JABOWA

• Janick, Botkin, and Wallis

• Individual tree

• Not location dependent

• ‘gap model’

Driving equation is diameter

• Mitscherlich equation

• Diameter growth = G*LIGHT*AET*TEMP …

• G (max growth) based on record trees

• LIGHT based in physiologic experiments

• AET, TEMP etc. based on natural range

3 Modules (can be turned on/off)

• Birth

• Growth

• Death

Birth

• Stochastically adds saplings– Based on total leaf area of species in the plot

Growth

• Must have estimate of growth potential

– Diameter growth = G*LIGHT*AET*TEMP …

• Record trees or backcasting estimate

– For short term growth

• Asymptotic growth based on maximum age

Foliage

Light

• What reaches top of tree

• Uses Beers-Lambert light extinction law

– Neutral density filter

QuadraticP

ote

nti

al g

row

th

100%

Temperature (degree days)

QuadraticP

ote

nti

al g

row

th

100%

AET

Plot size

• Gap model

– Goes to 1 large tree

– 10m X 10m

• Add subtract plots

Kill

• Expectation = 4/AgeMax [for ‘normal growth rates]

• Slow growers 99% (for 10 years)

• Stochastic

• To follow specific trees they can be given an #ID

Some details

• Only grows dbh

– Everything else is regressed

• FORET (problems with over parameterization)

– Competition

• Plot size is crucial [10m X 10m is basic]

M. Irfan Ashraf Charles P.-A. Bourque, David A. MacLean, Thom Erdle and Fan-Rui Meng (2012)

M. Irfan Ashraf Charles P.-A. Bourque, David A. MacLean, Thom Erdle and Fan-Rui Meng (2012)

TASS

• Tree And Stand Simulator

• Individual tree model

• Location dependent

– Based on crown development

• Grows crowns

• Wood is a regressed set of variables

The petri dish

Greatest development was

based on Douglas fir

• First structured on white spruce

• Eventually modified for other species

• Based on the concepts of ‘lollipops’

– First proposed by David Smith in the 60’s

Assumption of a repeatable

crown shape

• First proposed by Halle in the early 70’s

– Based on theory of reiterative branching patterns

• Douglas fir is parabolic

Paraboloid

10

7

5

4

Increasing at a decreasing rate

10

10

7

10

7

5

10

Branches disappear

Foliage contribution

Bole increment

• BI = aFVk

Pressler’s Law

The lollipop concept

Lollipop + Pressler = bole

How to get differentiation

Death

• Any tree where leader is overtopped

Back to the petri dish

• New grid system

• Light model tRAYci (Brunner 2008)

• New grid system = new models

From: TASS III: Simulating the management, growth and yield of complex stands. Final Report. Y083088

Proportion of above canopy light (PACL)

From: TASS III: Simulating the management, growth and yield of complex stands. Final Report. Y083088 & Brunner, A. 1998. A light model for spatially explicit forest stand models. For. Ecol. Manage. 107:19–46.

PACL

PACL

From: TASS III: Simulating the management, growth and yield of complex stands. Final Report. Y083088