Lecture 3B Flashcards
Lecture 3b. Forest Dynamics, Growth, and Yield (Part 2)
Why is Growth and Yield Modeling Important?
Helps predict future forest conditions, supports decision-making in forest management and conservation, and improves sustainable timber production and resource allocation.
What is Growth?
The increase in tree volume, biomass, or height over time.
The increase in tree volume, biomass, or height over time.
Growth
What is Yield?
The total volume of timber or biomass that can be harvested at a specific time.
The total volume of timber or biomass that can be harvested at a specific time.
Yield
What is Site Index?
A measure of site productivity based on the height of dominant trees at a reference age (e.g., 50 years for some species).
A measure of site productivity based on the height of dominant trees at a reference age (e.g., 50 years for some species).
Site Index
What is Annual Growth Rate?
Growth measured over a specific period, used to estimate long-term forest productivity.
Growth measured over a specific period, used to estimate long-term forest productivity.
Annual Growth Rate
What is Basal Area?
The cross-sectional area of all trees in a forest stand, used in growth calculations.
The cross-sectional area of all trees in a forest stand, used in growth calculations.
Basal Area
What is Increment?
The increase in tree size over time, categorized as current, mean, or periodic.
The increase in tree size over time, categorized as current, mean, or periodic.
Increment
Growth and Yield Models (5)
Annual Growth Rate
Deterministic Models
Stochastic Models
Empirical Models
Process-Based Models
What is the Annual Growth Rate formula?
Growth divided by the number of years in the period.
Growth divided by the number of years in the period.
Annual Growth Rate formula
What are Deterministic Models?
Models that predict fixed outcomes based on given input variables and assume no randomness, useful for controlled conditions.
Models that predict fixed outcomes based on given input variables and assume no randomness, useful for controlled conditions.
Deterministic Models
What are Stochastic Models?
Models that incorporate random variation to account for natural unpredictability and provide different possible outcomes with associated probabilities.
Models that incorporate random variation to account for natural unpredictability and provide different possible outcomes with associated probabilities.
Stochastic Models
What are Empirical Models?
Models based on observed data rather than theoretical assumptions, used for practical yield forecasting.
Models based on observed data rather than theoretical assumptions, used for practical yield forecasting.
Empirical Models
What are Process-Based Models?
Models that simulate physiological processes like photosynthesis and carbon allocation and require extensive field data and computational resources.
Models that simulate physiological processes like photosynthesis and carbon allocation and require extensive field data and computational resources.
Process-Based Models
What is the Estimation process in model development?
Determining statistical coefficients to describe growth and yield relationships.
Determining statistical coefficients to describe growth and yield relationships.
Estimation process in model development
What is Evaluation in model development?
Assessing model performance using accuracy tests and validation techniques.
Assessing model performance using accuracy tests and validation techniques.
Evaluation in model development
What is Verification in model development?
Ensures the model functions logically without errors.
Ensures the model functions logically without errors.
Verification in model development
What is Validation in model development?
Tests the model against real-world data to confirm accuracy.
Tests the model against real-world data to confirm accuracy.
Validation in model development
What is Sensitivity Analysis?
Examining how changes in input variables affect model predictions.
Examining how changes in input variables affect model predictions.
Sensitivity Analysis
What is Uncertainty Assessment?
Recognizing limitations in data collection and assumptions.
Recognizing limitations in data collection and assumptions.
Uncertainty Assessment
What is Simulation?
Uses computer models to estimate forest stand development over time and can test different scenarios for management planning.
Uses computer models to estimate forest stand development over time and can test different scenarios for management planning.
Simulation
What is Calibration
Adjusts the model to match specific local conditions (e.g., climate, soil type) and involves refining parameters to improve predictive accuracy.
Adjusts the model to match specific local conditions (e.g., climate, soil type) and involves refining parameters to improve predictive accuracy.
Calibration
What is Monitoring?
Continuous evaluation to refine predictions and correct errors, requiring long-term data collection for model updates.
Continuous evaluation to refine predictions and correct errors, requiring long-term data collection for model updates.
Monitoring
What is the relationship between model complexity and scale?
The complexity of forest processes and structures increases with temporal and spatial levels of integration: Tree → Stand → Landscape.
The complexity of forest processes and structures increases with temporal and spatial levels of integration: Tree → Stand → Landscape.
relationship between model complexity and scale
What are Black-Box Models?
Models that show statistical correlations between inputs & outputs without explaining underlying processes.
Models that show statistical correlations between inputs & outputs without explaining underlying processes.
Black-Box Models
What are White-Box Models?
Models that consider physiological and ecological processes, providing mechanistic insights.
Models that consider physiological and ecological processes, providing mechanistic insights.
White-Box Models
What are Whole Stand Models?
Models that estimate forest growth and yield at the stand level without differentiating between individual trees.
Models that estimate forest growth and yield at the stand level without differentiating between individual trees.
Whole Stand Models
Type of Whole Stand Models
Density-free models
Variable-density models
Diameter distribution models
What are Density-free models?
Models that assume maximum or average stand density and are the basis for traditional yield tables.
Models that assume maximum or average stand density and are the basis for traditional yield tables.
Density-free models
What are Variable-density models?
Models that use stand density as an explicit factor.
Models that use stand density as an explicit factor.
Variable-density models
What are Diameter distribution models?
Models that refine whole stand models by incorporating diameter class structure (tree size, height, volume).
Models that refine whole stand models by incorporating diameter class structure (tree size, height, volume).
Diameter distribution models
What are Diameter Class Models?
Models that simulate growth for each diameter class separately, summing volumes to obtain total stand volume.
Models that simulate growth for each diameter class separately, summing volumes to obtain total stand volume.
Diameter Class Models
What is the common approach for short-term predictions in Diameter Class Models
Stand table projection
Stand table projection
What is the common approach for short-term predictions in Diameter Class Models
Mortality, harvest, and ingrowth
must be computed separately in Diameter Class Models
What must be computed separately in Diameter Class Models
Mortality, harvest, and ingrowth
What are the assumptions of Diameter Class Models?
- All tree diameters in a diameter class equal the midpoint diameter for that class
- Trees of a diameter class all grow at the same average rate
What is the Movement ratio in Diameter Class Models?
Estimates the proportion of trees shifting to a higher DBH class.
What is the Movement ratio in Diameter Class Models?
Estimates the proportion of trees shifting to a higher DBH class.
Estimates the proportion of trees shifting to a higher DBH class.
Movement ratio in Diameter Class Models
What are the applications of Regression Models in Forest Management?
- Weight Scaling for Sawlogs (predicting sawlog volume based on truckload weight).
- Stem Taper Analysis (estimating volume distribution within a tree).
- Merchantable Volume Predictions (estimating usable wood volume for different top diameters).
- Biomass Prediction (tree weight estimations using DBH and height).
- Yield Estimation for Uneven-Aged Stands (predicting long-term forest productivity).
What is Site Index?
A measure of site quality based on dominant tree height at a reference/index age (e.g., 50-100 years), commonly used for even-aged stands.
A measure of site quality based on dominant tree height at a reference/index age (e.g., 50-100 years), commonly used for even-aged stands.
Site Index
What do Site index curves help predict?
Future stand height development.
Future stand height development.
Site index curves help predict
What are the types of site index curves?
Anamorphic curves
Polymorphic curves
Anamorphic curves
same shape, different intercepts
same shape, different intercepts
Anamorphic curves
different shapes and intercepts
Polymorphic curves
Polymorphic curves
different shapes and intercepts
