Lecture 13 FORE 3218 Forest Mensuration II Lecture 13 Growth and Yield Models Avery and Burkhart, Chapter 16

Lecture 13 FORE 3218 A few thoughts  Forest management decisions-making relies on accurate information about both current and future forest resource conditions  Stand-table projections for future growth based on the past may be most accurate for a limited period of time, but –Not reliable for long periods –Not necessarily useful for evaluate treatment alternatives because …  Therefore, many models for forecasting stand dynamics are developed, ranging from tables, equations, to computer simulation models

Lecture 13 FORE 3218 Definition of yield  The total amount available at a given point of time –gross volume –merchantable volume –biomass

Lecture 13 FORE 3218 Definition of yield (cont.) – Merchantability B Potential usable growth under present technology and policy C Growth actually removed and utilized A Total biological growth Growth 30 cm OMNR (1995) Scaling Manual Top D Merchantable 10 cm: Pj, Sb, Sw, Bf, Ce 16 cm: Pw, Pr, He, Po, Bw 20 cm: other hardwoods

Lecture 13 FORE 3218 Definition of yield (cont.) Gross Plonski 1974 Merch Merchantability

Lecture 13 FORE 3218 Definition of growth  The increase (increment) over a given period of time –Mean annual increment (MAI) –Periodic annual increment (PAI)

Lecture 13 FORE 3218 Definition of growth (cont.) MAI

Lecture 13 FORE 3218 Definition of growth (cont.) PAI

Lecture 13 FORE 3218 Relationships between yield and growth

Lecture 13 FORE 3218 Types of Models Whole stand models Diameter class models Individual tree models Simple Sophisticated Development Even-aged Uneven-aged Application Empirical Process Nature

Lecture 13 FORE 3218 Whole stand models  Density-free models –Normal yield tables –Empirical yield tables for average stands  Variable density models –Predict yield –Predict growth (g 12 ) and yield (V 1 ) Equations Model type

Lecture 13 FORE 3218 Diameter class models  Empirical stand table projections Equations Model type

Lecture 13 FORE 3218 Individual tree models Equations Model type  Distance-dependent  Distance-independent

Lecture 13 FORE 3218 Which type of models is best suited for the following situations? Why?  Depends on purposes of modeling…, but if … –Even-aged, single species stands? –Uneven-aged single species stands? –Even- and uneven-aged, mixed-species stands?

Lecture 13 FORE 3218 FVS Ontario version 1.0 Visualization - The power of arts