author(s):  
Phillip van Mantgem ◽  
Adrian Das
Keyword(s):  
Tree Growth ◽  
Forest Restoration ◽  
Forest Type ◽  
Basal Area ◽  
Species Identity ◽  
Individual Tree ◽  
Individual Tree Growth ◽  
Redwood Forests ◽  
Underlying Mechanisms ◽  
Redwood Forest

Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

Evaluation of distance-independent competition indices in predicting tree survival and diameter growth

2019 ◽  
Vol 49 (5) ◽  
pp. 440-446 ◽  
Author(s):  
Shuaichao Sun ◽  
Quang V. Cao ◽  
Tianjian Cao
Keyword(s):  
Loblolly Pine ◽  
Relative Position ◽  
Basal Area ◽  
Diameter Ratio ◽  
Cumulative Distribution ◽  
Permanent Plots ◽  
Diameter Growth ◽  
Individual Tree ◽  
Tree Survival ◽  
Competition Indices

Competition indices play a significant role in modeling individual-tree growth and survival. In this study, six distance-independent competition indices were evaluated using 200 permanent plots of loblolly pine (Pinus taeda L.). The competition indices were classified into three families: (1) size ratios, which include diameter ratio and basal area ratio; (2) relative position indices, which include basal area of larger trees (BAL) and tree relative position based on the cumulative distribution function (CDF); and (3) partitioned stand density index and relative density. Results indicated that different families of competition indices were suitable for different tree survival or diameter growth prediction tasks. The diameter ratio was superior for predicting tree survival, whereas the relative position indices (BAL and CDF) performed best for predicting tree diameter growth, with CDF receiving the highest rank.

scholarly journals Generalized Nonlinear Mixed-Effects Individual Tree Crown Ratio Models for Norway Spruce and European Beech

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 555 ◽  
Author(s):  
Ram Sharma ◽  
Zdeněk Vacek ◽  
Stanislav Vacek
Keyword(s):  
Norway Spruce ◽  
Model Fitting ◽  
Basal Area ◽  
European Beech ◽  
Logistic Function ◽  
Mixed Effects ◽  
Mixed Effects Model ◽  
Individual Tree ◽  
Mixed Effects Modeling ◽  
Species Mixture

Tree crowns are commonly measured to understand tree growth and stand dynamics. Crown ratio (CR—crown depth-to-total height ratio) is significantly affected by a number of tree- and stand-level characteristics and other factors as well. Generalized mixed-effects CR models were developed using a large dataset (measurements from 14,669 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica (L.)) acquired from permanent research plots in various parts of the Czech Republic. Among several tree- and stand-level variables evaluated, diameter at breast height, height to crown base, dominant height, basal area of trees larger in diameter than a focal tree, relative spacing index, and variables describing the effects of species mixture and canopy height differentiation significantly contributed to CR variation. We included sample-plot-level variations caused by randomness in the data and other stochastic factors into the CR models using the mixed-effects modeling approach. The logistic function, which predicts the values between 0 and 1, was chosen to develop the generalized CR mixed-effects model. A large proportion of the CR variation (R2adj ≈ 0.63 (Norway spruce); 0.72 (European beech)) was described by generalized mixed-effects model without significant residual trends. Testing the CR model against a part of the model fitting dataset confirmed its high prediction precision. Our CR model can be useful for growth simulation using inventory databases that lack crown measures. Other potential implications of our CR models in forest management are mentioned in the article.

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