Understanding crown shyness from a 3-D perspective

Area of Science:

• Ecology
• Forestry
• Botany

Background:

• Crown shyness is a canopy phenomenon where tree crowns avoid contact, forming unique patterns.
• Previous research linked tree slenderness to crown shyness but often used 2-D methods.
• This study introduces a novel 3-D approach to quantify crown shyness.

Purpose of the Study:

• To quantify 3-D surface complementarity between adjacent tree crowns exhibiting crown shyness.
• To assess the relationship between this 3-D crown surface complementarity and tree slenderness.
• To develop new metrics for crown shyness analysis using LiDAR data.

Main Methods:

• Utilized LiDAR to create 3-D point clouds of 14 individual trees.
• Applied a surface complementarity (Sc) metric, adapted from molecular biology, to adjacent tree pairs.
• Generated 3-D tree crown surfaces using α shapes from point cloud data.

Main Results:

• Tree pairs with non-overlapping crowns showed significantly higher Sc values than overlapping pairs.
• A positive correlation was found between the average slenderness of tree pairs and their Sc score (R² = 0.484, P < 0.01).
• Results align with previous studies linking tree slenderness to crown shyness.

Conclusions:

• Successfully quantified crown surface complementarity in crown shyness using a 3-D metric.
• Confirmed a positive relationship between crown surface complementarity and tree slenderness.
• The 3-D metric elucidates how trees adjust crown shape based on neighbors and slenderness.