TY  - JOUR
A1  - Dorji, Yonten
A1  - Schuldt, Bernhard
A1  - Neudam, Liane
A1  - Dorji, Rinzin
A1  - Middleby, Kali
A1  - Isasa, Emilie
A1  - Körber, Klaus
A1  - Ammer, Christian
A1  - Annighöfer, Peter
A1  - Seidel, Dominik
T1  - Three-dimensional quantification of tree architecture from mobile laser scanning and geometry analysis
JF  - Trees
N2  - Key message
Mobile laser scanning and geometrical analysis revealed relationships between tree geometry and seed dispersal mechanism, latitude of origin, as well as growth.

Abstract
The structure and dynamics of a forest are defined by the architecture and growth patterns of its individual trees. In turn, tree architecture and growth result from the interplay between the genetic building plans and environmental factors. We set out to investigate whether (1) latitudinal adaptations of the crown shape occur due to characteristic solar elevation angles at a species’ origin, (2) architectural differences in trees are related to seed dispersal strategies, and (3) tree architecture relates to tree growth performance. We used mobile laser scanning (MLS) to scan 473 trees and generated three-dimensional data of each tree. Tree architectural complexity was then characterized by fractal analysis using the box-dimension approach along with a topological measure of the top heaviness of a tree. The tree species studied originated from various latitudinal ranges, but were grown in the same environmental settings in the arboretum. We found that trees originating from higher latitudes had significantly less top-heavy geometries than those from lower latitudes. Therefore, to a certain degree, the crown shape of tree species seems to be determined by their original habitat. We also found that tree species with wind-dispersed seeds had a higher structural complexity than those with animal-dispersed seeds (p < 0.001). Furthermore, tree architectural complexity was positively related to the growth performance of the trees (p < 0.001). We conclude that the use of 3D data from MLS in combination with geometrical analysis, including fractal analysis, is a promising tool to investigate tree architecture.
KW  - tree architecture
KW  - LiDAR
KW  - fractal analysis
KW  - seed dispersal strategy
KW  - latitude
KW  - tree growth
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-307501
SN  - 0931-1890
SN  - 1432-2285
VL  - 35
IS  - 4
ER  - 
TY  - JOUR
A1  - Röll, Alexander
A1  - Ramesha, Mundre N.
A1  - Link, Roman M.
A1  - Hertel, Dietrich
A1  - Schuldt, Bernhard
A1  - Patil, Shekhargouda L.
A1  - Hölscher, Dirk
T1  - Water availability controls the biomass increment of Melia dubia in South India
JF  - Forests
N2  - Farmland tree cultivation is considered an important option for enhancing wood production. In South India, the native leaf-deciduous tree species Melia dubia is popular for short-rotation plantations. Across a rainfall gradient from 420 to 2170 mm year\(^{–1}\), we studied 186 farmland woodlots between one and nine years in age. The objectives were to identify the main factors controlling aboveground biomass (AGB) and growth rates. A power-law growth model predicts an average stand-level AGB of 93.8 Mg ha\(^{–1}\) for nine-year-old woodlots. The resulting average annual AGB increment over the length of the rotation cycle is 10.4 Mg ha\(^{–1}\) year\(^{–1}\), which falls within the range reported for other tropical tree plantations. When expressing the parameters of the growth model as functions of management, climate and soil variables, it explains 65% of the variance in AGB. The results indicate that water availability is the main driver of the growth of M. dubia. Compared to the effects of water availability, the effects of soil nutrients are 26% to 60% smaller. We conclude that because of its high biomass accumulation rates in farm forestry, M. dubia is a promising candidate for short-rotation plantations in South India and beyond.
KW  - aboveground biomass
KW  - climatological water deficit
KW  - farm forestry
KW  - farmland woodlots
KW  - rainfall gradient
KW  - soil
KW  - wood production
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250150
SN  - 1999-4907
VL  - 12
IS  - 12
ER  -