Structural development of redwood branches and its effect on wood growth

Graduation Date

2013

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Forest, Watershed, & Wildland Sciences, 2013

Committee Chair Name

Stephen Sillett

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Wood production, Branch, Age-related decline, Reproduction, Tree aging, Heartwood deposition, Humboldt State University -- Theses -- Forestry

Abstract

To determine how branch tissue development affects wood volume growth we studied 31 branches from 8 Sequoia sempervirens and 7 Sequoiadendron giganteum trees. Branch heights ranged from 15.6 - 104.5 m, diameters from 3.4 - 13.6 cm, ages from 11 – 258 years, and wood production from 3.4 - 80.3 cm3 per year. The cambium-to-leaf-area ratio did not change with size or age but increased with height and light availability. Heartwood area was calculated as the surface of heartwood deposition. The heartwood-area-to- leaf-area ratio increased with both size and age. The heartwood-area-to-cambium ratio increased with size, age, and decreased with light availability. A set of models were compared with corrected Akaike's Information Criterion (AICc). The best model with 99.4 % of the AICc model weight used branch size, light, species, heartwood area, a heartwood area - species interaction, and green cone mass to predict 87.5 % of the variability in wood volume growth. After accounting for positive effects of size and light, wood volume growth declined with both heartwood area and age, but the age effect was trivial compared to heartwood area. These results suggest that age-related declines in wood volume growth may be caused by expansion of the heartwood sink within branches. Additionally, cone production was negatively correlated with wood volume growth in Sequoiadendron giganteum branches even though the cones are long-lived and photosynthetic. We used these results to present a structural model for branch development. Heartwood accumulates more slowly in well-illuminated branches. These branches in turn have less heartwood sink potential to detract from future wood production. Injury and light availability interact to change the developmental trajectory of branches.

https://scholarworks.calstate.edu/concern/theses/n009w464r

Link to Full Text

Share

 
COinS