Risto Sievänen1

Eero Nikinmaa2

Christian Messier3

Jari Perttunen1

1. The Finnish Forest Research Institute 2. Dept. of Forest Ecology, University of Helsinki3. GREF, Université du Québec à Montréal

Modeling the effects of metabolism and 3D crown structure on tree growth

CONTENTS

Functional-structural tree models

The Model LIGNUM

Some Applications

Conclusions

Process-based models

Vegetative and reproductive growth Photosynthesis, respiration and carbon allocation Mineral metabolism, especially nitrogen

metabolism Growth regulations Intra-tree transfer of metabolites

Morphological models

• L-systems

• Other mathematical presentations of branching systems

Here comes a pictrue from Algorithmic beauty of plants

Process-based model

Morphological model

=

Functional-structural model (FSM)

Features of a FSM

• A basic unit is used for presentation of both architecture and functioning (metabolism)

• These units are combined to form different organisational levels

• Local control

LIGNUM: General features

Simple structural units account for both structure and functioning of trees.

Annual net production is used to new growth.

Pipe model and functional balance for partitioning of growth.

Time step one growth period (one year).

LIGNUM: The structure

LIGNUM: Tree Segment for deciduous trees

LIGNUM: Releasing suppressed buds

LIGNUM: Carbon balance

LIGNUM: Length of new segments

LIGNUM: New buds

LIGNUM: The Radiation Submodel (self shading)

Shading

Shaded

Scots pine

• Scots pine and Jack pine the first two tree species implemented.

• Proved the modeling approach feasible.

• Modeled (published) trees 10 years old.

Sugar maple

Study the survival and growth of sugar maple saplings in forest gaps.

Cutting guidelines for natural regeneration of sugar maple: Size of the canopy

openings Frequency of cuttings

Three 5 year old saplings in St-Hilaire

Closed Gap Released Zenith Open Gap

L = 1.37m

L = 2.43mL = 2.84m

Gliricidia sepium

Nitrogen fixing tropical tree species used in agroforestry.

Study the optimal management (frequency of cuttings).

Mountain birch

Structural analysis of mountain birch

Based on detailed measurements done in Finnish Lapland

Analysis of Sapflow

Concluding Remarks

To be added

www.metla.fi/projects/lignum