Sensitivity of Annual Diameter Increment and its Relationship with Climate: A Comparative Analysis of Five Broadleaf Deciduous Forest Tree Species
Open Access
- Author:
- Dannenberg, Samuel
- Graduate Program:
- Forest Resources
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 20, 2021
- Committee Members:
- Bradley Cardinale, Program Head/Chair
Laura P Leites, Thesis Advisor/Co-Advisor
Margot Wilkinson Kaye, Committee Member
Marc Eric Mc Dill, Committee Member - Keywords:
- Sensitivity of Annual Diameter Increment and its Relationship with Climate: A Comparative Analysis of Five Broadleaf Deciduous Forest Tree Species
- Abstract:
- Climate modifies tree growing environment, potentially impacting their annual diameter growth. Trees of different species may have different diameter growth response to climate because they have different physiological, morphological, genetic and adaptive characteristics. For example, trees from species with a ring-porous xylem structure start diameter growth earlier in the growing season than trees from species with a diffuse porous xylem structure. As a results, climate conditions at different times during the growing cycle may affect differently. In addition, trees with different competitive status in the forest may have differential diameter growth response to climate because they access different levels of resources potentially modified by climate. This thesis investigates tree diameter growth-climate relationships among five broadleaf deciduous tree species at four mixed hardwood forested sites in Southeastern Pennsylvania. These species are: black walnut (Juglans nigra L.), red maple (Acer rubrum), tree-of-heaven (Ailanthus altissima Mill. Swingle), tulip poplar (Liriodendron tulipifera L.) , and white oak (Quercus alba L.). I combine dendrochronological and annual/seasonal climate data with statistical analyses and modeling to understand: 1) potential differences in diameter growth sensitivity among the focus species, 2) potential differences in diameter growth sensitivity among trees of different competitive status in red maple and tulip poplar, 3) relationship between diameter growth sensitivity and climate variability, and 4) relationships between growth and climate. Diffuse-porous red maple and tulip poplar displayed higher diameter growth sensitivity, while ring-porous white oak and tree-of-heaven displayed lower diameter growth sensitivity, and black walnut displayed intermediate sensitivity. Further study should incorporate more tree species to investigate this relationship. We did not detect differences in diameter growth sensitivity among trees of different competitive statuses in red maple and tulip poplar. The variability of many climate variables was associated with diameter growth sensitivity in tulip poplar, and few associations were detected in black walnut. We used linear mixed effects models and random forests to model relationships between diameter growth, estimated as ring width index, and climate predictors for the current and previous year. Models explained the most variance in ring width index in tulip poplar, white oak, and tree-of-heaven. Models did not explain variation in red maple and explained little variation (2.3%) in black walnut. Previous year climate across seasons and current year climate in the growing season (May-September) appear important to current year growth.